Mate Lib. AGRI
U. S. DEPARTMENT OF AGRICULTURE.
BUREAU OF PLANT INDUSTRYBULLETIN NO. 53.
B. T. (!ALL()\\ AY, Chief (
THE DATE PALM
AND
ITS UTILIZATION IN THE SOUTHWESTERN STATES,
WALTER T. SWINGLE,
PHYSIOLOGIST IN CHARGE OF LABORATORY OF PLANT LIFK HISTORY.
VEGETABLE PATHOLOGICAL AND PHYSIOLOGICAL
INVESTIGATIONS.
TSS1KI> A I'KIL L'S, l!>04.
WASHINGTON:
G OV K H N M K N T I 1 K I N T I N ( : < ' F 1 I I .
BULLETINS OF THE BUREAU OF PLANT INDUSTRY.
The Bureau of Plant Industry, which was organized. July 1, 1901, includes Vege-
table Pathological and Physiological Investigations, Botanical Investigations and
Experiments, Grass and Forage Plant Investigations, Pomological Investigations, and
Experimental Gardens and Grounds, all of which were formerly separate Divisions,
and also Seed and Plant Introduction and Distribution, the Arlington Experimental
Farm, Tea Culture Investigations, and Domestic Sugar Investigations.
Beginning with the date of organization of the Bureau, the several series of Bulle-
tins of the various Divisions were discontinued, and all are now published as one
series of the Bureau. A list of the Bulletins issued in the present series follows.
Attention is directed to the fact that "the serial, scientific, and technical publica-
tions of the United States Department of Agriculture are not for general distribution.
All copies not required for official use are by law turned over to the Superintendent
of Documents, who is empowered to sell them at cost." All applications for such
publications should, therefore, be made to the Superintendent of Documents, Union
Building, Washington, D. C.
No. 1. The Relation of Lime and Magnesia to Plant Growth. I. Liming of Soils
from a Physiological Standpoint. II. Experimental Study of the Relation
of Lime and Magnesia to Plant Growth. 1901. Price, 10 cents.
2. Spermatogenesis and Fecundation of Zamia. 1901. Price, 20 cents.
3. Macaroni Wheats. 1901. Price, 20 cents.
4. Range Improvement in Arizona. (Cooperative Experiments with the
Arizona Experiment Station. ) 1902. Price, 10 cents.
5. Seeds and Plants Imported Through the Section of Seed and Plant Intro-
duction. Inventory No. 9, Nos. 4351-5500. 1902. Price, 10 cents.
6. A List of American Varieties of Peppers. 1902. Price, 10 cents.
7. The Algerian Durum Wheats: A Classified List, with Descriptions. 1902.
Price, 15 cents.
8. A Collection of Economic and Other Fungi Prepared for Distribution. 1902.
Price, 10 cents.
9. The North American Species of Spartina. 1902. Price, 10 cents.
10. Records of Seed Distribution and Cooperative Experiments with Grasses and
Forage Plants. 1902. Price, 10 cents.
11. Johnson Grass: Report of Investigations Made During the Season of 1901.
1902. Price, 10 cents.
12. Stock Ranges of Northwestern California: Notes on the Grasses and Forage
Plants and Range Conditions. 1902. Price, 15 cents.
13. Experiments in Range Improvement in Central Texas. 1902. Price, 10
cents.
14. The Decay of Timber and Methods of Preventing It. 1902. Price, 55 cents.
15. Forage Conditions on the Northern Border of the Great Basin. 1902. Price,
15 cents.
16. A Preliminary Study of the Germination of the Spores of Agaricus Campes-
tris and Other Basidiomycetous Fungi. 1902. Price, 10 cents.
17. Some Diseases of the Cowpea: I. The Wilt Disease of the Cowpea and Its
Control. II. A Cowpea Resistant to Root Knot (Heterodera Radicicola).
1902. Price, 10 cents.
18. Observations on the Mosaic Disease of Tobacco. 1902. Price, 15 cents.
19. Kentucky Bluegrass Seed: Harvesting, Curing, and Cleaning. 1902. Price,
10 cents.
20. Manufacture of Semolina and Macaroni. 1902. Price, 15 cents.
[Continued 011 page 3 of cover.]
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE I.
OLD DATE PALMS AT HERMOSILLO, NORTHERN MEXICO.
U. S. DEPARTMENT OF AGRICULTURE.
BUREAU OF PLANT INDUSTRYBULLETIN NO. 53.
B. T. GALLOWAY, Chief of Bureau.
THE DATE PALM
ITS UTILIZATION IN THE SOUTHWESTERN STATES.
WALTER T. SWINGLE,
'(
PHYSIOLOGIST IN CHARGE OF LABORATORY OF PLANT LIFE HISTORY.
VEGETABLE PATHOLOGICAL AND PHYSIOLOGICAL
INVESTIGATIONS.
ISSUED APRIL 28, 1904.
WASHINGTON:
GOVERNMENT PRINTING OFFICE,
1904.
BUREAU OF PLANT INDUSTRY.
B. T. GALLOWAY,
J. E. ROCKWELL, Editor.
VEGETABLE PATHOLOGICAL AND PHYSIOLOGICAL INVESTIGATIONS.
SCIENTIFIC STAFF.
ALBERT F. WOODS, Pathologist and Physiologist.
ERWIN F. SMITH, Pathologist in Charge of Laboratory of Plant Pathology.
GEORGE T. MOORE, Physiologist in Charge of Laboratory of Plant Physiology.
HERBERT J. WEBBER, Physiologist in Charge of Laboratory of Plant Breeding.
WALTER T. SWINGLE, Physiologist in Charge of Laboratory of Plant Life History.
NEWTON B. PIERCE, Pathologist in Charge of Pacific Coast Laboratory.
M. B. WAITE, Pathologist in Charge of Investigations of Diseases of Orchard Fruits.
MARK A. CARLETON, Cerealist in Charge of Cereal Investigations.
HERMANN VON SCHRENK, in Charge of Mississippi Valley Laboratory.
P. H. ROLFS, Pathologist in Charge of Subtropical Laboratory.
C. O. TOWNSEND, Pathologist in Charge of Sugar Beet Investigations.
P. H. DORSETT, Pathologist.
RODNEY H. TRUE, 6 Physiologist.
T. H. KEARNEY, Physiologist, Plant Breedii
CORNELIUS L. SHEAR, Pathologist.
WILLIAM A. ORTON, Pathologist.
W. M. SCOTT, Pathologist.
JOSEPH S. CHAMBERLAIN, Physiological Chemist, Cereal Investigations.
R. E. B. McKENNEY, Physiologist.
FLORA W. PATTERSON, Mycologist.
CHARLES P. HARTLEY, Assistant in Physiology, Plant Breeding.
KARL F. KELLERMAN, Assistant in Physiology.
DEANE B. SWINGLE, Assistant in Pathology.
A. W. EDSON, Scientific Assistant, Plant Breeding.
JESSE B. NORTON, Asswtantin Physiology, Plant Breeding.
JAMES B. ROREI.,, Assistant 'itf Pathology.
LLOYD S TE^NY ^Assistant in Pathofotft/.
GEORGJ?^. HfcppcoCK, ^sistant in Pathology.
PERLEY SPAULDING, Scientific Assistant.
P. J. O'GARA, Scientific Assistant.
A. D. SHAMEL, Scientific Assistant, Plant Breeding.
T. RALPH ROBINSON, Scientific Assistant, Plant Physiology.
FLORENCE HEDGES, Scientific Assistant, Bacteriology.
CHARLES J. BRAND, Scientific Assistant in Physiology, Plant Life History.
a Detailed to the Bureau of Forestry.
b Detailed to Botanical Investigations and Experiments.
ct
LETTER OF TRANSMITTAL
IT. S. DEPARTMENT OF AGRICULTURE,
BUREAU OF PLANT INDUSTRY,
OFFICE OF THE CHIEF,
Washington, D. <?., September 15, 1903.
SIR: I have the honor to transmit herewith a paper entitled "The
Date Palm and its Utilization in the Southwestern States," and recom-
mend that it be published as Bulletin No. 53 of the series of this
Bureau.
This paper was prepared by Mr. Walter T. Swingle, in charge of the
plant life history work in the Office of Vegetable Pathological and
Physiological Investigations, and was submitted by the Pathologist
and Physiologist with a view to publication.
This Bulletin is the first of a series of life history studies of crop
plants, treating the crop from every possible standpoint and bringing
together all useful information regarding successful cultivation. The
importance of such thorough study and complete treatment of the sub-
ject will be at once apparent. The illustrations, which comprise
twenty-two full-page plates, and ten text figures, are considered neces-
sary to a full understanding of the text.
Respectfully,
B. T. GALLOWAY,
Chief of Bureau.
Hon. JAMES WILSON,
Secretary of Agriculture.
3
343332
P R E F A C E .
The following bulletin by Mr. Walter T. Swingle on the date palm
embodies the results of an investigation of the climatic, soil, and cul-
tural needs of this fruit tree, which he has had the opportunity to
stud} 7 both in the Sahara Desert and in our own Southwest.
It is shown that no heat is too great and no air too dry for this
remarkable plant, which is actually favored by a rainless climate and
by hot desert winds. It is also shown that the date palm can withstand
great quantities of alkalTTn the soil more than any other useful plant.
This demonstration is of special interest now that water has been
brought into the Salton Basin, or Colorado Desert, in southeastern
California, rendering it possible to irrigate some hundreds of square
miles of very rich land where the climate is probably even more
favorable for the culture of the choicest sorts of dates than in the
Sahara. Recent researches of the Bureau of Soils have shown that
a large proportion over half of the soils in the irrigable part of the
Salton Basin is too alkaline to support any ordinary crop. It is shown
in this bulletin that the date palm can be grown without difficulty on
four-fifths of the irrigable lands of this basin, and that on fully one-
quarter of the area it is probably the only profitable crop plant that
can succeed permanently. It will take considerable time, however, to
bring the industry to a paying basis.
The date palm will be of prime importance in many other irrigated
desert areas in the Southwest, where the alkalinity of the soil is too
great to permit the culture of other crop plants. It is, moreover,
confidently believed that date culture, far from being a last resort for
lands unfit for anything else, is one of the most profitable fruit indus-
tries, and that it will pay to plant date palms on the best lands and give
them the most careful attention.
The conditions for the proper utilization of the date palm in this
country have been determined by means of a very careful study into
its life history requirements. This bulletin will show clearly the
importance of life history investigations, of which Mr. Swingle is in
charge. Such investigations are being extended to other important
crop plants.
5
6 PKEFACE.
The work covered by this report has been carried on in cooperation
with the Office of Seed and Plant Introduction and Distribution,
through which all of the important date importations have been made.
The investigations relating to soil conditions have been carried on in
cooperation with the Bureau of Soils.
ALBERT F. WOODS,
Pathologist and Physiologist.
OFFICE OF VEGETABLE PATHOLOGICAL
AND PHYSIOLOGICAL INVESTIGATIONS,
Washington., D. C., August 14, 1903.
CONTENTS.
Page.
Introduction 11
What is the date palm? 13
Date culture by the ancients 17
Propagation of the date palm 18
Seedling palms 18
Seedling date palms for the Salton Basin 18
Propagation of the date palm by offshoots 20
Distances between trees _ 22
Proportion of male trees that should be planted 23
Varieties of male date palms 24
Care to be given date palms .25
The age at which date palms begin bearing 25
Pollination of the date palm 26
Gathering, curing, and packing dates 29
Types of dates and varieties suitable for culture in the United States 30
The three types of dates 30
Varieties of dates suitable for culture in the United States 31
The Deglet Noor date ." 33
The Khalas date 36
Other promising dates ..- 37
The ordinary dates of commerce . 38
Varieties of dates that should be secured for trial in the United States. 38
Introduction of Saharan varieties of date palms into the United States ... 41
The date palm as a shelter for other fruit trees 43
Irrigation of the date palm 44
Amount of water necessary for a date palm 44
Warm irrigation water advantageous 49
Drainage for the date palm 50
Effects of atmospheric humidity and rain on the date palm 52
Rainy weather disastrous to the flowers and ripening fruits of the date
palm : 54
Sunshine necessary for the date palm 58
Heat requirements of the date palm 58
Resistance of the date palm to cold in winter 59
The date palm flowers late in spring and escapes injury by late frosts 61
Drainage of cold air and inversion of temperature in relation to date cul-
ture 61
Hot summers necessary for the date palm 63
Amount of heat required by the date palm in order to mature fruit 65
Effects oi wind on the date palm - 70
7
8 CONTENTS.
Page,
Resistance of the date palm to alkali 72
Investigation of the alkali-resisting power of the date palm in the Sahara. 73
Alkali conditions in relation to date culture at Biskra, Algeria 76
Alkali conditions in relation to date culture at Fougala, Algeria 78
Alkali conditions in elation to date culture at Chegga, Algeria 84
Alkali conditions in relation to date culture at M'rai'er, Algeria 88
Alkali conditions in relation to date culture at Ourlana, Algeria 89
Previous and subsequent analyses of alkaline soils from the Sahara. . . 97
Drainage water from alkaline soils used to irrigate date palms in the
Sahara 98
Alkali conditions in relation to date culture in the Salt Eiver Valley,
Arizona 99
Alkali conditions in relation to date culture in the Sal ton Basin, California. 101
Geography and geology of the Salton Basin 101
Water supply of the Salton Basin 104
Soil conditions in the Salton Basin 106
Alkali conditions at Palm Canyon in the foothills bordering the Salton
Basin Ill
Chemical composition of the alkali of the Salton Basin 112
Fertility of the soils of the Salton Basin 114
Subsidiary cultures to follow in connection with date plantations on alka-
line soils 115
Limits of alkali resistance of the date palm 115
Resistance of the date palm to chlorids 118
Resistance of the date palm to sulphates 119
Resistance of the date palm to carbonates ( black alkali) 119
Regions in the United States where date culture can succeed 122
California 122
Salton Basin or Colorado Desert 122
Death Valley 122
Colorado River Valley 123
Plateau region 123
Interior valley region 123
Coast region of southern California 125
Nevada 4 125
Arizona 126
Salt River Valley 127
Colorado River Valley 129
New Mexico 133
Texas 134
No danger from Mexican competition in date culture 134
Profits of date culture 136
Extent of the market 138
Importance of life history investigations in demonstrating the feasibility of
date culture 139
Summary 141
Description of plates " 142
Index.. 145
ILLUSTRATIONS.
PLATES.
Page.
PLATE I. Old date palms at Hermosillo, northern Mexico Frontispiece.
II. Map of a portion of the Sahara Desert in southern Algeria, showing
principal centers of date culture 76
III. Map showing distribution of soil types and of alkali in the Imperial
area, in the Salton Basin, California 106
IV. Relief map of California, showing the principal regions where dates
can be grown 122
V. Fig. 1. Fruiting date palms at Old Biskra, Algeria, with fig trees
growing underneath, August, 1902. Fig. 2. Date palms at Old
Biskra, Algeria; two large male trees at left 144
VI. Fig. 1. Native gardeners ( Rouara) at Ourlana, Algeria, preparing date
offshoots for shipment by camel back. Fig. 2. Caravan loaded
with date palm offshoots for Arizona, starting from Ourlana north-
ward, May, 1900. Fig. 3. Final trimming of date offshoots at
Algiers preparatory to shipment to America, June, 1900 144
VII. Fig. 1. Flower cluster of male date palm just emerged from sheath
and letting pollen escape. Fig. 2. Three female flower clusters.
Fig. 3. Male and female flowers of the date palm, magnified 144
VIII. Fig. 1. Forest of old date palms at Biskra, Algeria, showing Arab
pollinating flowers. Fig. 2. Arab pollinating a date palm, Ramley,
Egypt, using a rope and broad belt in climbing. Fig. 3. Arabs
demonstrating the pollination of the date palm. Fig. 4. Cluster
of female flowers being tied together to hold the sprig of male
flowers in place 144
IX. Deglet Noor dates from the Sahara Desert, natural size. Photo-
graphed at Washington two months after being picked 144
X. Deglet Noor dates packed for the retail trade 144
XI. Date palms growing in basin irrigated by flooding at Bedrachin, near
Cairo, Egypt. September, 1902 144
XII. Fig trees growing under partial shade afforded by date palms, oasis
of Chetma, Algeria 144
XIII. Arab climbing tall palm in a garden at Biskra, Algeria, to pollinate
the flowers. May, 1900 144
XIV. Fig. 1. Date palms growing without irrigation near Fougala,
Algeria. Fig. 2. Shallow well used to irrigate date palms at
Fougala, Algeria 144
XV. Fig. 1. Very alkaline undisturbed Saharan soil at Fougala, Algeria;
young palms growing in pits. Fig. 2. Date palm in diseased con-
dition called "ineznoon," Fougala, Algeria *. 144
XVI. Fig. 1. Young date palms growing on very alkaline soil at Chegga,
Algeria. Fig. 2. Young date palms and alfalfa at Chegga, Algeria. 144
9
10 ILLUSTEATIONS.
Page.
XVII. Fig. 1. Date plantation on alkaline soil at Ourlana, Algeria. Fig. 2
Crescent-shaped excavation at the base of a date palm to hold irri-
gation water, Biskra, Algeria 144
XVIII. Fig. 1. View in the Salton Basin, near Imperial, Cal., showing level,
bare desert soil. Fig. 2. Shore of a dry salt lake, Chott Merouan,
between Chegga and M'raier, Algeria 144
XIX. Fig. 1. A neglected Egyptian date palm growing without irrigation
in the Salton Basin, near Indio, Cal. Fig. 2. Old date palms
at Hermosillo, northern Mexico, with orange trees growing under-
neath. Fig. 3. Fan palm showing dead leaves clothing trunk,
near Indio, Cal. Fig. 4. Group of fan palms growing wild in a
dry ravine, near Indio, Cal 144
XX. Old date palms growing at San Diego Mission, near San Diego, Cal.
Fig. 2. Seedling date palm with nearly ripe fruit, growing with-
out irrigation in the flood plain of the Colorado River in California .
XXI. View in cooperative date orchard, Tempe, Ariz., showing offshoots
imported from North Africa in 1900 144
XXII. Three-year-old Deglet Noor date palm in fruit, growing in the
cooperative date orchard at Tempe, Ariz. , from an offshoot imported
from the Sahara Desert, in July, 1900. Photographed August,
1903 144
TEXT FIGURES.
FIG. 1. A young Deglet Noor date palm at Biskra, Algeria 16
2. Date flower cluster after artificial pollination 27
3. Wolfskill dates grown at Winters, Cal 31
4. Bennett date from Phoenix, Ariz 32
5. Deglet Noor dates from the Algerian Sahara, showing methods of
packing for retail trade 34
6. Cooperative date orchard at Tempe, Ariz 42
7. Curves representing the average maximum, mean, and minimum tem-
peratures at Salton, Cal. , and Biskra, Algeria 64
8. Sunken date gardens in the sand dunes in the Oued Souf region near
El Oued, Algeria 69
9. Curves showing the distribution of alkali to a depth of 4 feet in uncul-
tivated Saharan soil, Station No. 1 , Fougala, Algeria 81
10. Sketch map showing the Salton Basin and the easily irrigable lowlands
in the Colorado Eiver Valley, in Nevada, Arizona, and California. . 102
B. P. I. 73. V. P. P. I. 106.
THE DATE PALM AND ITS UTILIZATION IN THE SOUTH-
WESTERN STATES.
INTRODUCTION.
The purpose of this bulletin is to call attention to the peculiar
suitability of the date palm for cultivation in the hottest and most arid
regions in the Southwestern States and to its remarkable ability
to withstand large amounts of alkali in the soil. The most intense
heat, the most excessive dry ness of the air, the absence of all rain-
fall for months at a time during the growing season, and even the
hot, dry winds that blow in desert regions are not drawbacks, as in
almost all other cultures, but positive advantages to the date palm,
enabling it to mature fruit of the highest excellence.
The growing of the best sorts of dates where the climate is favora-
ble promises to be more profitable than any other fruit culture pos-
sible in such regions, and this industry would long ago have been
carried on extensively had the climatic and soil requirements of this
plant been better known, and had there not been general ignorance as
to the methods of propagation, as well as a lack of the best sorts to
propagate.
The date palm has the unusual power of resisting large amounts of
alkali, the most dangerous foe to agriculture in the arid regions, both
in the soil and in the irrigating water. This will permit it to be grown
profitably on lands so salty as to prevent the culture of any other pay-
ing crop, and thereby render feasible the reclamation of hundreds of
square miles of the most fertile lands in the Southwest which, at great
expense, have been put under irrigation.
Thanks to the hearty cooperation of Prof. Milton Whitne} r , Chief
of the Bureau of Soils, it has been possible to investigate thoroughly
the ability of the date palm to withstand alkali in the soil. Samples
of soils were selected by the writer in date plantations in the oases in
several different regions in the Sahara Desert (see map, PI. II, p. 76)
with especial reference to a determination of the effect of alkali on the
growth and f ruitf ulness of the date palm. Analyses of these soil sam-
ples, made by Mr. Atherton Seidell, were placed at the disposition of
the writer by Professor Whitney, and have rendered it possible to
11
12 THE DATE PALM.
determine with some degree of accuracy the alkali resistance of this
remarkable plant, which important point in its life history is here
considered in detail for the first time.
One of the principal reasons for publishing this bulletin is the com-
pletion of a system of canals which will irrigate a considerable portion
of the Salton Basin, a or Colorado Desert, in southeastern California,
from the Colorado Eiver, some 60 miles away. Water was first
brought in, after great expense had been incurred and no inconsider-
able engineering difficulties overcome, in June, 1891, and since then
the development of the new country has been very rapid. Before the
end of the year 1891 some 125,000 acres of this land had been taken
up. This desert lies mostly below sea level and is characterized by
having the hottest and driest climate known in North America.
As soon as water was put on it was evident that some of the land
was alkaline, and researches made by the Bureau of Soils of the
Department of Agriculture 6 have shown that over half the lands now
irrigable are too salty to permit the culture of any but alkali-resistant
plants. Probably one-fourth of these lands will not support perma-
nently any other profitable crop than the date palm. Now, it happens
that the climate of this desert is better adapted than that of any other
region in North America for the culture of the best sorts of dates and
is even better than that of the northern part of the Sahara Desert,
whence are exported the choicest dates that now reach the markets of
Europe and America. The advantages of this region over any others
in the United States or Mexico for the growing of the best late varie-
ties of dates, such as the Deglet Noor, are so great as to give it almost
a natural monopoly of the production of these dates, the most expen-
sive dried fruit on our markets.
In the United States the term "desert" is applied only to unirrigated or unculti-
vated arid regions, and as fast as such areas are reclaimed and put to profitable cul-
ture by means of irrigation they cease to be called deserts and receive some other
name. The appellation ' ' desert " is a hindrance to real-estate transactions and is
felt to be unjust and opprobrious by those who live in the midst of flourishing fruit
orchards and alfalfa fields. Doubtless the same change of name will take place in
case of the Colorado Desert, and indeed the misleading term " Colorado delta" has
already been applied to the newly irrigated lands about Imperial and Calexico. The
true delta of the Colorado Eiver lies to the southward, where this stream enters
the Gulf of California. The region in question might very appropriately be called
the Salton Basin, inasmuch as it is a true basin, an area surrounded on all sides by
mountains or higher lands and depressed far below sea level in the center, where
its most prominent topographical feature, Salton Lake or Salton Sink, is located.
Throughout this bulletin Salton Basin is used instead of Colorado Desert to desig-
nate the lower parts of the lands sloping toward Salton Lake, a region limited on
the north by the San Bernardino Mountains, on the west by the San Jacinto Moun-
tains, and extending southward into Mexico to the line beyond which the delta lands
slope toward the Gulf of California.
6 Means, Thos. H., and Holmes, J. Garnett. Soil Survey around Imperial, Cal.
Circular No. 9, Bureau of Soils, U. S. Dept. of Agriculture, 1901.
INTRODUCTION. 13
There exists, therefore, tin unusuai combination of circumstances, in
that the opportunity for introducing a most profitable new industry
into this region coincides with the pressing needs of a new country
for some crop which can withstand alkali.
The resistance of the date palm to alkali is so much greater than that
of other crop plants that it will be indispensable for the more alkaline
areas through the Southwest wherever the climate is hot and dry enough
to permit even the less valuable early sorts to mature. Already date
palms are being planted on alkali lands in the Salt River Valley,
Arizona, and as a result of the demonstration of the feasibility of
growing them the price of such land has more than quadrupled within
the last five years. Doubtless within a decade date culture will be
much extended in Arizona, and it probably will become the most
important fruit industry in the Salton Basin in California.
It becomes a matter of great importance to show what the climatic
requirements of the date palm are and to determine how much alkali
it can withstand, as well as to indicate how date palms are propagated
and how their culture is carried on. This exposition is especially
necessary in case of this plant, as its needs as to climate and soil arc
unlike those of any other plant commonly grown, and the methods
followed in its propagation and culture are widely different from those
employed for other crop plants.
It is believed that these data, here presented in detail, a will serve to
facilitate the establishment and the extension of a new industry in this
country.
WHAT IS THE DATE PALM?
The date palm was one of the first plants to be cultivated, and has
been grown for at least four thousand years along the Euphrates and
Tigris rivers. It has been for ages and is still the most important
food plant of the great deserts of the Old World, and many regions in
Arabia and in the Sahara would not be habitable were it not for this
tree. Not only does it yield a delicious fruit of great food value, but it
also furnishes in many regions the only timber suitable for use in the
construction of houses and for making a thousand and one necessary-
objects. Its leaves furnish a partial shade, under which it is possible
to cultivate other fruit trees which could not exist were they exposed
to the direct rays of the sun and the burning winds in the desert;
thousands of fig, almond, pomegranate, and peach trees and grape-
vines, forming veritable orchards, are cultivated in the palm- covered
oases, especially in the northern Sahara. For centuries the transporta-
tion of dates has been the chief motive for the formation of the great
Many of the facts here presented were summarized by the writer in a previous
article, entitled "The date palm and its culture," Yearbook of the Department of
Agriculture, 1900, pp. 453-490; also reprinted.
14 THE DATE PALM.
caravan routes which run in every direction through the deserts in
Africa and Arabia. The exportation of dates to Europe and to America
is an important industry both in North Africa and in the countries
bordering the Persian Gulf.
The value of the dates imported into the United States alone
averaged for the ten years ended June 30, 1900, $402,762 per annum,
as appraised at the exporting point, but the real value when received
at the American port was doubtless 50 per cent greater, or $600,000 a
year. This value is now exceeded only by the imports of two other
dried fruits Zante currants, $916,908 in 1900, and Smyrna figs,
$513,895, in 1900. Inasmuch as California has been producing large
quantities of second-class dried figs for some years, and since 1900
also Smyrna figs of the best quality, a it is likely that in the near
future the value of the imports of figs will fall below that of dates,
which will then rank second in value among imports of dried fruits.
The date palm, as its name indicates, belongs to the great family of
palms. Like the majority of its relatives, it has but a single bud at
the top of the trunk, and if this bud be destroyed the tree usually
dies. The date palm, however, unlike the cocoanut palm and unlike
the majority of palms, produces offshoots, or " suckers," at the base
of the stem (see PI. XVII, fig. 2, and Yearbook, 1900, PL LIX, fig.
4), & at least during the first decade of its existence. Old date palms
which are in full bearing do not produce such offshoots, and if the
terminal bud be destroyed the whole plant will die. since offshoots
are very seldom, if ever, produced at the top of the trunk. The date
palm, like most other members of this family, has a trunk which
remains of the same diameter, no matter how old it may be, there
This gratifying result was brought about by the introduction of the fig insect
(Blastophaga), which the writer accomplished in the spring of 1899 by sending from
Algeria the winter galls of the male fig tree containing these insects. The Blastophaga
fertilizes the flowers of the Smyrna type of figs, which, unlike ordinary figs, do not
set fruit unless pollinated. The large orchard of Smyrna figs at Fresno, Cal. , belong-
ing to Mr. George C. Eoeding, which had produced but a few dozen figs pollinated by
hand during the twenty years it had been planted, began to yield abundant crops as
a result of the introduction of this beneficent insect, and in 1901 produced some
70 tons of dried figs. The success of this orchard has led to a renewed interest in
fig culture, and several other large plantations have been set out near Fresno, while
many orchards of inferior varieties are being grafted to the Smyrna fig.
& Throughout this bulletin references have been made to plates published by the
writer in his paper, "The date palm and its culture," in the Yearbook of the
Department of Agriculture for 1900, pp. 453-490, Pis. LIV-LXII. This publication
is accessible in all libraries, and it has been arranged to send a reprint of the paper
with the present bulletin to all applicants in the Southwest who live in regions where
date culture is feasible. This will render it possible for all interested to refer to the
plates in this previous paper. In order to shorten the references to these plates
they are cited as "Yearbook, 1900," with the number of the plate. Inasmuch as the
plates of this Yearbook article were numbered from LIV to LXII and those of the
present bulletin are numbered from I to XXII, confusion is impossible.
WHAT IS THE DATE PALM? 15
b'eing no secondary increase in diameter with increasing age such as
occurs in ordinary fruit and forest trees. In consequence, the age of
a palm tree can be roughly estimated from its height, but never from
the diameter, nor, as is customary among woodsmen, by counting the
rings of annual growth, for the simple reason that the date palm has
no such rings.
The leaves of the date palm (frontispiece and fig. 1, p. 16) are
feather shaped and very large, frequently from 12 to 18 feet long.
The ancient Egyptians had a tradition, held also by some tribes of
modern Arabs, that the date palm produces twelve leaves in a year.
It is an interesting fact that the Egyptian hieroglyphic which signified
a month represented a single leaf of the date palm, and the sign for a
year pictured a crown of leaves of the date palm. a Of course, there is
no such fixed interval of time between the unfolding of successive
leaves, but it is true that the date palm usually produces from twelve
to twenty leaves in a year.
These leaves remain alive and green for several years, but finally
lose their color and bend downward toward the trunk. (See the lower
leaves on the tall palm in PL XIX, fig. 2.) Travelers who have
seen date palms growing remote from human habitations in the Sahara
Desert report that in such situations the old leaves remain attached to
the trunk permanently, the palm being crowned with living green
leaves and the trunk clothed to the ground by the reflexed dead leaves.
Furthermore, in such conditions, where the date palm is left to grow
uncontrolled by man, the offshoots produced by the young palms grow
unhindered and often rival in size the parent trunk, and they in turn
give rise to other offshoots, even after the parent stem has passed
the age when it would produce offshoots. The result of this is that
instead of a single palm tree, the traveler sees a great thicket com-
posed of a few tall trunks (the original palm and the oldest offshoots),
surrounded at the base by a tangled mass of younger offshoots, strug-
gling upward and outward. Such a clump is shown in Yearbook, 1900
(PL LIX, fig. 4). All of these trunks retain their dead leaves per-
manently, so that such a clump of palm shoots is well nigh impen-
etrable. To those who have traveled in countries where the date
palm is the commonest cultivated tree, the description given above
will seem very strange. In all such countries the date palm is well
cared for and the dead leaves removed, leaving a clean trunk, crowned
with a tuft of living leaves. (See frontispiece and Yearbook, 1900,
PL LX.) Besides this, the Arab cultivators are careful to remove the
offshoots as soon as they are large enough to plant, or to destroy them
when young in case they do not desire to propagate the variety. Such
Fischer, Th. Die Dattelpalme, Erganzungsheft No. 64. In Petermann's Mit-
theilungen. Gotha, 1881, p. 4.
16
THE DATE PALM.
offshoots, ready to remove, are shown on Plate XVII, figure 2, and
offshoots removed and ready to transplant on Plate VI, figure 3.
Unlike most fruit trees, the date palm has the male and the female
flower on separate individuals. If grown from seed, about half of the
resulting palms are male and about half female. If such trees be
allowed to grow to maturity in this proportion enough pollen is blowr
by the wind to fertilize all the flowers properly. It would be, how
ever, a very expensive method of culture to irrigate and cultivate suet
a large proportion of male trees. The Arabs and before them the
FIG. 1. A young Deglet Noor date palm at Biskra, Algeria; below a " flower cluster just opening
above two young fruit clusters, the larger still bound about with the cord used to- attach the mal
flowers in pollinating. May, 1900. (After negative by the writer.)
Assyrians learned to pollinate the palm artificially, and from a smal
proportion of male trees to fertilize the flowers of a very great numbe
of female trees. At the present time the proportion followed in com
mercial planting is that of about one male tree to a hundred femal<
trees.
The date palm blooms in the early spring, producing from six t<
twenty flower clusters, according to the age and vigor of the tree (se<
fig. 1). Each flower cluster on the female tree produces a bunch o
DATE CULTUTE HY THE ANCIENTS. 17
dates, consisting of numerous fruits, borne on slender twi^s, which
branch from a main stalk (PL XXII and Yearbook, 1900, PL LX).
Such a bunch may bear from 10 to 40 pounds of dates, and a vigorous
tree is commonly allowed to produce from eight to twelve such bunches.
The date itself is, of course, familiar to everyone; it is an oval fruit
from 1 to 3 inches long, and one-half or one-third as wide, containing
a single seed surrounded by a half dry and very sweet pulp, usually
amber colored. There are very many varieties of dates, differing
widely as to character and quality, as will be explained more in detail
farther on.
DATE CULTURE BY THE ANCIENTS.
The date palm is one of the oldest cultivated plants. It is fully
described on the clay tablets of the ancient Assyrians. It was undoubt-
edly one of their most important food plants, and every detail of its
culture, the operation of pollinating the flowers, and even the serving
of the fruit at the tables of the wealthy were delineated with great
accuracy on their monuments and wall sculptures. It is probable that
the date palm was first extensively grown in the valle} T s of the
Euphrates and Tigris rivers. It was apparently little known and but
slightly esteemed in ancient Egypt before 3000 B. C., although as
early as 2000 B. C. it had already become a well-known fruit tree.
Not much is known as to the origin of the date palm, although every-
thing points to its being native in some of the ravines bordering the
deserts of northern Africa or Arabia. It is probable that it was first
cultivated by the Assyrians, afterwards by the Egyptians, and that
very early its culture became almost a national indust^ with the
Arabs. It is true that the date palm existed in ancient Africa before
the arrival of the Arabs. It was, however, comparatively unimportant,
at least in the western Sahara, and the varieties were probably infe-
rior. When the Arabs invaded the western Sahara and the Barbary
States during the seventh century, and at various intervals until the
twelfth century, they introduced the use of the camel and thereby
rendered it possible for the inhabitants of the oases to satisfy all their
wants, simply by growing an abundance of dates, since the camels
could carry the dates to the more fertile regions bordering the Medi-
terranean, where they could be exchanged for the wheat and barley
needed in the Sahara for making bread. In consequence of this eco-
nomic revolution, the culture of the date palm speedily became, and is
still, the most important interest throughout the Sahara Desert.
The Moors undoubtedly introduced the date palm into Spain, where,
in spite of the unfavorable climate, it was extensively planted during
the Saracen domination. The first date palms in the New World were
grown from seeds carried from Spain by the missionaries who accom-
panied the Spaniards on their voyages of discovery and conquest,
13529 No, 5304 2
18 THE DATE PALM.
PROPAGATION OF THE DATE PALM.
SEEDLING PALMS.
Date palms may be grown from seed and are generally so grown in
Mexico and in India, but if so propagated something over half the
palms are males, which produce no fruit whatever, while of the remain-
ing female plants probably, on the average, not more than one in ten
produces good fruit. This would mean that in planting 100 seeds,
on the average only four or five palms bearing good dates would be
secured and probably as many more of second quality, or in all some
10 per cent of the number planted would yield edible fruit. It should
be said that in Arizona, and even in Mexico, very many of the seed-
ling sorts do not reach maturity because of the insufficient summer
heat; but if grown in the Sal ton Basin, where all the sorts could
mature, a larger proportion, possibly 15 per cent, would produce fruit
that could be used.
SEEDLING DATE PALMS FOR THE S ALTON BASIN.
In view of the scarcity of offshoots of the best varieties and the press-
ing need for date palms for many parts of the Salton Basin, it would
be well worth while to plant orchards of seedlings, and when they are
in bearing the worthless sorts could be cut out and their places gradu-
ally filled by taking offshoots from the seedlings yielding good fruit.
It would be possible to begin thinning out the excess of males as
soon as the flowers begin to show, some four to six years aftei-jplant-
ing. The trees could be planted, say, 12 feet apart, in rows 25 feet
apart, giving about twice the number that should be left, because
nearly half the total number will prove to be males, to be cut away as
soon as recognized. By the sixth or seventh year after planting the
quality of the fruit produced by the female plants could be judged and
the plants producing the poorest dates could be removed and replaced
by offshoots from the best seedlings, which should, of course, be planted
where the rows show the largest gaps, resulting from the removal of
superfluous males and worthless females. In the course of a few years
it would be possible to remove all the less valuable seedlings and
replace them with the better sorts. This process could go on indefi-
nitely by continually replacing poorer sorts with better as fast as off-
shoots were available, until only two or three of the best sorts remained.
No outlay would be entailed for offshoots, and if considerable numbers
of seedlings were grown from the best dates there certainly would be
some sorts of value among them.
If any attempt be made to start seedling date orchards in the Salton
Basin it should be borne in mind that the young seedling can not with-
stand nearly as much alkali as can offshoots or old palms. Prof. R. H.
Forbes a finds that many of the .young plants grown from seeds which
a Oral communication to the writer, 1902,
SEEDLING PALMS. 19
had been planted at the Cooperative Date Garden at Tempe, Ariz. , were
killed by alkali shortly after they appeared, while the offshoots grow-
ing near by were unharmed. In case alkaline areas are to be planted
it would be best to establish a nursery on alkali-free land and trans-
plant the seedlings when the}^ are 1 or 2 years old, or, if the soil is very
alkaline, when 3 or 4 years old, to the positions they are to occupy
permanently. Where the palms are to be planted on the very worst
alkaline lands it would be well to allow the young date palms to flower
in the nursery rows, so that the males could be discarded and only
females set out, with the precautions for washing out the alkali men-
tioned below, thus avoiding the expense and trouble of caring for the
worthless male plants. It is easy to distinguish the male from the
female plants by an inspection of the flowers, which, as is shown in
Plate VII, figure 3, are very different in the two sexes. In transplant-
ing young seedlings the leaves should be cut back severely to corre-
spond with the cutting back suffered by the root system.
It is interesting to note in this connection that the date palm requires
for its germination not 'only fresh water, free from any considerable
amount of dissolved alkali, but also a large and continuous supply of
such water. The young seedling shows curiously enough a whole set
of peculiarities of structure which enable it to throw off an excess of
moisture. Fritsch, an Austrian botanist, concluded that the seed was
adapted for germination during the rainy season, and that it was
meant to grow in earth thoroughly saturated with water." Not only
are the roots devoid of hairs, resembling in this peculiarity those of
plants which grow in swamps and in water, but they have numerous
aerating canals, and in other wa} 7 s show adaptation for growth in very
moist situations. There are even pores at the tops of the leaves by
which the little seedlings can get rid of superfluous moisture which
has been absorbed by the roots.
Seedling dates are nearly always found along irrigating canals or in
situations where the earth is kept constantly moist. These are strong
indications of the natural habitat of the date palm, which should be
expected to grow where the earth is very moist, at least during the
rainy season. It is practically impossible for date seedlings to start
in unirrigated arid situations, even where cacti and other desert plants
grow abundantly.
As is clear from what has been said, the date does not reproduce true
to t}'po from seed. This may be in part because no attention has been
paid to the pedigree of the male plants used to furnish pollen, so that
even the choicest dates may have been pollinated from males of the
most worthless character. If it should be found desirable to plant
seedling orchards it would be well to arrange to have Deglet Noor
a Fritsch, G. Anatomisch-physiologische Untersuchungen iiber die Keimung der
Dattelpalme, in Sitzungsb. d. k. Akad. d. Wiss. Wien, Bd. 93, Abth. I, April, 1886.
20 THE DATE PALM.
dates pollinated from a number of trees in the hope that some of these
males would produce seedlings of a superior type. If possible males
known to be seedlings of the Deglet Noor or of some other superior
sort should be employed in such pollination. It is wortlry of note
that the male dates in California, and especially those in the Salt River
Valley, Arizona, are for the most part the offspring of fairly good soft
dates, probably from the Persian Gulf region, purchased in the markets.
So Arizona and California dates would be well worth planting, since
both parents of the seeds in such dates are the offspring of soft dates,
whereas in most regions where the date palm is grown the males are
likely to be the product of dry dates (for most of the dates in those
countries are of the dry type) dropped by chance in a wet spot where
they could grow.
The seedlings of a single sort of date may present the most remark-
able variations, and usually the parent type is not exactly reproduced
by any of the offspring. This is clearly shown by the experiments of
Col. Sam Taylor, of Winters, Cal., who tried to propagate from seed
the valuable early ripening Wolf skill date growing on his place. This
was done because this palm had ceased to produce offshoots before its
value was recognized. Many of these seedling dates have fruited, but
none resembles in the slightest degree the parent variety; most of them
are much later and consequently fail to mature at Winters, where the
summer heat is insufficient to ripen any but the earliest sorts.
PROPAGATION OF THE DATE PALM BY OFFSHOOTS.
In all regions where its culture is an important industry the date
palm is almost invariably propagated by removing and planting the
offshoots or suckers which spring up around the base of the trunk (PL
XVII, fig. 2, and Yearbook, 1900, PL LIX, fig. 4). These offshoots
reproduce the parent variety exactly and have the great advantage of
coming into bearing sooner than seedlings. Offshoots are produced
abundantly by young date palms, but cease to form when the trees
reach the age of 10 to 15 years. Usually three or four are left
attached to the parent plant, any in excess of this number being cut
away as fast as the} 7 form. One offshoot can be removed every year
until they cease to be produced. They are cut away from the parent
trunk when the} 7 are from 3 to 6 years old, after they have begun to
develop roots, if as usual they start from below the surface of the
ground and have their bases covered with earth. The leaves are all
cut away, leaving only the bud in the center protected by the leaf-
stalks (PL VI, fig. 3). No roots are left attached to the offshoot,
which, when so reduced to a mere stump, can stand much exposure.
Some offshoots procured by the writer on May 18 and 19, 1900, at
Ourlana, Algeria, in the Sahara Desert, were shipped by camel-back
PROPAGATION BY OFFSHOOTS. 21
(PL VI, fig. 2) to Biskra, !>:> miles away, and from there to Algiers,
some 390 miles by rail, with no packing except a little palm fiber
about the bases. One box of these offshoots was packed in straw
with no moisture whatever except from having been wet twice, once
at Biskra and once at Algiers. So packed they were sent to New
York by steamer, arriving July 3, then transshipped to New Orleans
and finally carried by rail from New Orleans to Tempe, Ariz., where
they arrived July IT. They were unpacked July 20, two months after
they had been dug up. Prof. R. H. Forbes, under whose personal
supervision the palms were planted and cared for, reports that the
box of offshoots which had no packing other than the loose dry straw
came through as well as those packed in damp moss or in charcoal.
Some 80 per cent of these suckers lived. a
It is very important that the offshoot be planted out high enough so
that the growing bud in the center is never in danger of being covered
with water when irrigated. (See fig. 6, p. 42.)
In order to force the offshoots to take root and grow, the chief requi-
site is that the ground be kept constantly wet about their bases. If
the young plants dry out once they are lost, for the delicate new roots
that are just forming will be killed. The Arabs water the offshoots
every day for the first forty days after planting and then twice a
week until winter, after which they are watered as often as may be
necessary to keep the ground thoroughly moist.
Another requisite almost as important as the keeping of the base of
the plant moist while roots are starting is that the ground be warm
when the offshoots are transplanted. It is useless to set out offshoots
in autumn or winter; the best season is late in spring or early in
summer, when the ground is thoroughly warm and when there is a
long hot season after planting, permitting the young palms to become
well established before winter. It is not necessary to shade the young
offshoots, but they should be protected against cold during the first
winter after being set out, by wrapping with burlap, heavy paper, or
straw.
Professor Forbes finds (see p. 10) that young seedlings are often
killed by alkali where offshoots and old palms grow all right. Strong
alkali is probably injurious also to offshoots just striking root,
and the following method of preventing the rise of alkali, communi-
cated })y Professor Forbes, may be advantageously followed in all
cases where there is danger to be apprehended from this source:
Throw up a high border on each side of the rows, running in both
directions, thus creating a square inclosed space about each palm.
This space ma}^ be flooded from the irrigating canals with fresh water,
which carries away the salts accumulated near the surface down to
Forbes, R. H. Twelfth Annual Report, Arizona Experiment Station, p. 317.
22 THE DATE PALM.
lower level beyond the reach of the young roots. The area about the
ofl'shoot inclosed by the borders should then be covered with straw to
a depth of a foot. This mulch will hinder evaporation and thereby
restrict the rise of alkali, since each application of water washes the
alkali down anew and the mulch continues to act as a check on evapo-
ration. Such a method of planting should be adopted in those parts
of the Salton Basin where there is danger of a rise of alkali from the
subsoil.
DISTANCES BETWEEN TREES.
The Arabs almost invariably plant the date palm without any attempt
at placing the young ofl'shoots in definite order. The result is, it is
almost impossible for them to be sure of planting the trees at any con-
stant distance from each other, some being close together, others wide
apart, as can be seen in Plates XII and XIII.
The unsystematic and frequently careless methods employed by the
Arabs in the culture of the date palm can not be taken as models to be
followed in introducing the date industry into the Southwest; we should
rather follow the example of the French colonists in the Sahara, who
plant the date palm in regular rows (see PL XVII, fig. 1), and have,
as a rule, definitely planned and carefully executed systems of irriga-
tion and drainage. Although the Arabs plant the date palms very
close together, the French have found it advisable to place the trees
wide apart, and many of the French colonists regret having placed
the trees only 20 or 22 feet apart, their opinion now being that date
palms should be planted from 26 to 33 feet from each other.
Ben Chabat, an Arab, who is considered an authority on date cul-
ture, makes two date palms speak together; one says to the other,
" Take thy shadow away from mine and I will produce alone for us two
together" expressing the idea that too close planting is dangerous.
At 26 feet apart, which may be taken as an average distance, about 60
palms would be planted on an acre. If the palms are put 30 feet or
more apart other crops can be grown between the trees even when old.
The amount of irrigation water available during the hot season and
the value of land are factors which must be considered in deciding
at what distance the offshoots should be planted. In general the far-
ther apart the palms are, the more heat and light each receives, and
the better and the more abundant is their fruit.
Even when planted 26 feet apart or less there are, of course, large
strips which lie unused between the palm trees for the first ten or
twelve years after planting. It has become a common practice in the
Algerian Sahara, copying to some extent after the Arabs, to plant
garden or field crops between the trees until the palm trees become
large enough to shade the ground. In case the soil is alkaline, it is
"Masselot, F. Bui. Direction Agric. et Comm., Tunis, vol. 6 (1891), No. 19,
PROPER PROPORTION OF MALE TREES. 23
f requently impossible to grow any crop until two or three years of
abundant irrigation, coupled with a good system of drainage, have
washed the alkali out of at least the top layers of the soil. Barley is
usually the first crop grown on alkaline soil. After barley has been
grown a year or two, the abundant irrigation being, of course, kept
up, the land usually becomes freed from alkali sufficiently to permit
horse beans, cowpeas, beets, and other garden crops, and, what is of
more importance, alfalfa, to be grown. This Saharan alfalfa (see PL
XVI, fig. 2), although refusing to grow on soil which produces a fair
crop of barley, is, nevertheless, able to withstand without injury a
percentage of alkali in the soil which would prevent the growth of
ordinary alfalfa."
PROPORTION OF MALE TREES THAT SHOULD BE PLANTED.
It has been found in the date plantations of the Sahara that for
every hundred date palms there should be at least one male tree to fur-
nish pollen for use in fertilizing the flower clusters in spring. There
is already a large number of male date palms in Arizona and Cali-
fornia, so that it has not been thought necessary to introduce more
than a very few from the Old World. The ratio of one male for every
hundred female palms applies only in the Sahara, where it is possible
to secure male palms known to flower at the right time to be used in
pollinating. It often happens that many of the seedling male plants
flower too late to be of any use. b It does not interfere so much with
the usefulness of a male date palm to have it bloom too earty, since
the bunch of male flowers can be preserved for some weeks without
serious deterioration. In view of these facts it will be advisable in
starting any plantations to put out at least one male palm for every
fifty females, or better, one male for every twenty-five females. It
will be desirable also to secure offshoots from different male trees in
order to avoid getting male trees all of one kind, which might be
found to bloom at the wrong season. In case no offshoots of male
trees can be secured, a few seeds may be planted and the male palms
saved to furnish pollen. When the trees begin to flower it will be possi-
ble to see readily which male trees flower at the right season; the
others can be destroyed and offshoots from female trees planted in
their places.
After much correspondence with the Arab caids in the interior of the Sahara, a
small quantity of the seed of this valuable alfalfa was obtained for the writer in the
spring of 1901. It is earlier than ordinary alfalfa and resists heat and alkali better.
It has been planted in the Cooperative Date Garden at Ternpe, Ariz., and it is hoped
that it will prove as valuable in the Southwest as it is in the Sahara.
& Out of six date palms which had flowered up to 1898 at the San Joaquin Valley
substation of the California Experiment Station, three were female and three male,
but two of the male palms did not flower until the female trees had ceased blooming.
24 THE DATE PALM.
VARIETIES OF MALE DATE PALMS.
Some male trees produce more pollen than others, and are much
preferable to use in pollinating. When once good sorts of males are
found they should be propagated by offshoots in the same manner as
the female plants. In most parts of the Algerian Sahara no particular
attention is paid to the propagation of suitable male palms, and in
consequence pollen is sometimes scarce early in the flowering season
and again later on, which often renders it necessary to procure pollen
from neighboring orchards or even from other oases, sometimes at
considerable trouble and expense. In Tunis there is a male variety
propagated by offshoots called the Deglaoui used to pollinate late-
blooming sorts. Another called the Dakar majahel was secured by
Mr. D. G. Fairchild in Egypt, and has been sent to the Cooperative
Date Garden at Tempe, Ariz. It is said to be the only male palm
which produces pollen at the right time to be used on all of the eight
varieties of female dates grown about Ramley, Eg} r pt.
The chief requisite of a male date palm is that it shall produce an
abundance of pollen at the right time to be used in pollinating the
female sorts that are grown. If date palms were propagated from
seed, and still more if any attempt should be made to breed new and
better sorts, it would be very desirable to secure male sorts capable of
transmitting desirable characteristics to their offspring. (See p. 20.)
Schweinf urth has recently put forth the claim a that the male sort
used for pollinating the flowers has a decided influence on the shape
and, what is more important, on the size of the seed of the dates which
result. If this were true it would be very important to secure male
sorts which when used for pollination would produce small seeds.
Schweinfurth's supposition is, however, without doubt erroneous, for
in spite of his assertion that the observed variability of the seed in
dates of the same variety b is a proof of the effect of the different sorts
of pollen used to fertilize the flowers, the fact is that the seeds of any
one sort are so uniform in size and shape as to furnish good characters
for use in distinguishing varieties, and are regularly so employed by
both Europeans and Arabs. The only part of the seed which could
be affected directly by the male parent is the embryo, which in the
date occupies so small a fraction of the bulk of the seed that it is not
surprising that there is no observable effect of the pollen on the seed
and much less on the pulp which surrounds it.
a Schweinfurth, Dr. Georg. Ueber die Kultur der Dattelpalme. In Gartenflora,
vol. 50, 1901, p. 513.
& Naturally the seeds are not all exactly alike, even on the same tree, and some
varieties of dates have seeds which vary appreciably in shape and even in size; but
this range of variation is itself a varietal character. Of course the incorrect identifi-
cations of dates often made offhand by the Arabs may easily lead to erroneous ideas
as to the extent of variation in a sort through a confusion of varieties similar in
external appearance, but differing in seed characters.
CARE TO BE GIVEN TREES. 25
Male date palms generally have stouter trunks and more leafy
crowns than female trees (see PL V, fig. 2), arid some have said that
even the young plants could be distinguished a matter of much im-
portance where dates are propagated from seed, when it is desirable
to recognize and destroy as soon as possible the superfluous male
plants. It has not been found possible to depend on any of the signs
given for distinguishing young male plants, and they can be recognized
with certainty only when they are in flower. An inspection of figure
3 on Plate VII will show how different the male flowers are from the
female and render it easy to determine the sex of the palms as soon
as they show flowers.
CARE TO BE GIVEN DATE PALMS.
The chief care required by date palms is that they be irrigated as
often as needful. The soil should be kept in a proper state of tilth,
which is usually done by growing some crop between the rows, espe-
cially when the palms are young. The leaves are trimmed off as they
die, and care is taken not to allow too many offshoots to grow at the
base of the stem, for they draw on the strength of the parent plant.
In general not more than three or four offshoots should be allowed to
grow at once. At least one should always be left attached to the
mother plant to be used to replace it in case of accident. a
Old palms, ten to fifteen years after planting, which have developed
a good trunk 4 to 10 feet high, do not produce offshoots, and such trees
require no attention other than the cutting away of the dead leaves,
the pollination of the flowers, and the gathering of the fruit.
THE AGE AT WHICH DATE PALMS BEGIN BEARING.
The age at which palms come into bearing depends much upon the
climate and soil; where planted in rich soil, watered abundantly, and
where the summer heat is intense and long continued, the date may
begin to fruit when very young. Trees have been known to bear in
Arizona within four years after the seed was planted; however, such
palms are too small to bear more than a very few fruits, and seedling
trees are generally considered not to yield paying quantities of fruit
until they are at least 6 or 8 years old (see Yearbook, 1900, PL LVII,
fig. 1). When date culture is practiced scientifically, practically no
seedlings are grown, but instead orchards are started by planting
fairly large offshoots, which soon strike root, and which often bear
Many valuable seedling dates have been lost in this country because the suckers
were kept closely trimmed off until the trees were in bearing. Only then was their
value discovered after it was too late to propagate them. If an offshoot is always
left attached at the base of the palm it may in turn be allowed to produce suckers
after the parent plant ceases to produce them, and in this way a continuous supply
of offshoots may be produced even at the base of old palms, and no variety need be
lost.
26 THE DATE PALM.
abundantly four or five years after being transplanted (see PL XXII).
However, in the large plantations made in Algeria by the French col-
onists it is not considered advisable to allow the palms grown from
offshoots to bear fruit until five or six years after they are -set out,
and the trees are not in full bearing until eight or ten years after
they are planted. They continue bearing, if well cared for, until they
are a hundred years or more old, a good tree producing an average
of from 60 to 200 pounds of fruit a year," although some trees have
been known to produce as much as 400 or 600 pounds 6 when grown in
rich soil and abundantly irrigated. The tree shown in a previous
paper (Yearbook, 1900, PI. LVII, fig. 1) is a demonstration of the
capabilities of Arizona as a date-producing country. It was only 8
years old from the seed when photographed, and yet bore some 400
pounds of dates. Again, an Amreeyah palm, grown from an offshoot
imported by the Department of Agriculture from Egypt in 1889,
yielded in 1900 over 300 pounds of dates (see Yearbook, 1900, PL
LXII, fig. 1). A little palm growing on the grounds of the University
of Arizona, at Tucson, where the winters are often cold, bore, never-
theless, when it had been transplanted five years, two bunches of fruit
weighing together some 30 pounds (see Yearbook, 1900, PL LVH, fig.
2). The large Deglet Noor palm growing at Biskra, Algeria, shown
in the foreground of Plate LX, Yearbook, 1900, bore over 15 bunches
of fruit, and the young Deglet Noor palm shown in Plate XXII,
grown from a sucker set out only three years before, bore 3 bunches
of fruit.
POLLINATION OF THE DATE PALM.
In a wild state the date palm is undoubtedly pollinated by the wind,
and about one-half of the trees are males. It is probable that pollina-
tion would be incomplete unless the proportion of male trees was
something like one-half, for, although enormous quantities of pollen
are produced, only a very small part of wind-blown pollen ever reaches
the female flowers. The artificial pollination of the date palm was
doubtless discovered by the ancient Ass}^rians, and has been practiced
probably for three or four thousand years at least. Because of the
great economy of pollen brought about by this practice, one male
tree suffices to pollinate from fifty to a hundred females.
The male flower cluster of the date palm consists of a stalk bearing
M. Masselot has published a list of all the important varieties of dates grown in
the Tunisian Sahara (Bui. Direc. Agric. et Comm., Tunis, Vol. 6, No. 19, Apr., 1901),
and gives the average yield per tree of 92 sorts. The Loozee variety has the lowest
average yield, 55 pounds, and the Areshtee and Hamraya the highest, 220 pounds;
the average yield of all the 92 varieties is 116.5 pounds per tree.
ft ln the oasis of Tebbes, the northernmost in Persia, it is reported that a full-grown
tree may yield 200 man (of 3 pounds). Bunge, Petermann's Mittheilungen, 1860,
p. 214.
POLLINATION.
27
a considerable number of short twigs to which the flowers are attached,
the whole contained in a sheath at first entirely closed, but which finally
ruptures, disclosing the flowers. (PI. VII, figs. 1 and 3.) The Arabs
cut the male flower clusters from the trees shortly before the flowers
have fully opened, at a somewhat earlier stage than shown in Plate
VII, fig. 1. The separate twigs to which the male flowers are attached
(PL VII, fig. 3, twig below) are from 4 to 6 inches long, and bear
anywhere from 20 to 50 male flowers, each
containing 6 anthers full of pollen. One of
these twigs suffices to pollinate a whole
female flower cluster, and to bring about the
development of a bunch of dates.
The female flowers, like the male, are borne
inside of sheaths which are at fir^t entirely
closed. Finally the sheath is split open by
the growth of the flowers within (PI. VII,
fig. 2, twig to left), and at this stage pollina-
tion is accomplished. The two tips of the
cracked-open sheath are separated and the
cluster of female flowers pulled out. (PL
VIII, fig. 3.) A twig of male flowers is then
inserted into the cluster of female flowers
and tied in place with a bit of palm leaf or
with a string. (Fig. 2 and PL VIII, fig. 4.)
This completes the operation of pollination.
The fruit cluster soon begins to grow rapidlv,
and in a few weeks the piece of palm fiber
or thread with which the male flowers are held
in place is broken by the pressure of the grow-
ing fruit cluster. Such a fruit cluster, still
confined, but which will shortly break the
fiber, is shown in figure 1 (p. 16).
In the Algerian Sahara the date begins to
flower in April, and sometimes produces
flower clusters as late as June 1. The female
flower clusters, which may be from five to
twenty in number on a single tree, are not all
produced at the same time. It is necessary
in consequence to pollinate each flower clus-
ter as it appears, and sometimes an interval of several weeks elapses
between the appearance of the first and last flower clusters, so the
trees must be ascended several times. The Arabs are very expert in
doing this work and seldom overlook a tree, even where the palms
are planted without any order; indeed, they rarely miss even a single
flower cluster. It requires some skill to climb a tall palm tree, as
FIG. 2. Date flower cluster after
artificial pollination; a sprig of
male flowers has been inserted
among the female flowers and
tied fast with a palm-leaf fiber.
(One-third natural size.) From
negative by the author.
28 THE DATE PALM.
the trunk below is very smooth and it is difficult to pass between the
stalks of the lower leaves in order to get at the flowers, since these
leafstalks are armed with sharp, rigid thorns. (Fig. 1, p. 16.) The
Algerians use no rope or other apparatus to ascend the trees, but
climb up with their bare hands and feet. (PL VIII, figs. 1 and 2, and
PI. XIII.)
When date culture becomes an important industry in the South-
western States it is probable that American ingenuity will devise meth-
ods of simplifying the work of pollination. For example, it would be
easy to find means of marking the trees, and also the flower clusters,
to show which have been pollinated. It might be possible, for instance,
to tie the male flowers in place with a bright-colored strip of cloth,
which would make it easy to see whether all the flower clusters had
been pollinated or not. It is possible that in some places Indians will
be able to take the place of the Arabs and do this work efficiently. , It
is absolute^ necessary to pollinate all the flowers in order to secure
dates of a good quality, although the dates do not fall off. even if the
flowers are not pollinated.
About the end of June, by which time the fruits are of some size,
three fruits will have developed from each flower. Then occurs a
remarkable phenomenon. If the flowers have been pollinated, two of
the three fruits fall, leaving a single date for each flower. If, on the
contrary, the flowers have not been pollinated, all three dates remain
attached and continue to grow, becoming closely crowded together and
somewhat deformed. Such dates are without seeds, but never prop-
erly mature, and are entirely valueless/' This peculiar behavior of the
date palm enables the cultivator to tell by inspection which bunches
have been pollinated and which have escaped attention, and the cutting
away of the excess of bunches from too heavily laden trees should be
postponed until this time, when it is possible to tell which bunches
will mature perfect fruit. As a rule, only one or two clusters should
be left on the young date palms which have just begun to bear, and
only eight or ten even on old trees. Some varieties do not require
much thinning, as they do not produce more bunches than they can
nourish properly, whereas other sorts produce twice as many as the
tree can support.
It sometimes happens that some of the female flowers appear in
spring before any of the male trees have blossomed. To provide a
supply of pollen for such flowers the Arabs make a practice of keep-
ing a few bunches of male flowers from the previous year, which are
placed in tight paper bags and hung up in a cool, dry place. The pol-
len is said to keep without deterioration for at least two years. The
importance of securing male trees which flower at the right time has
been noted on page 24.
Such unpollinated dates have sometimes been supposed by inexperienced observers
to be a superior variety because of their seedlessness.
GATHERING, CURING, AND PACKING DATES. 29
By an inspection of Plate VII, figure 3, it will be easy for those who
possess seedling date palms to determine the sex of the plant as soon
as any flowers are formed. Superfluous male trees can then be
destroyed and replaced by female trees before they have reached a
large size. In case of gardens where there are a few female date
palms and no males available to furnish pollen, it will be necessary to
secure pollen from a distance not a difficult matter, since male flowers
can be shipped anywhere without deterioration if protected against
loss of pollen.
After irrigation the labor of artificial pollination is the most impor-
tant required in a date orchard. The irrigation, however, is very
nearly such as would be given to any fruit trees, whereas the process
of pollination is one that is not required by any other commonly cul-
tivated tree. It should, however, be remembered that for the first
ten or fifteen }^ears after date palms are planted the flowers are so
near to the ground that artificial pollination is performed very easily.
The operation becomes difficult only when the palms are old and verv
tall.
GATHERING, CURING, AND PACKING DATES.
Some varieties of dates require practically no curing, being ready to
pack and ship as soon as they have ripened. Other varieties, however,
require some preparatory treatment. Dates are borne in bunches,
which have a single stem with numerous slender twigs to which the
fruits are attached. (Pis. IX and XXII.) A bunch carries from 10 to
40 pounds. It is very rare that all the dates on a bunch ripen at once,
and in the case of choice varieties those which first ripen are fre-
quently hand picked and shipped at once in order to get the high
prices paid for the earliest shipments. It is also asserted that picking
the outer dates of the bunch, which usually ripen first, permits the
inner fruit to ripen better. Usually the whole bunch is cut off and
hung up in a dry and shady place when most of these dates are ripe
and the remainder beginning to ripen. It has been found necessary
to remove any dates which have begun to spoil before the bunches are
hung up, for if such dates are left the whole bunch may spoil. Usu-
ally within a week or two all of the dates ripen, a and the bunch is
ready for shipment.
The choice varieties of dates are shipped from the Sahara either in
bags or more often in long wooden boxes. They are afterwards
In case the dates do not mature because of an exceptionally cool summer, or in
regions where the summer heat is inadequate, they can be ripened artificially after
being picked by exposing them to the sun during the hot part of the day spread out
on blankets, and storing them indoors at night wrapped up in the blankets on which
they have been exposed during the day. Mr. Hall Hanlon, near Yuma, Ariz. , often
ripens considerable quantities of dates in this manner, which is that followed in
northwestern Mexico (see p. 135).
30 THE BATE PALM.
repacked in smaller boxes, holding from two-thirds of a pound to 10
pounds. (Fig. 5, p. 34, and PL X.) The methods above outlined apply
to the Deglet Noor, which is the variety chiefly exported from Algeria
and Tunis to Europe. Other varieties, such as the Rhars, which are
full of sugary juice when ripe, are not so easily handled. The Arabs
usually hang up the bunches and allow the juice to drain off into jars.
This juice, which they call date honey, is preserved and used, and the
fruit, when it has become somewhat dry, is then packed in boxes or
more often in skins. Dates of this class are usually packed tightly,
and may keep for many years without deteriorating. Somewhat the
same style of packing is practiced at Bassorah and Maskat in Arabia,
whence come most of the dates received in American markets. There
the dates are packed tightly in layers in wooden boxes for export to
America and Europe. The dates containing an abundance of sugary
juice have the disadvantage of being sticky when unpacked, and are
not suitable to serve as a dessert fruit. As before mentioned, the
Deglet Noor does not have this drawback if properly handled. It has,
however, the defect of drying rather rapidly, and from the very fact
that it is not tightly packed in boxes it doubtless dries all the quicker.
With reasonable care, however, it can be kept for some months in a
cool, dry, well-ventilated storeroom, and probabty no other dried fruit
having a value comparable to the Deglet Noor date can be put on the
market with so little labor or at so little risk of loss. Practically the
only hand labor required is that of arranging the dates in layers in
the smaller boxes in which they are sent to the retail trade.
TYPES OF DATES AND VARIETIES SUITABLE FOB CULTURE IN
THE UNITED STATES.
THE THREE TYPES OF DATES.
Of the three principal types of dates cultivated by the Arabs, only
one is exported to Europe and America. This comprises the dates, so
familiar to us, called by the Arabs "soft dates." They contain some-
times as much as 60 per cent of their weight of sugar, and are, in fact,
candied on the tree, being preserved from decay by the enormous
amount of sugar they contain. They contain more or less of a sirupy
juice, which is in some varieties so abundant that it must be allowed
to drain off before they can be packed.
The second type comprises sorts very like those just mentioned, but
having a much lower percentage of sugar not enough to keep them
from fermenting and turning sour. They do not dry readily and are
usually eaten fresh from the tree as a table fruit, being more like
grapes than like ordinary dates. The very early sorts are of this cate-
gory and do not stand shipment to long distances, though they will
prove of great value for home consumption and may be sold on the
TYPES OF DATES. 31
local markets. The Wolf skill date (see fig. 3) from Winters, Cal., is
one of these sorts, as is also the Amaree, the earliest date known in the
western Sahara, which has been recently introduced into Arizona.
The third category embraces what are known to the Arabs as " dry
dates. - ' These are almost entirely unknown to Americans or Europeans,
but are very much esteemed by the Arabs, who consider them to be
better for every day consumption than the soft dates, which latter thev
regard rather as a luxury than a staple food. These dry dates are not
at all inclined to be soft or sticky when ripe, and are frequently so
hard as to be difficult to eat. They are said to drop to the ground as
they ripen, and are gathered by simply picking them up from beneath
the palms as they fall. If stored in a dry place and protected from
weevils, they may be kept for years without deteriorating. Dates of
this type are as yet wholly unknown in our markets, but inasmuch
as they are often of excellent flavor," and are cleaner, keep better, and
are more easily gathered and packed, they can be sold cheaper than
soft dates. It is not unlikely that the best sorts of dry dates may
become favorably known and may be eaten in place of Deglet Noor
dates as a dessert fruit, especially
when the latter sort is out of sea-
son; say, from April to October. .
Mr. O. F. Cook suggests that
dry dates may attain popularity
as a result of the modern ten-
dency toward the use of nuts,
cereal preparations, and other
foods Which do not require COOk- FIG 3 ._w olfskm dates grown at Winters, Cal.
ing, since they would be prefera-
ble to the sweeter soft dates as a regular article of diet, and could be
had at any time of the year in prime condition.
VARIETIES OF DATES SUITABLE FOR CULTURE IN THE UNITED STATES.
When the writer made his last journey to the Sahara in order to
secure offshoots for planting in the Cooperative Date Garden atTempe,
in Arizona, and even when his first report b on the date palm was pub-
A palm which bears dry dates of excellent quality, though of rather small size,
was imported by the Department of Agriculture in 1889, and has fruited for some
years in the Salton Basin in southeastern California at Coachilla. This palm is
probably a seedling and not an offshoot of a named variety as was at first supposed;
it may be called the Coachilla date, and has fruits about H to 1 J inches long and
five-eighths inch wide. They are brownish amber in color, much wrinkled, and
have a dull meal bloom on the surface. The seed is small, light gray in color, blunt,
and with a more or less evident furrow on the back. The flesh, though hard, is
free from fiber and of very good flavor, with a persisting and agreeable aftertaste.
&" The date palm and its culture," Yearbook of the Department of Agriculture,
1900; also reprinted and distributed separately.
32 THE DATE PALM.
lished, it was doubtful whether the best late-ripening sorts of dates
could succeed in any of the arid regions of the Southwest which had
then been irrigated, and consequently particular attention was given
to early-maturing sorts, sure to ripen fully in most parts of Arizona
and California. Many early sorts have been secured by the writer
from the Sahara, among them the Amaree, Tedmama, Areshtee, Hal-
looa, Teddala, Timjooert, .Rhars, Tennessin, and Bent Keballa, and
Mr. D. G. Fairchild has recently secured the Hayani, the earliest sort
grown in lower Egypt. Several medium or early sorts already exist
in California and Arizona among others the Seewah, imported from
Egypt by the Department of Agriculture some thirteen years ago, and
a number of seedlings which have originated in this country, such as
the very early Wolf skill (see fig. 3), the moderately early Lount No.
6, and the Bennet date (see fig. 4), which latter has a remarkably low
proportion (1 to 11) of pit to flesh. With so many early
and medium sorts to choose from, it is probable that
some can be found capable of ripening all along the
northern range of date culture in Texas, New Mexico,
and Arizona, and throughout the interior valley region
of California.
The Rhars, in particular, is a promising variety for
cooler climates, as the fruit ripens very early and is of
good quality, while the plant is very vigorous and easily
propagated by offshoots. Its principal drawback is that
'date,' from Phoe- the fruits are sticky, being so full of sirupy juice that
nix, Ariz. j. ney are (Jif cu it to cure, and must usually be packed
closely in skins or boxes for shipment. It is not improbable, how-
ever, that a good system of curing and packing would get rid of this
sirup and leave the dates in a condition like that of the oriental dates
commonly sold in America.
A large number of the offshoots of the Rhars variety was obtained
in 1900, part being sent to California and part to Arizona.
The Rhars offshoots planted at Tempe in July, 1900, have made a
remarkable showing; nearly 10 per cent of the plants (17 out of 176)
flowered and bore a small crop of fruit only two years after being set
out. ''The Rhars proved to be an exceedingly sweet, tender-skinned
date, maturing in September and October, and can probably be grown
in cooler localities than Salt River Valley." 05 Professor Forbes writes
that, u judging from preliminary experience, the Rhars seems to be a
good commercial date, being very sweet, and drying in ten days to
two weeks time to a firmness permitting of packing and shipping.
Forbes, R, H, Thirteenth Annual Report, Arizona Experiment Station, 1902,
p. 243,
TIIK 1)K<JI,KT NOOK DATK. 33
They seem to be dry enough to pack when they are down to about 85 to
80 per cent of their fresh weight.""
The Teddala is another early sort, having a great advantage over the
Khars in that its fruits can be cured without difficulty. This variety
was brought into notice by M. Yahia ben Kassem. It is a \crv lar^e
date, often 3 inches long, and ripens about the same time as the Khars.
It is as yet but little known, even in North Africa, but is a very
promising sort. The palm is exceedingly vigorous and bears large
crops of fruit. This variety is now growing at Tempe.
It has been noted on page 61 in treating of the heat requirements of
the date that hardy rather than early sorts are needed for southern
Nevada and southwestern Texas, where the summers arc long enough
and hot enough to ripen even late sorts, but where the winters are
sometimes very cold.
Now that considerable areas in the Salton Basin have been put under
irrigation, there is at last open to our enterprising fruit growers a
region superior to most parts of the Sahara for date culture, in which
even the latest and best sorts will ripen perfectly. It now becomes of
great importance to secure these late varieties for trial, as they com-
prise the choicest sorts which bring the highest prices on the American
and European markets.
THE DEGLET NOOK DATE.
Among these late sorts one in particular is worthy of special men-
tion, the famous Deglet Noor.^
This sort is of medium or large size, oval in outline, dark amber
colored, and translucent, with a small, pointed pit. The flesh is linn,
very sweet, and of exquisite flavor and aroma. This date, if properly
handled, remains clean, with the skin smooth, unbroken, and dry, so
that w r hen served as a dessert fruit it has a most appetizing appear-
ance, very unlike the ordinary sticky, misshapen dates from the Per-
sian Gulf region. A bunch of dates showing how the dates are
attached is represented on Plate XXII (see also Yearbook, 1900, PI.
LX), while several dates and a few pits, all natural size, are shown
on Plate IX.
The palm which produces these dates has a slender trunk, bearing
long, narrow leaves, which stand more upright than those of most
other sorts. The bunches of fruit have long, slender stems, which allow
them to hang down when the dates are ripe (PI. XXII). The slender,
upright leaves give this variety a characteristic appearance, which
enables it to be recognized easily even when growing with other sorts.
Forbes, R. H., in letter to the writer, dated Tucson, January 9, 1903.
& In French orthography Deglet Nour; also called Deglet en nour, or Deglat ennour.
13529 No. 5304 3
34
THE DATE PALM.
The fruits undergo no special preparation for the market, but are
simply sorted and packed carefully in boxes suitable for the retail
trade. Such boxes are shown in figure 5 and on Plate X. They contain
from two-thirds of a pound to 11 pounds, and are especially in demand
in Europe for the Christmas markets. The smaller boxes usually reach
the larger markets of this country in January and sell at from 30 to 40
cents each retail, or at the rate of 45 to 60 cents a pound for the dates.
The writer was assured by some* of the largest producers in Algeria
that the supply did not equal the European demand and that large
American orders were refused, while, on the other hand, at one of the
FIG. 5. Deglet Noor dates from the Algerian Sahara, showing methods of packing for retail trade.
largest wholesale and retail groceries at San Francisco it was said that
any quantity could be sold at 35 cents a box (50 cents a pound), if they
could be secured before the holidays. At the same time, selected
Smyrna figs were selling in 1-pound boxes for 30 cents. It is clear
that this date has little in common with the sorts which reach our mar-
kets in bulk from Basso rah, at the head of the Persian Gulf, and from
Maskat, Arabia. If these Deglet Noor dates could be sold for half
what they now bring (which would still be about five to ten times the
wholesale selling price of this sort in the Sahara), the consumption
could be enormously increased in this county, as they would not
TJIK IWJLKT NOOK DATK. 35
compete with the common dates, but would be used as a choice dessert
fruit and for confectionery .
The Deglet Noor is a very late variety, which requires an enormous
amount of heat in order to mature properly. It does not succeed very
well at Biskra, and only in the interior of the Sahara, where the sum-
mer temperatures are higher, is it of the best quality. The finest
Deglet Noor dates are produced in the sunken gardens "ghitan"(fig.
8, p. 69) of the Souf country in the Algerian Sahara (see map, PI. II,
p. 76), where the heat is doubled by reflection of the sun's rays upon
the leaves from the sides and from below, by the sloping sandy sides
of the excavations, in the bottom of which the date palms are planted.
As is shown in considering the heat requirements of the date palm
(pp. 67-69), this sort may not be able to ripen fully in the Salt River
Valle}^, Arizona, but it will surety attain the most complete maturity
in the Salton Basin and will probably ripen earlier there than in the
Sahara, which will allow the dates to be placed on the markets in
ample time for Christmas, while in the warmest situations hand-
picked dates probably can be shipped for Thanksgiving. The cer-
tainty that this choice variety can now be grown in the United States
adds a new interest to date culture, and doubtless many progressive
fruit growers will soon be planting Deglet Noor date palms, the cul-
ture of which gives every promise of being exceedingly profitable (see
p. 136). A full-grown Deglet Noor date palm has been variously esti-
mated to yield from 40 to 60 kilos (88 to 132 pounds) a year on the
average, and certain trees in the sunken gardens of the Souf country
in the Sahara yield as much as 330 pounds of fruit. In the Oued Rirh
country the yield is irregular and a good crop is said to be followed by a
poor one and then by a moderate one, making one good and one medium
crop every three years. It has been found by the French companies
that of the dates yielded by the Deglet Noor palm about one-fourth
are of the first grade, suitable for packing in small wooden boxes (see
fig. 5, p. 34, and PL X), holding from 4 to 11 pounds, about one-
third are second grade and are packed in the two-third pound oval
paper boxes, such as reach our markets, and the remainder, a trifle
over one-third, are third-class dates to be sold in bulk.
Unfortunately the Deglet Noor variety does not produce very many
offshoots and does not grow so rapidly as do most of the less valuable
sorts. In 1900 the writer secured 87 'offshoots of the Deglet Noor,
which were planted at the Cooperative Date Garden at Tempo, Ariz.
(See Pis. XXI and XXII). Of these 47 are now alive and growing
and in a }^ear or two it will be possible to state with certitude whether
this valuable variety will mature in the Salt River Valley. a
One Deglet Noor palm at Tern pe bloomed in 1902, but did not mature its fruit
successfully. (R. H. Forbes, Thirteenth Annual Report, Arizona Experiment Sta-
tion, 1902, page 243. ) Several bloomed in 1903, but still no fruit matured.
36 THE DATE PALM.
It would be desirable to test this sort in the Sal ton Basin, and if pos-
sible some offshoots will be secured by the Department of Agriculture
directly from the Sahara, since it will be some two or three years
before any can be taken from the plants now growing at Tempe."
The Deglet Noor is by no means common in the Sahara, and according
to Masselot b it was carried about two hundred and f orty years ago from
the oasis of Temassin near Tougourt, where it originated, to the oases of
southern Tunis. It had then been known in Temassin only about sixty
years, so the variety is about three centuries old. Masselot gives the
following account of its origin as told by the Arabs: "A revered saint,
Leila Noora, had the habit of making daily ablutions at a point in the
oasis of Temassin called ' Blidet-Amar.' c A seed sprouted fortuitousl} 7
at this point and produced a palm of a new sort of degal (soft date)
which was called degal ennoura or deglat ennour in remembrance of
the saint." Most authorities derive the name from the Arabic noor
" light" and " degal " or " deglet? " soft date," meaning " the date of
the light" or " the transparent date." This is considered by Masselot
as an error, as some other sorts are more transparent; he maintains
that the name means simply " Noora's date."
THE KHALAS DATE.
Mr. Fairchild has also very recently (summer of 1902) secured at
Bahrein offshoots of the famous Khalas, a date from the province of
Lahsa or Hassa in eastern Arabia, near the Persian Gulf. Gurnet/
in his celebrated work on Turkey, refers to it as the most delicious of
known dates.
The celebrated traveler Palgrave mentions this variety as occurring
in the province of Hassa between Hof hoof and Mebarraz in east-central
Arabia, and says : e
Here and for many leagues around grow the dates entitled "Khalas" a word of
which the literal and not inappropriate English translation is "quintessence" a
species peculiar to Hassa, and the facile princeps of its kind. The fruit itself is rather
smaller than the Kassem date, of a rich amber color, verging on ruddiness, and semi-
transparent. It would be absurd to attempt by description to give any idea of a taste,
but I beg my Indian readers at least to believe that a "Massigaum" mango is not
more superior to a "Jungalee" than is the Khalas fruit to that current in the Syrian
or Egyptian marts. In a word, it is the perfection of the date. The tree that bears
it may by a moderately practiced eye be recognized by its stem, more slender than
that of the ordinary palm, its less tufted foliage, and its smoother bark. Its
An experimental date orchard has been established very recently in the Salton
Basin at Mecca (Walters), Cal. Several large Deglet Noor palms have been trans-
planted from Tempe to Mecca and many Deglet Noor offshoots have been ordered
from the Sahara. (See footnote, p. 110. )
& Masselot, F. Les dattiers des oasis du Djerid. in Bulletin de la Direction de
1'Agriculture et du Commerce, Tunis, vol. 6, No. 19, April, 1901, pages 117-118.
cBled et Ahmar near Temacin (Map, PI. II, p. 76).
dCuinet, La Turquie, Vol. Ill, p. 233.
* Palgrave, William Gifford. Narrative of a Year's Journey Through Central and
Eastern Arabia, Vol. I, London, 1865, pp. 172-173.
THE KHALAS DATE, ETC. 37
cultivation is an important item among the rural occupations of Has.a, its harvest
an abundant soimv of wealth, and its exportation, which ivndirs lYmn Mosmil on
the northwest to .Bombay on the southeast, nay, I believe to the African coast of
Zan/ibar, forms a large branch of the local commerce.^
Mr. Fairchild says Europeans and Arabs in that region agree in
considering it to be the best date in the world. He further says:
I do not hesitate to pronounce it second or third only to the Deglet Noor, which it
even surpasses in date flavor. I have always thought the Deglet Noor a most deli-
cate date, but lacking in that indescribable date flavor which characterizes these
Persian and Arabian sorts. The Khalas is a sticky date, but of most unusual flavor.''
In his report on the "Persian Gulf Dates" Mr. Fairchild says:
The skin is a golden brown and of most delicate texture, covering closely the
rich golden flesh, which is of exquisite date flavor and with the consistency of
a chocolate caramel. c
OTHER PROMISING DATES.
Among numerous other sorts secured by the writer from various
regions in the Algerian Sahara and now growing in the Cooperative
Date Garden at Tempe, Ariz., the following are especially noted for
their superior quality, all being considered by some to equal or to be
superior to the Deglet Noor in flavor.
(1) The Teddala, a very large, very early sort from M'Zab in west-
ern Algeria (see page 33).
(2) The Iteema, a midseason date, short and round, with soft flesh,
very sweet, said to keep well; in Tunis it is very much esteemed and
is considered suitable for export.
(3) The Bent Keballa, possibly a large form of the Iteema, consid-
ered one of the best varieties in M'Zab.
(4) The Timjooert, also from M'Zab, a medium-sized red date, so
full of juice that the fruit drips honey from the tree when ripe; when
properly cured keeps well and is of most excellent quality; flesh gran-
ular with almost no fibers about the seed; very sweet.
(5) The Ham ray a, a very large, dark-red date, ripening very late;
flesh free from fiber arid of good flavor; in Tunis it is the largest date.
known and one of the two heaviest bearers/ the average yield being
220 pounds per tree.
(6) The Mozaty or Mazauty date, from the Pangh Ghur country e in
Baluchistan, recently secured by Messrs. Lathrop and Fairchild, has
been highly extolled. It is said by Fischer, in his monograph of the
Mr. D. G. Fairchild reports that Khalas is a delicate packer and is nowadays
never exported except in form of presents. (See Bui. 54, Bureau of Plant Industry,
U. S. Department of Agriculture, 1903, p. 25.)
& Fairchild, D. G. In letter dated Bassorah, February 22, 1902.
c Fairchild, D. G. Persian Gulf Dates and Their Introduction into America. Bui.
54, Bureau of Plant Industry, U. S. Department of Agriculture, p. 25.
^The Areshtee is the other. (See page 26, footnote a.)
^Some thirteen days' caravan journey from the port of Gwadur, on the Gulf
of Oman.
38 THE DATE PALM.
date palm, to be "the best date in the celebrated date region Pandsch-
gar." a This variety is reported by Mr. Fairchild to be one of the
finest in the world; it "is packed in date syrup in small jars and sold as
a great delicacy in the Kurrachee market." Such preserved Mozaty
dates were eaten by Mr. Fairchild in February, 1902, at Kurrachee.
He says, "They impressed me as the richest flavored dates I had ever
tasted." 6
THE ORDINARY DATES OF COMMERCE.
The standard varieties of dates which are grown along the Shat-cl-
Arab River and which are exported from Bassorah to America and
Europe in enormous quantities have recently been secured and intro-
duced into this country by Messrs. Lathrop and Fairchild. The prin-
cipal varieties grown for export in this region are the Halavvi,
Khadrawi, and the Sayer. Of these the Halawi is doubtless the best;
it is a medium-sized, rather light-colored, sticky date, and forms the
best grade of the ordinary dates imported into America. The tree
grows well on an adobe soil and needs much water. From the region
about Maskat Messrs. Lathrop and Fairchild secured the Fard date, of
which about 1,000 tons a yeW are exported. It is largel} 7 shipped to
America, but it is darker colored and inferior in flavor to the Halawi
of Bassorah, according to Mr. Fairchild/ whose recent bulletin should
be consulted for a detailed account of the varieties and methods of
culture observed by him in a trip through the oriental date regions.
VARIETIES OF DATES THAT SHOULD BE SECURED FOR TRIAL IX THE UNITED STATES.
There are other very promising late sorts which should be secured
as soon as possible, even at considerable expense, in order that the} 7
may be tested in the Salton Basin and in Arizona in comparison with
the Deglet Noor.
Among these may be mentioned the Menakher (or Monakhir) of the
Tunisian Sahara, a variety later than the Deglet Noor, with large
brown fruits which attain the length of tha little finger. This sort is
rare and much sought after in the Tunisian Sahara, where it sells for
slightly more than the Deglet Noor, which it surpasses in length by
50 per cent and to which it is by many considered superior in quality.
The average yield of a Menakher palm is said to be 30 kilos or 66
pounds, only half the yield of the Deglet Noor. The offshoots are
more costly than those of the Deglet Noor, selling at from 4 to 6 francs
each, while those of the Deglet Noor cost only 2 to 3 francs, and the
ordinary sorts from 1 to 3 francs.
Fischer, Th. Dattelpalme, p. 26.
6 Fairchild, D. G. Persian Gulf Dates and Their Introduction into America.
Bui. 54, Bureau of Plant Industry, U. S. Department of Agriculture, 1903, p. 27.
Fairchild, D. G. Persian Gulf Dates and Their Introduction into America.
Bui. 54, Bureau of Plant Industry, U. S. Department of Agriculture, 1903, p. 25.
VARIETIES THAT SHOULD BE TESTED. 39
Another sort of great promise is the Wahi, of which samples were
secured by Mr. Fairchild in the market of Fayoum, in "west-central
Egypt. This variety is said to come from the oasis of Seewah, known
to the ancients as Ammon, or Ammonium, some 300 miles to the west-
ward, in the interior of the Sahara Desert. The date is brown, less
transparent than the Deglet Noor, but rather longer and decidedly
broader; the seed is blunter and much more irregular in outline. The
flesh is yellowish, granular midway between the skin and the seed, and
of a most delicious llavor. This date had been gathered and kept,
with no precautions against drying out, for at least eight months \vlirn
it was received at Washington, but it was still in very good condition,
except for the attacks of weevils. It seems to be a better keeper and
to have a higher flavor than the Deglet Noor. Nothing is known as
to the palm which produces this date, but from the quality of the
fruit it is presumably a late-maturing variety.
Dates of a superlatively good quality are reported from Morocco,
and Mr. O. F. Cook a obtained some years ago at Tangiers, from a
European official in the emplo3 r of the Sultan, dates which he considers
superior to the Deglet Noor. These dates were about as long as
and somewhat thicker than the Deglet Noor, but more wrinkled and
of a darker color. They were covered with a bloom and were so dry
that the flesh was firm and not at all sticky. At London a prominent
produce dealer in Covent Garden market assured the writer that the
Tafilet dates were better than the Deglet Noors, which are also much
appreciated in England. Inasmuch as the drier grades of Deglet Noor
dates are preferred in England, it may be that the Tafilet dates of the
London markets are the same as the dry variety Mr. Cook secured at
Tangiers. No good dates are produced west of the Atlas Mountains in
Morocco, and any sort of superior quality must come from the Moroc-
can Sahara, very probably from Tafilet, the largest and most impor-
tant Moroccan oasis, though Mdaghra and Tissini are also reported to
produce excellent dates. Rohlfs, 6 the celebrated African explorer,
says: " The dates of Tafilet are known as the best in the whole desert;
the varieties Buskri, Bu Hafs, and Fukus are most sought and bring
the highest price."
The importance of securing a date possibly superior to the Deglet
Noor would warrant sending Arab or Berber merchants to these oases
to investigate the quality of the dates and to secure offshoots of the
better sorts. In the present unsettled state of trans- Atlasian Morocco
it would be hazardous for Americans or Europeans to venture there.
The Mirhage date of Mandalay, some three days' journey from Bag-
dad, and the very similar but somewhat inferior Maktum of Bagdad,
Oral communication to the writer, 1900.
& Rohlfs, Gerhard. Tagebuch seiner Reise (lurch Morocco nach Tuat. In Peter-
mann's Geographische Mittheilungen, 1865, Heft 5, p. 175.
40 THE DATE PALM.
are considered by Mr. Fairchild as being very promising sorts. The
Maktum is u a soft, sticky date with a small stone, no fiber, and a
beautiful golden-brown skin which adheres closely to the golden,
brownish-yellow flesh. " a It matures in August. Unfortunately the
Mirhage could not be secured by Mr. Fairchild at the time of his visit
to Bagdad in 1902, though he sent the Maktum to this countiy, where
it is now growing.
The dates of Bafk and Terachabad, in Persia; of Medina 6 and Tur, c
in western Arabia; of Kasem, in central Arabia; of Nedjed, in eastern
Arabia; of Say and Sukkot/ 7 in Nubia; of Dakhel, in western Egypt;
of Traghen, in Fezzan; and of Tafilet, Mdaghra, andTissini, in eastern
Morocco, have been lauded by experienced travelers, and if possible
these oases should be visited and offshoots secured of the best sorts,
since it is now possible to bring even the latest varieties to full maturity
by planting in the Salton Basin. Heretofore the uncertainty as to the
possibility of growing the best late sorts has discouraged any attempt
to obtain the varieties from the more remote regions; but now, when
date culture is still in its infancy, is just the time when these sorts
should be secured and tested, in order that no mistakes be made and so
that only the best sorts be planted out. Once planted, a date palm can
not be changed to another variety, as can all other ordinary fruit trees,
for palms can not be grafted or budded. To change the variety it is
necessary to dig up the old trees and plant young offshoots of the sort
desired; in other words, to destroy the old orchard and plant a new one.
In view of the fact that offshoots are now very expensive, and that
it costs more to plant an acre to date palms than to any other fruit tree,
and in view of the fact that date palms can be propagated only at a
slow rate by removing one or two offshoots annually and can not be
increased indefinitely by budding or grafting, as with other trees, it
becomes very important to secure a collection of the best sorts of date
palms as soon as possible, in order that all the best varieties may be
Fairchild, D. G. Persian Gulf Dates and Their Introduction into America.
Bui. 54, Bureau of Plant Industry, U. S. Department of Agriculture, 1903, p. 23.
& "The best kind [of Medina dates] is Al Shelebi; it is packed in skins or in flat,
round boxes, covered with paper, somewhat in the manner of French prunes, and
sent as presents to the remotest parts of the Moslem world. The fruit is about 2
, inches long, with a small stone, and is seldom eaten by the citizens, on account of
the price, which varies from 2 to 10 piasters [about 9 to 43 cents] the pound. The
tree, moreover, is rare, and is said not to be so productive as the other species."
(Burton, Narrative of a Pilgrimage to Mecca, vol. 1, pp. 400-401.)
c "The small, yellow dates of Tur * * * are delicious, melting like honey in
the mouth, and leaving a surpassing arrtire gotit." (Burton, Narrative of a Pilgrimage
to Mecca, vol. 1. p. 204.)
d '"In Nubia the dates of Ibrim are celebrated, but still more so those of Sukkot
and Say, the sweet aromatic Sultani, which attain a length of 3 inches." (Fischer,
Die Dattelpalme, p. 25. )
INTRODUCTION OF SAHARAN YAKIKTIKS. 41
compared and that there may ho time to secure a supply of offshoots
before the "rush" lupins and whole regions are planted to date-.
Fortunately it will doubtless be possible to secure the Khars for the
cooler arid regions and the Deglet Noor for the hottest deserts in anv
desired numbers when once the demand for the offshoots exisN.
INTRODUCTION OF SAHAKAN VARIETIES OF DATE PALMS INTO THE
UNITED STATES.
Seedling dates have long been growing in California and Arizona,
and still longer in Mexico, but only recently have successful importa-
tions been made of offshoots of date palms, by which alone the varie-
ties can be propagated. In 1889 the Division of Pomology of the
Department of Agriculture imported some 59 offshoots from Egypt,
9 from Algeria, and 6 from Maskat, and, although many were lost,
those sent to the Arizona Experiment Garden in Phoenix, in the Salt
River Valley, grew well and fruited at an early age. (See Yearbook,
1900, PL LXII, fig. 1.) It was, however, found that most of the off-
shoots from Eg} f pt had been falsely named; many bearing the names
of valued sorts proved to be ordinary males of no value. Some few
female palms bearing fruit of fair quality were included in the ship
ment, however, and the success of these proved the Arizona climate
and soil to be suited to the culture of at least the Egyptian sorts.
Prof. James W. Tourney first directed attention to the success of the
date palm in central Arizona, as evidenced by the production of an
abundance of f ully matured dates, both by the seedlings planted by
American settlers and by offshoots imported by the Department of
Agriculture/' It was the success of these early importations which
rendered it desirable and feasible to undertake the recent large impor-
tations of offshoots made in 1899-1900.
Shortly after the organization of the Section of Seed and Plant Intro-
duction in the Department of Agriculture in July, 1898, attention was
directed to the desirability of securing a large assortment of correctly
named offshoots, particularly from the Algerian Sahara, whence are
exported the best dates which reach Europe and America. The Uni-
versity of Arizona and the Arizona Agricultural Experiment Station
meanwhile offered to provide a special date garden, and to set out,
irrigate, and cultivate the palms, if the Department of Agriculture
would furnish a collection of offshoots of the best sorts of dates grown
in the Old World. This offer was accepted, and in the winter and
early spring of 1899 the writer visited, under instructions from the
Secretary of Agriculture, the oases in the Sahara Desert about Biskra,
Algeria. A few offshoots were secured and forwarded as a trial
Toumey, J. W. The Date Palm. Bui. No. 29, Arizona KxprriiiH-nt Station,
Tucson, Ariz., June, 1898, pp. 50, figs. 13.
42
THE DATE PALM.
shipment, and a large number was contracted for, to be delivered the
following spring.
In May and June, 1900, the writer again went to Algeria for the
purpose of shipping to Arizona the date offshoots previously con-
tracted for and to purchase such additional offshoots of good sorts as
could be had. As a result of this second visit 440 offshoots, consisting
of some 27 varieties, were obtained and shipped (see PI. VI) to the
Cooperative Date Garden at Tempe, Ariz., where 381 of the offshoots
were planted (see fig. 6 and Pis. XXI and XXII). Of the remainder
21 were sent to Phoenix, Ariz., and 35 to the date gardens at the sub-
stations of the California Experiment Station at Pomona and Tulare
and to private growers in California.
PIG. 6. Cooperative Date Garden at Tempe, Ariz. The offshoots imported from the Algerian Sahara
in 1900 have just been set out and a workman is planting one in the foreground. From negative by
Prof. R. H. Forbes, August, 1900.
This shipment, which was the largest that ever left North Africa,
came through in two months and arrived in good order. An innova-
tion was made in packing the offshoots. It had been the custom to send
them rooted in tubs, entailing the great expense of a year or two of
care in a nursery to get the plants properly rooted, and then heavy
freight charges on account of the bulk and perishable nature of the
plants. The writer shipped the offshoots packed simply in boxes
with damp moss about the bases, a in charcoal, or in straw, with no
moisture whatever (see p. 21). A late report of Prof. R. H. Forbes,
director of the Arizona Experiment Station, who gave his close
a For fuller details see the writer's report, " The date palm and its culture," in
Yearbook, Department of Agriculture, 1900.
INTRODUCTION OF SAHARAN VARIETIES. 43
personal attention to the planting and subsequent care of these ofVsho< >t>.
shows that of the entire 38 plants set out in the Cooierativr Date
Garden at Tempo and at Phoenix, 294 were living, while !o wnv dead. '
These figures show that over 75 per cent of the offshoots have become
established. (See Pis. XXI and XXII.) More than so per cent of
those sent directly from the Sahara by the new system of packing-
lived, but the average was reduced by the plants that had been grown
in tubs a year before shipment, of which only about ;>s per cent lived.
The offshoots simply packed in straw came through as well as those
carefully wrapped about the base with moist moss or packed in char-
coal. Inasmuch as only 70 to 75 per cent of the offshoots are expected
to live in the Sahara when they are planted in the open without pro-
tection, as was done at Tempe, 6 the remarkable record was made of
securing the growth of more offshoots in Arizona after a two months'
voyage than would be expected to live in the Sahara, and that, too,
even with the most inexpensive method of shipment that could be
imagined that of simply packing the suckers closely together in dry
straw in ordinary wooden cases.
This experiment has demonstrated the possibility of importing date
offshoots from the Sahara and placing them in the deserts of the South-
west in practically as good condition as when they were cut off the
parent tree. The importance of this experiment is obvious, for it
renders it certain that offshoots can be transported to great distances
without loss, and makes it possible to undertake the culture of dates
on a commercial scale by importing offshoots for planting. Doubtless
means will be found to supply the demand for offshoots as soon as it
arises b} r importation from the Sahara. In the meantime many of
the best sorts of southern Algeria are on trial at Tempe, Ariz., and
doubtless some will be found adapted to the climatic conditions there.
As was previously noted in the paragraph on varieties, it is greatly
to be desired that the Deglet Noor and other late sorts be set out as
soon as possible in the Salton Basin, in order that there may be a prac-
tical demonstration of the suitability of this region for the culture of
the choicest sorts of dates.
THE DATE PALM AS A SHELTER FOB OTHER FRUIT TREES.
In many parts of the northern Sahara the date palm is almost as
important as a shelter and partial shade for other fruit trees as it is for
its own fruit. At the time of the Roman occupation of Africa these
oases were largely planted to olive trees, some of which, indeed, still
remain giant stems perhaps 1,500 years old. It happens that the
Forbes, K. H. Thirteenth Annual Report, Arizona Experiment Station, 1902,
p. 242.
&Marcassin. L' agriculture dans le Sahara de Constantine. In Annalee de 1'Inst
Agronomique, 1895, p. 62 of reprint.
44 THE DATE PALM.
olive is about the only other fruit tree which is able to stand without
injury the fierce heat, intense light, and the driving sand storms of
the Sahara, and even the olive itself grows better and yields more
fruit if planted under the protecting shelter of the date palm. Most
other fruit trees, such as the apricot, peach, almond, pomegranate, fig,
and jujube, can be grown successfully in the Sahara only in the shade
of other trees, and do best where grown under the date palm. In the
northernmost oases of the Sahara the dates are frequently of inferior
quality, whereas the other fruit trees do better here than in the hotter
and drier regions farther south. Many of these northern oases have
veritable orchards growing under the half shade furnished by the
crown of slender leaves of the date palms far above. This is well
shown in Plate XII, which represents a fig orchard growing under date
palms at Chetma, Algeria. It sometimes happens that vegetables are
grown under the fruit trees, in which case it is possible to see three
crops occupying the soil first, the date palm, towering far above;
then the fruit trees, and under them the more delicate and shade-loving
garden vegetables. It is not at all impossible that in some parts of our
own Southwest the date palm may prove very useful in the manner
above described, serving as a shelter and partial shade to more delicate
fruit trees which thrive perfectly in regions where the summers are
far too cool to allow of the culture of the best sorts of dates.
IRRIGATION OF THE DATE PALM.
AMOUNT OF WATER NECESSARY FOR A DATE PALM.
The date palm requires a continuous supply of moisture about the
roots and can not maintain itself in as dry a soil as can some desert
plants. Much experience has been accumulated by the French planters
in the Algerian Sahara as to the amount of water necessaiy to enable
a date palm to grow and fruit well. M. Jus, the celebrated civil engi-
neer, who has done so much to reclaim the northern Sahara by a study
of its artesian water supply, considers a that each palm tree requires
one-third of a liter (0.35 quart) per minute at the flowing well or main
irrigating canal, and palms which receive from 0.4 to 0.5 of a liter
(0.42 to 0.53 quart) per minute are more vigorous and yield more fruit
even if crops are grown underneath. If each tree receives 0.35 quart
per minute this would amount to 126 gallons per day, or about 17
cubic feet. At 1 pint per minute the daily consumption would be 180
gallons, or a little more than 24 cubic feet. These data are not for
the amount of water actually furnished the trees, but for the amount
which must be allowed for each tree at the head of the principal irri-
gating canals. Of course some of the water is lost by evaporation
and seepage before it reaches the palms.
a Jus, H. Les oasis de POued Rir', Paris (Challamel), 1884.
AMOUNT OF WATER NECESSARY. 45
M. Holland, Avho has written a very complete account of the water
supply of the Algerian Sahara," and who is himself one of the mem-
bers of a firm which has created extensive date plantations in the Oued
Rirh country, in the Algerian Sahara, considers that one-half liter
(0.53 quart) per minute should be allowed to each palm to secure, the
best results.
M. le commandant Rose, himself an experienced planter, has pub-
lished a most detailed statement 6 regarding the practice of irriga-
tion in the Oued Rirh country, where the water supply is furnished
by artesian wells. He recommends 24 irrigations of 3 cubic meters
(7i>2.r> gallons) each, making 72 cubic meters, or 19,021 gallons during
the year. During the hot season, from June to September, inclusive,
weekly irrigations are practiced, 17 in all, consuming 51 cubic meters,
or 13,473 gallons per tree, which is at the rate of about 113 gallons
per day, or about 0.314 quart (0.3 liter) per minute, the lowest of the
three estimates. During the autumn and winter 2 irrigations, and
during spring 5 irrigations, are prescribed.
When the supply of water is invariable, as for example the flow
from an artesian well, it is necessary to plant only the number of
palms that can be properly irrigated by the available water supply
during the hot season, when the amount needed is greatest. Where
irrigation is practiced by means of water conducted from rivers or
from storage reservoirs in canals, as is the case in most of the arid
regions of the Southwest, it will be even more necessary to determine
carefully how much water can be had in summer to avoid planting
more dates than can be properly irrigated.
In the plantations made recently by French proprietors in the Alge-
rian Sahara, the date palms are usually set out 8 meters, or 26 feet,
apart, making 143 to the hectare, or 60 to the acre. Some of the
planters consider this distance too small and plant about 10 meters (33
feet) apart, making about 40 to the acre, while others, among them the
celebrated civil engineer Rolland, consider 200 to the hectare, or about
80 to the acre, as being the best number to plant.
Taking 60 to the acre, 26f feet apart, as a good number to plant, the
amount of water needed per acre can easily be calculated. Using
Rose's estimate of 19,021 gallons per tree per annum, 3 acre-feet of
water would be required, of which 2-f acre-feet would be used during
the four summer months from June to September, inclusive. Using
Jus's estimate, which puts the least amount necessary at one-third
Rolland, Georges. Hydrologie du Sahara algerien (chemin de fer transsaharien ) ,
Paris, Imprimerie Rationale, 1894, p. 9.
& "La culture du dattier dans le sud constantinois, par un homme du sud." Alger.
1898, Pierre Fontana & Cie, Paris, Augustin Challamel. 8. 20 pp. The identity
of the author of this pamphlet was disclosed by Eolland (Hydrologie du Sahara
algerien, p. 167).
46 THE DATE PALM.
liter (0.35 quart) per minute, or 126 gallons per day, a trifle over 4
acre-feet would be required, of which nearly 3 acre-feet would be used
in the four hottest months, from June to September, inclusive. On
the basis of Holland's estimate, which is also given by Jus as the
optimum quantity, viz, one-half liter (0.53 quart) per minute, or 190
gallons per da}-, some 5i acre-feet a year would be required, of which
4 acre-feet would be used during the four summer months, or at the
rate of 16 acre-feet per annum.
The amount of water needed per acre depends of course directly on
the number of date palms per acre, and in planting care should be
taken not to set out more than can be irrigated with the water supply
covering the land.
It must be remembered that the figures given above are for the
western Sahara, a region noted for its extreme dryness, where the
evaporation from a free surface of water often averages nearly one-
half inch per day during the three summer months June, July, and
August. It is probable that a smaller amount of water would suffice
in regions where the air is not so dry and consequently where the
evaporation is less, as, for example, in the Salt River Valley and most
other parts of southern Arizona/ while in hotter, drier regions, such
as the Sal ton Basin, even more will be required. In the latter region
it will be well to allow only about 12 palms to each acre-foot of water
available, and this only if the water can be had whenever desired during
the summer. This would permit planting some 50 date palms to the
acre where 4 acre-feet of water are available whenever needed during
the year.
It must be remembered in considering the needs of the date palm
that the water supply must be practically continuous; that is to sa}^
that the ground must in some way be kept damp throughout the entire
year. It is probable, however, that the date palm does not require as
much water as do ordinary fruit trees. It is, indeed, probable that
owing to their having thick, leathery leaves, protected by a coating
of wax, they evaporate a considerably less quantity than would an ordi-
nary fruit tree having delicate leaves not adapted to withstand the hot,
dry air of deserts. It is nevertheless necessary for the roots to have
o At Tucson, Ariz., the average of three years' records taken at the University gives
the annual evaporation from a free surface of water at 77.7 inches, and the average
rate during the three hottest months, June, July, and August, at one-third inch per
day. At Tempe, in the Salt River Valley, Arizona, a calculation by the United States
Geological Survey from imperfect data gives 91 inches as the probable annual evapo-
ration. At Biskra the careful records of M. Colombo show a mean annual evapora-
tion during the ten years from 1884 to 1893 of 2.8374 meters, or 111.7 inches, averaging
12.47 mm., or 0.4915 inch (very nearly one-half inch) per day during June, July, and
August. In the Oued Rirh country, where most of the observations relative to the
amount of water necessary for irrigating date palms have been made, the rainfall is
less than at Biskra and the temperature higher, so the evaporation is doubtless greater.
AMOUNT OF WATER NECESSARY. 47
access to moist earth throughout the entire year, since, as has hern
stated above, the date palm is not at all a desert plant, in the sense of
being able to exist on very dry soil, and would die in many <>f the situ-
tions in the Southwest where cacti and yuccas thrive.
Where the supply of irrigation water is limited, as at IViskra. where
there is only 0.12 liter per minute available for each palm and where
the soil is very heavy and consequently difficult to saturate, irrigation
is commonly practiced by filling up with water a cavity "dahir"
excavated at the base of the tree (PL XVII, fig. 2, and Yearbook, 1000,
PI. LV, fig. 3). Where water is more abundant and especially where
crops are grown under the palms it is customary to flood the whole
surface of the ground, the land being divided into small beds from 10
to 30 feet in diameter, which are surrounded by a slightly raised rim
(PI. XVII, fig. 1). When irrigated the whole bed is flooded, the water
being retained by the surrounding ridge. A larger amount of water
is required when applied in this manner than would be necessary if
poured into a trench at the side of the palm, but the alkali is washed
into the subsoil by surface flooding, whereas it is brought to the sur-
face by the trench system, which should never be followed in danger-
ously alkaline soils. In the Salton Basin in particular, where the
subsoil is often heavily charged with alkali, the land should always be
watered by flooding or else by deep furrows, even where the surface
soil does not contain harmful quantities of alkali."
Where there is water at a short distance from the surface within
reach of the roots, as is the case in the area about the Cooperative Date
Garden at Tempe, Ariz, (see Pis. XXI and XXII), at Farfar, Algeria,
in the western Zab, between Fougala and Biskra, Algeria (PI. XIV,
fig. 1, and Yearbook, 1900, PL LIX, fig. 7), and in the Souf country
in the Sahara (fig. 8, p. 69) the amount of water required for irriga-
tion is less when once the palms have become established. They can
even exist without any irrigation whatever from the surface, although
in this event they do not grow as well and bear very much less fruit,
probably because of imperfect aeration of the soil about the roots and
because of the continual rise of alkali from the subsoil, as will be
explained in the chapter on drainage.
Well aerated running water is desirable for date palms and water-
logging of the soil must be prevented. If these conditions are fulfilled
this plant can live and thrive when irrigated with water so salty a> to
kill all ordinary plants, as will be shown later in treating of the alkali
resistance of the date palm.
Snow, Hilgard, and Shaw (in Bui. 140, Cal. Exp. Sta., pp. 36-39) recommend
for the Salton Basin first washing the alkali down by surface flooding and then pre-
venting its subsequent rise by deep-furrow irrigation. However, the date palm is
not sensitive to surface accumulation of alkali when once established, as will l>c
shown farther on (see p. 117).
48 THE DATE PALM.
Irrigation by menus of flooding is sometimes practiced in Egypt for
the date palm, as has been done for all sorts of crops since remote
antiquity. The water covers the land to a depth ranging from a few
inches to several feet (see PI. XI), and remains on the soil for about
six weeks. a This method of irrigation is riot likely to prove desirable
anywhere in this country unless it be in the flood-plain of the Colorado
River in California and Arizona (see p. 131). It may be desirable to
use this method of flooding in order to wash the alkali out of the sur-
face layer of the soil where the accumulation of alkali in the upper
layers of the soil is so great as to prevent the best growth of the date
palm. It is of interest in this connection to note that the Egyptian
date palms are able to endure having their roots submerged for long
periods without appreciable in j ury .
Mr. D. G. Fairchild has described a very interesting system of com-
bined irrigation and drainage practiced in the date plantations along
the Shat-el-Arab River at the head of the Persian Gulf, which are
doubtless the most extensive in the world. The level valley land
along the river is cut up into small rectangles, 10 to 15 by 20 to 30 feet
on a side, by irrigation ditches, through which, twice a day, water
flows when the river is backed up by the tide. As the tide recedes
the water flows out of the ditches, preventing stagnation and caus-
ing a lowering of the water level in the soil. The soil is doubtless
thoroughly aerated by this alternate rise and fall of the level of the
ground water. By this interesting system of tidal irrigation, which,
without any trouble beyond the first labor of digging the ditches pro-
vides for very perfect watering, drainage, and aeration of the soil, date
palms thrive in this region where the soil is as pure an adobe as the
clay of a brickyard. 6
Such a system of combined irrigation and drainage can, of course, be
applied only where a river is backed up by high tides. No such con-
ditions occur, or at least not on any considerable scale, within the date
regions of the United States, since the region along the Sacramento
River in California where tidal irrigation can be practiced is so cooled
in summer by the cold winds and fogs from the Pacific that none but
the very earliest sorts of dates could mature. Along the Colorado
River, near its mouth in Mexico, it is possible that tidal irrigation
could be used in date culture, since the tides in the Gulf of California
are very high and the climate and soil in this region are favorable to
the culture of early and midseason dates/
a Kearney, Thos. H., and Means, Thos. H. Crops used in the reclamation of
alkali lands in Egypt, Yearbook, Department of Agriculture, 1902, p. 504.
& Fairchild, D. G. Persian Gulf Dates and Their Introduction into America. Bui.
No. 54, Bureau of Plant Industry, U. S. Department of Agriculture, 1903, p. 14.
c However, the head of tide water is only about fifteen miles above the mouth of
the river (as may be seen on fig. 10, p. 102), and consequently there is not room for
such immense date plantations as those described by Fairchild around Bassorah.
WARM IRRIGATION WATER ADVANTAGEOUS. 49
In many parts of California and possibly in some parts of Arizona
there is enough rainfall to support the date palm without irrigation
(see p. 124). The Wolfskill date palm at Winters, Cal., for example,
is never irrigated, yet bears abundant crops of good dates every year.
In regions where the winters are very cold it is unwise to irrigate
late in summer, except when necessary to keep the palms alive, since
abundant watering forces a tender new growth, which is likely to be
killed by the freezes of the succeeding winter. At Tulare, in the San
Joaquin Valley, California, where there are from 6 to 34 severe frosts
every winter and where the temperature sometimes falls as low as
17 F. or lower, the gardeners of the substation of the Agricultural
Experiment Station consider it unwise to irrigate date palms after the
month of June.
WARM IRRIGATION WATER ADVANTAGEOUS.
The growth of the date palm and the maturing of its fruit are
hastened by supplying warm water to the roots. For example, in
the oasis of Chetma, Algeria (see PL XII and Yearbook, 1900, PL
LIX, fig. 8), largely supplied with water from warm springs having
a temperature of 94.1 F. (34.5 C.), the Deglet Noor date ripens
early in the season, especially on those trees growing near the
springs and which, consequently, receive warm water even in winter
and early spring, when the air is still cold. Biskra, near by and at
nearly the same level, though less protected against cold winds, is
also irrigated largely from springs, but the temperature of the water
of these springs is only 70 to 81 F. (21.5 to 27.33 C.), and the
water is cooled in winter and spring by admixture with the run-off
from the Atlas Mountains to the north and by flowing a couple of
miles in open canals before it reaches the nearest date palms. Here
the Deglet Noor date does not mature so well as at Chetma and is not
of the best quality. The artesian wells of the Oued Rirh country (see
map, PL II, p. 76) furnish water of a temperature ranging from 76.3
to 79 F. (24.6 to 26.1 C.), and in the Souf country the ground water
to which the palms send down their roots is much colder, having a
temperature of only 57.2 to 68 F. (14 to 20 C.); but in these regions
the summer heat is much greater than at Biskra and usually suffices to
enable the Deglet Noor to mature perfectly.
In the Salt River Valley, Arizona, the irrigation water is conveyed
in open canals mostly shaded by cottonwood trees. The temperature
of the water naturally varies with the season. In June, when the tem-
perature of the air ranged from 82 to 104 F., Professor McClatchie
found the temperature to range from 73 to 94 F. in the canals and
from 82 to 88 F. in the smaller irrigating ditches. It should be
noted that in June the supply of irrigating water is less than for any
other month of the year, and probably in February, March, and April,
13529 No. 5304 4
50 THE DATE PALM.
when the canals are full of the water from melting 1 snows on the sur-
rounding mountains, the temperature would be much lower.
The Salton Basin is supplied with water diverted from the Colorado
River near Yuma and conducted some 40 to 60 miles in open ditches
before it is put on the land. The annual overflow of the Colorado
River occurs in early summer, usually in June or July, and is caused
by the melting of the snows on the Rocky Mountains in Colorado,
Utah, and Wyoming. This cold water fortunately reaches the Colo-
rado Desert at a time when the heat is great, so that in flowing in the
large open canals and in the shallow laterals and in soaking through
the hot surface layers of the' soil it will undoubtedly be warmed con-
siderably before it reaches the roots of the date palms. On the whole
the conditions are exceptionally good in the Salton Basin, for the most
abundant supply of water occurs in early summer or midsummer, just
when the plants have greatest need for it.
The annual overflow of cold waters from the melting snows is doubt-
less the principal cause of the failure of the date palms to mature their
fruit properly on Mr. Hall Hanlon's place in the Colorado River flood
plain in California, near Yuma, Ariz, (see PI. XX, fig. 2). The tempera-
ture of the soil and of the air in this overflowed area and in adjoining
areas at nearly the same level is doubtless much lower than at the
town of Yuma, for instance." Even at Yuma the summer heat is less
than at Phoenix and very much ICGG than in the Salton Basin. It is
clear then that no conclusion unfavorable to the culture of dates in the
Salton Basin can be drawn from the failure of these palms in the flood
plain to mature their fruit. Early varieties, such as the Rhars and
Teddala, will probably ripen even on these overflowed lands (see p. 132).
DRAINAGE FOB THE DATE PALM.
Although the date palm can withstand very much more alkali than
any other crop plant, it does not endure having the soil about the roots
water-soaked. Good drainage is as essential for it as for any other
fruit tree if good crops are to be expected, and, unless the soil drains
naturally, the superfluous water must be removed, usually -by means of
open ditches or with tile drains. Proper aeration of the soil about
the roots is essential to enable the date palm to grow well and yield
abundantly (see p. 80). Good drainage also permits the alkali to be
washed out of the soil by means of heavy irrigation, and, doubtless,
this also favors the growth of tho palms. It is, however, worthy of
being noted that the excessively alkaline water which flows off in the
drainage ditches is used in some parts of the Sahara to irrigate date
palms which occupy land lying at a lower level. Such palms, though
According to Mr. Bernard G. Johnson, of Mecca, CaL, there is a drainage of cold
air from the hills toward Mr. Hanlon's date plantation which renders it one of the
coldest sites in the vicinity of Yuma.
DRAINAGE. 51
less vigorous than those receiving good water, nevertheless produce
moderate crops of fruit (see p. 98).
In most date plantations made by the French in the Sahara, drainage
is provided by means of open ditches from 2 to 6 feet deep, running
between alternate rows of palms, or at distances of about 50 feet
apart (see PL XVII, tig. 1). Very unusual conditions of drainage are
found at the oasis Fougala, Algeria (see PL XV, fig. 1), as will be
explained in treating of the alkali soils collected at that place (pp. 78
and 84). The superfluous water there runs off through holes in an
impervious hardpan, and the downward flow of water through the
holes, induced by surface irrigation, has washed the alkali out of the
surface soil, has aerated the subsoil, and has had marvelous effects in
promoting the growth and increasing the yield of the date palms,
which had managed to live for years before surface irrigation was
begun with the supply of water absorbed by the roots from below the
hardpan layer.
It will doubtless be found necessary to irrigate date palms about
Tempe, Ariz. 9 even where their roots penetrate to the subsoil con-
stantly wetted by the water that seeps down from the irrigated fields
located at higher levels. Unless this is done the palms are likely to
become stunted and sterile, as they were at Fougala before surface
irrigation by artesian water was commenced.
The presence of a hardpan layer, as at Fougala, may be advanta-
geous in providing a means of drainage through holes made under each
tree, while at the same time confining the drainage water below the
hardpan, thereby preventing its rising to the surface by capillarity
and carrying with it the alkali of the subsoil. When no hardpan
exists, as at Tempe, a certain amount of drainage can nevertheless be
accomplished, since the water applied at the surface drains into the
great body of ground water, which has a practically constant level
unless raised by excessive irrigation. In case the subsoil is too
impervious to permit quick seepage from the surface to the ground
water, outlets for drainage water can sometimes be provided advan-
tageously by putting down wells.
In most parts of the Salt River Valley the natural drainage is good
and no ditches or tile will be needed. In the Salton Basin drainage is
impeded by the impervious nature of the clay, which occurs in many
places as surface soil and nearly everywhere as subsoil. Drainage is
especially desirable here, for the subsoil is often laden with alkali
even where the surface soil is free from harmful quantities of salts.
Natural drainage, nevertheless, will probably suffice for the date palm
in many parts of this region, provided the level of the ground water
is not raised too high by excessive and ill-timed irrigation. In some
places, where natural drainage is insufficient, occasional open ditches
will provide adequate drainage, especially where the soil is a sandy
52 THE DATE PALM.
loam or a loam. The lands lying near the New River or Salton River
beds, or near Mesquite or Salton Lake, can be drained into these
lower levels, and in many other places wells may be put down to pro-
vide an outlet of drainage water into the great body, of ground water
which lie$ from 20 to 50 feet below the surface. Though required
for the best growth and successful fruiting of the date palm, drainage
is less necessary than for most other trees. Even if the ground water
of the Salton Basin rose to within reach of the roots it would not kill
the date palm, for, although this ground water is very brackish, con-
taining from 0.4 to 0.6 per cent of dissolved salts, and would kill most
ordinary plants, it is less alkaline than some of the artesian water used
to irrigate flourishing date plantations in the Oued Rirh country in
the Sahara (see pp. 86 and 121).
EFFECTS OF ATMOSPHERIC HUMIDITY AND BAIN ON THE DATE
PALM.
An essential requirement of the date palm, in order that it may pro-
duce fruit of the best quality, is that the air be very dry during the
season when the fruit is developing. Regions having abundant sum-
mer rains, and even those having a heavy precipitation in autumn, are
unsuited to the profitable culture of this tree, but rains in winter ma}^
be beneficial. It has usually been held that the presence of humidity
in the air is directly disadvantageous, but it is probable that the chief
action of water vapor in the atmosphere is indirect and results from
its peculiar action in screening out the heat from the sun's rays f/ and
thereby preventing the temperature from going to the excessively
high degree necessary to ripen the fruit properly. The same dry air
which allows excessive heating during the day permits an equally great
fall of temperature by radiation into a cloudless sky at night and
brings about the enormous daily range of temperature characteristic
of desert regions. The date palm, however, suffers no check from
cool nights, unless the temperature falls below a point somewhere
about 18 C. (64.4 F.), and is favored by excessively high temper-
atures, which are, indeed, necessary for the production of dates of the
highest quality.
Table 1, on the following page, gives the mean relative humidity at
four points where the date palm is grown, for the months of April to
September, inclusive.
Very, Frank W. Atmospheric Radiation. Bui. G, Weather Bureau, U. S. Dept.
of Agriculture, 1900.
EFFECTS OF HUMIDITY AND BAIN.
53
TABLE 1. Humidity of the air at four desert stations where dates are grown.
Mean rela-
tive hu-
Mean rela-
Locality.
Altitude.
midity of
six months,
tive hu-
midity of
Remarks.
Apr. 1 to
Sept. 30.
month.
Feet.
Per cent.
Per cent.
frharda'ia, Algeria
BNkra \lgeria
1,804
449
1,068
23
30
33
14 (July)
25 (June)
24 (June)
Dates are of excellent quality. >
Dates are largely grown, but are
not of the best quality. -
Dates of the earlier 'sorts ripen
well.
Phoenix Ariz
Tucson Ariz ....
2,432
35
19. 9 (June)
Dates ripen imperfectly here, pro-
bably because of deficient sum-
mer heat at this altitude; pos-
sibly also because of too great
humidity. 4
1 Records of Dr. Amat for the years 1883, 1888, and 1889.
2 Schirmer, Sahara, p. 64.
3 Records of Weather Bureau Station, completed by A. J. McClatchie, Bui. 37, Ariz. Agr. Ex. Sta.,
p. 209, average of five years' record.
4 Boggs and Barnes,* Bui. 27, Ariz. Agr. Ex. Sta., p. 37, record for the years 1892-1894. The mean
for October is 36,3 per cent.
The following averages show the amount of atmospheric humidit} 7
at Phoenix and Tucson, Ariz., for each month from the flowering to
the ripening of the fruit of the date palm, and a partial record from
GhardaTa, Algeria:
TABLE 2. Mean relative humidity at desert stations during date season.
Average,
Locality.
Length of
record.
April.
May.
June.
July.
Aug.
Sept.
Oct.
Nov.
April to
Novem-
ber.
Phoenix
5 years
33
26
24
37
40
39
40
43
35 25
Tucson
3 vears
28.1
25.5
19.9
42.8
51.8
39.6
36 3
40 2
35 52
Ghardai'a
1 vear (1883)
28 1
37 5
32 3
11 9
14 4
22 1
Do
3 years
23.0
14.0
19.0
The occurrence of a well-defined rainy season in July and August in
southern Arizona causes the humidity for those months to be much
higher than it is in the Sahara, where all three summer months are
very dry.
The following table showing the average rainfall for each month at
Biskra and Ayata in the Sahara, at Phoenix and Yuma, Ariz., and at
Salton, in the Salton Basin, California, brings out this difference in
climate:
TABLE 3. Mean monthly rainfall, in inches, at Biskra, Ayata, Phoenix, Ynma, and
Salton.
Locality.
Jan.
Feb.
Mar.
Apr.
May.
June.
July.
Aug.
Sept.
Oct.
Nov.
Dec.
Year.
Bi kra, Algeria 1 ....
Ayata. Algeria 2
0.52
.08
57
0.64
.27
89
1.38
1.06
68
0.94
1.06
30
0.83
.16
16
0.33
07
0.25
85
0.26
97
0.57
.04
54
0.64
.12
62
0.93
1.21
44
2.17
.53
1 12
9.46
4.53
7 21
Yuma, Ariz
Salton, Cal. 4
.40
.43
.54
.62
.24
.21
.07
T.
.04
.07
T.
T.
.14
.19
.37
.14
.14
.13
.30
.12
.28
.12
.53
.56
8. OR
2.56
1 Records of M. Colombo, published by Marcassin in Annales de 1'Inst. Nat. Agronom., 1895, 10 years.
-'Records of M. Cornu, read from charts exhibited at Paris Exposition. 1900. 4 years.
^Records of the Weather Bureau, compiled by Thos. H. Means, Second Rep., Div. of Soils, U. 8.
Department of Agriculture, 1900, p. 292.
* Records of the Weather Bureau, compiled by Prof. Alexander G. McAdie, California Climate and
Crop Service, April, 1901, 12 years.
54 THE DATE PALM.
During- July and August more than three times as much rain falls at
Phoenix as at Biskra, although the annual rainfull is nearly one-third
greater at the latter station.
Unfortunately records are not available for the Salton Basin, but
the very low rainfall in spring, summer, and autumn, and the exces-
sively high temperatures which prevail there render it certain that the
humidity is very slight probably somewhat lower than at Gharclai'a.
There is, however, as in Arizona, a well-defined rainy reason in July
and August, which tends to raise the humidity for those months.
RAINY WEATHER DISASTROUS TO THE FLOWERS AND RIPENING FRUITS
OF THE DATE PALM.
Besides its indirect harmful action in decreasing the amount of sun-
shine and heat and in increasing the amount of humidity in the air,
cloudy or rainy weather is directly injurious to the date in preventing
the fertilization of the flowers in spring, and also in bringing about
the decay or dropping of the fruit when it is ripening in autumn.
When the flowers are being pollinated a spell of wet, cloudy weather,
by spoiling the pollen may hinder the setting of the fruit, though
usually the harm can be remedied by repollinating with a fresh spray
of male flowers when the weather becomes dry. In autumn the effects
of rainy, humid weather are much more disastrous and may entail the
loss of the entire crop by causing the dates to ferment and spoil just
when they are ripening. No misfortune is more feared by the date
growers in the Sahara than wet weather at this time.
Most varieties of date palms flower in April and May in Arizona, as
in the Algerian Sahara, and the best sorts begin to ripen in October
and November. The following table shows the amount of rain for the
months of April and Ma} r , in spring, and October and November, in
autumn, for a number of points in the Southwest, and also for Biskra
and Ayata in the Sahara.
RAINY WEATHER DISASTROUS.
55
TABLE 4.Arerage, highest, mid lowest rainfall, in inches, at flowering and ripening seasons
of the date palm at stations suitable for date culture.
Locality.
Alti-
tude.
Rainfall during flowering season.
April.
May.
Mean.
Maxi-
mum.
Mini-
mum.
Mean.
Maxi
mum.
Mini-
mum.
Phoenix, Ariz. (Salt River Vallev) 1. . .
Feet.
1,068
900
1,110
1,200
1,244
Indies.
0.31
Tr.
.09
Tr.
Inches.
1.25
Inches.
Inches.
0.16
.09
Inches.
1
Inches.
Buckeve (Salt River Vallev) 2
Experiment Farm (Salt River Valley) 2
Peoria (Salt River Valley) 2
.18
Mesa (Salt River Valley) 2
o
Average for five stations in Salt River
Valley
.08
.086
Maricopa.Ariz. (Upper Gila Valley)
Casa Grande (Upper Gila Valley) l
i
1,
1,
1
173
39S
553
.13
.11
.37
.75
.73
1.55
.10
.07
.18
.64
.34
.97
Florence (Upper Gila Valley) J
Tucson, Ariz. 1
2
430
141
.16
.07
.62
.55
.18
.04
1.09
.44
Yuma, Ariz. 1
Mammoth Tank, Cal. (Salton Basin) *
Salton, Cal. (Salton Basin) 3
257
-263
.06
Tr.
.80
.01
.02
.07
.30
.70
2756"
Biskra, Sahara 4
449
.94 3.03
.08
.83
ToT
Ayata, Sahara (Oued Rirh) 5
100
1.06
2.24
.16
.47
Locality.
Rainfall during ripening season of
late dates.
Rainfall during
year.
Length
of
record.
. October.
November.
Mean.
Max.
Min.
Mean.
Max.
Min.
Mean.
Max.
Min.
Phoenix, Ariz. (Salt River Valley) .
Buckeye (Salt River Valley) 2
In.
0.50
.63
In.
2.80
In.
In.
0.44
.42
In.
1.66
In.
In.
7.08
6.60
In.
12.83
In.
3.77
years.
15
Experiment Farm (Salt River Val-
ley) -
.34
.48
7.01
Peoria (Salt River Valley) 2
.92
40
8.41
5.52
Mesa (Salt River Valley) 2
.31
.46
Average for five stations in
Salt River Valley
.54
.44
6.94
Maricopa, Ariz. (Upper Gila Valley) l
Casa Grande (Upper Gila Valley) l . .
Florence (Upper Gila Valley) 1
.28
.32
.63
1.51
1.81
1.80
000
.29
.33
.55
1.13
2.00
2.36
5.50
5.29
9.78
11.96
10.70
13.80
.88
1.73
5.35
18
14
13
Tucson Ariz *
.53
.30
2.24
1.70
.48
.28
2.06
2.43
11.63
3.05
18.37
5.86
5. 26
.74
19
19
Yuma, Ariz. l
Mammoth Tank, Cal. (Salton Basin)'
Salton, Cal. (Salton Basin) 3
.12
.12
.68
.93
.14
.12
.73
.71
1.81
2.56
5.48
11.19
16.30
Tr.
Tr.
23
12
Biskra, Sahara 4
.64
1.73
~93
1.97
.12
9.46
4.89
5.67
10
Ayata, Sahara (Oued Rirh) 5
.12
.28
1.21
2.05
.02
9.32
2. 52
4 and 7
1 Records compiled by Boggs and Barnes, Bui. 27, Arizona Experiment Station. Table XVI.
'-Records compiled by Thos. H. Means, Field Operations Divison of Soils, U. S. Department of
Agriculture, Second Report, 1900, p. 292.
3 Reeords compiled by Alexander G. McAdie, Cal. Sec., Climate and Crop Service, Weather Bureau,
February, 1901, p. 4.
'Records of Colombo, published by Marcassin, L' Agriculture dans le Sahara de Constantine, in
Annales de I'lnstilut National Agronomiqoe, 1895, p. 17 of reprint.
5 Records of Cornu tor years ls%-ls<), rend from charts exhibited at Paris Exposition. 1900.
6 Annual rainfall for 1889 to 1891, from Rolland, Hydrologie du Sahara nlgericn, p. ll.~>, is included
11 this table, making seven years in all.
These records show that the Salt River Valley, the upper Gila Val-
ley, Yuma, and even Tucson, Ariz., have less rainfall at the critical
periods for the date palm than occurs at Biskra, Algeria, where date
culture is the principal industry. Yuma, in the Colorado River
56
THE DATE PALM.
Valley, in extreme southwestern Arizona, and especially Salton and
Mammoth Tank, in the Salton Basin, in southeastern California, show
decidedly less rainfall than occurs at Ayata, in the Oued Rirh country
in the Sahara, where date culture is almost the sole industry and
where the Deglet Noor variety is grown successfully. Even the maxi-
mum rainfall in exceptionally wet years in the Salton Basin does not
equal a the average rainfall for these critical months at Biskra.
The number of rainy days, which is a matter of considerable import-
ance in determining the suitabilit}^ of climate to date culture, runs
closely parallel to the amount of precipitation, as may be seen by com-
paring the following records for Biskra and Tucson with those given
above for the rainfall:
TABLE 5. Number of rainy days at desert stations (Biskra, Algeria, and Tucson, Ariz.)
during flowering and ripening seasons of the date palm.
M
Flowering season.
Ripening season.
o> .
April.
May.
October.
November.
Locality.
1
O>
>>
a
a
a
|
a
d
a
3
a
I
a
a
a
d
a
a
c
I
a
j
a
a
2
j
1
B
cS
1
1
1
i
1
1
|.
i
1
5
Biskra, Algieria..
449
10
3.4
7
i
3.5
6
i
2.6
5
8.6
7
1
Tucson, Ariz
2,432
5
.2
1
1.2
3
4.8
9
.2
6
The ideal climate for the date palm would be one that was rainless
during the critical months. It is a matter of some interest to see how
often this condition has been recorded for the Salton Basin stations.
Rainfall records are available for twelve years (1889-1900) for Salton
in the lowest part of the Salton Basin (263 feet below the sea level),
and they show that the critical months were frequently rainless; at
Mammoth Tank, in the eastern border of the Salton Basin (altitude
257 feet above sea level), the record for twenty-three years, from 1878
to 1900, is still more favorable, as is shown by the following table:
TABLE 6. Number of years in which no rain (or trace only) fell at Salton and at Mam-
moth Tank, in the Salton Basin, California, during the months named.
Month.
Salton (263 feet be-
low sea level).
Mammoth Tank
(257 feet above
sea level).
Number
of years
rainless.
Total
number
of years
recorded.
Number
of years
rainless.
Total
number
of years
recorded.
April...
11
10
9
8
8
7
12
12
12
12
12
12
14
20
13
12
13
7
23
23
23
23
23
23
May
April and May ... . . .
October
November
October and November . .
Except for one year of the twelve recorded at Salton, the rainfall in October, 1896,
was 0.93 inch, exceeding the average at Biskra (0.64 inch), though not being more
than half the maximum rainfall for the month ( 1.73 inches) at the latter station.
RAINY WEATHER DISASTROUS.
57
At Salton, out of the twelve years recorded, only one had more than
one-tenth of an inch of rain during the two months of the flowering
season (April and May) and only two had over 0.28 inch rainfall
during the ripening season.
At Mammoth Tank, out of these twenty-three years, only one had
more than three-tenths of an inch rainfall during the flowering
season (April and May) and only three showed over three-tenths of an
inch precipitation during October and November.
At Biskra, in the Algerian Sahara, the rainfall records are available
for the ten years from 1884 to 1893. During this period only one
month during the critical periods was rainless, viz, October, 1893.
Only once during the flowering period (April and May) was there
as low as 0.39 inch rainfall, and only once during the season when the
fruit ripens (October and November) was there as low as 0.31 inch of
rain.
At Ayata, some 100 miles south of Biskra, in the Oued Rirh country,
where a specialt} r is made of the culture of choice Deglet Noor dates
for the export trade, the rainfall for 1889 was 2.52 inches; for 1890 it
was 9.32 inches; for 1891, a 4.16 inches; for 1896, 7.60 inches; for 1897,
4.84 inches; for 1898, 2.79 inches, and for 1899, 6 2.91 inches, an aver-
age of 4.89 inches.
The distribution of the rainfall at Biskra and Ayata, by seasons, in
comparison with the average at Yuma in the Colorado River Valley
and Salton and Mammoth Tank in the Salton Basin, is given herewith:
TABLE 7. Table showing seasonal and annual rainfall at stations in desert regions.
Locality.
Length
of
record.
Winter
rainfall.
Spring
rainfall.
Summer
rainfall.
Autumn
rainfall.
Annual
rainfall.
Biskra Algeria (Sahara)
Years.
10
Inches.
3 32
Inches.
3.16
I in-lit*.
O.H4
fneka,
2. 13
Inches.
9.45
Ayata Algeria (Sahara)
7
1.81
1.49
".09
1.50
4.89
Yuma, Ariz. (Colorado River Valley)
Salton Cal (Salton Basin)
19
12
1.47
1.59
.35
.28
.51
.33
.72
.37
3.05
2.56
Mammoth Tank, Cal. (Salton Basin)
23
.93
.27
.29
.32
1.81
a During the years 1896 to 1899 almost no rain fell in summer. April, May, September, and October
are sometimes rainless.
It is noticeable that the summer rainfall is considerably higher at
Yuma and at the Salton Basin stations than at Ayata, but that the
spring and autumn precipitation is much less, rendering the climate
decidedly more favorable for date culture.
It is clear from the above tables that there is less danger from rain
to date flowers or to the ripening fruits in the Arizona deserts or in
the Salton Basin in California than at Biskra in the Algerian Sahara,
where date culture is an established and profitable industry. Indeed,
Holland. Hydrologie du Sahara, p. 416. For the years 1889 to 1891, inclusive.
& Records of Cornu exhibited at Paris Exposition, 1900. Amounts read from curves
of charts for the years 1896-1899.
60 THE DATE PALM.
than on the tops of old palms far above the surface. Old and vigor-
ous trees might perhaps occasionally weather cold snaps where the
temperature fell below 10 F., provided such were exceptional and
occurred only at intervals of many 3^ears. In practice, then, four dif-
ferent limits below which palms would be injured by cold might be
set: (1) Young palms in active growth would be liable to injury if the
temperature fell several degrees below freezing; (2) 3 7 oung plants not
in active growth and old palms if nearly dormant would be severely
injured only by temperatures falling below 15 F. ; (3) old and dor-
mant trees would be severely injured only by temperatures below 12 F. ;
(4) most date palms would be killed and all would be seriously injured
by the temperature falling below 10 F. , and date culture would be
impossible in regions where such temperatures occurred more than once
in a decade. These considerations show that the date palm has about as
much resistance to cold as the fig tree, for example, with this impor-
tant difference that a fig tree is able to recover and grow again the next
year, even if it be frozen to the ground by severe cold in winter.
With the date palm this is not possible, since, if the growing bud of an
old tree be killed, it is impossible for the trunk to sprout out again.
In the Salt River -Valley, Arizona, the temperature not infrequently
falls to 25 or 22 F., and at rare intervals goes as low as 12 or 13
F., which temperatures of course injure the date palm but have not
killed any of the many fine trees growing in the valley, though young
offshoots recently transplanted have been frozen to death a .
No temperatures low enough to injure seriously even young date
palms (below 18 F.) are recorded from any of the stations in the Sal-
ton Basing and if the first winter after the plants are set out is passed
safely no further danger from cold need be feared.
a Even young palms seem more resistant to cold than has been supposed, for the
severe cold of the winter of 1901-2, when a temperature of about 13 F., was reached,
killed very few of the Saharan date palms in the cooperative garden at Tempe, which
were planted in July, 1900. A few of the offshoots set out in 1901 passed through
the cold weather without being killed, thanks probably to the protection afforded by
wrapping them in several thicknesses of burlap sacking. It is now very clear that
large offshoots withstand cold much better than small ones and besides bear the
long voyage better.
&The lowest temperature recorded at Salton is 20 F., with 22 F. at Mammoth
Tank, where only 9 out of the 23 years recorded show temperatures below 30 F.
At Indio in the northern and at Imperial in the southern part of the basin temper-
atures of 18 F. are recorded. At Indio the temperatures are probably lowered by
cold winds which blow down from the mountains to the north and west through a
valley-like prolongation of the desert to the northwest. The young date palms
which grow about Indio without any protection are proof that the winters are not
too severe even for very young plants. However, winter cold is the greatest danger
to which the date palm is exposed in the Salton Basin, and intending planters should
be careful to avoid low, cold situations in setting out date palms, for Snow reports
on January 2, 1902, at 8 o'clock a. m., a temperature of 13 F. and ice 2 inches thick.
(Bui. 140, Cal. Exp. Sta., p. 45.) A. V. Stubenrauch states that this record is for
Imperial, Cal.
LATE FROSTS AND DRAINAGE OF COLD AIR. 61
THE DATE PALM FLOWERS LATE IN SPRING AND ESCAPES INJURY
BY LATE FROSTS.
A very great advantage of the date palm is that it flowers late in
spring, after all danger of frost is over," whereas many other fmit
trees, among them the peach, the apricot, and especially the almond,
bloom very early and are exposed to much risk of having the flowers
or } T oung fruits killed by late frosts.
The records available from the Sahara are very poorly calculated to
show how much cold the date palm can stand, for the whole northern
and western Sahara is characterized by very warm winters. Tempera-
tures of 5 to 7 C (21.4 to 23 F.)are recorded from date oases in the
Sahara, but the date palm is able to endure lower temperatures than
these without serious harm resulting. The northern limit and the
limit in altitude in northwestern Africa at which dates can be grown
are set more by the deficient summer heat failing to ripen the fruit
than by the cold in winter. 6
DRAINAGE OF COLD AIR AND INVERSION OF TEMPERATURE IN
RELATION TO DATE CULTURE.
A peculiarity of climate which is of considerable importance in
relation to date culture is the inversion of temperature which occurs
in many places in Arizona and California, and more markedly in arid
regions where the date palm succeeds best. For example, in many
parts of Arizona the winters are mild enough to permit date palms to
be grown at an altitude of nearly 5,000 feet, and even as high as 6,942
feet at Supai. It is noticeable, however, that points very much lower
frequently show temperatures sufficiently cold to injure severely or to
kill date palms. For instance, at San Carlos, at an altitude of 2,456
The pistache nut has the same advantage and can be grown with profit in place
of the almond in many localities where the latter is likely to lose its fruit because of
late frosts.
&It is probable that the date palm is hardier than has been supposed, and that by
selecting hardy sorts and wrapping them well when young, date culture can be ex-
tended to many of the desert regions in the Southwest hitherto supposed to be too
cold in winter for this plant. The experiments at the date garden at Tulare have
shown that there is a great difference in the resistance of the various sorts to cold, the
Seewah at an age of 9 years being, for instance, 12 feet high, with a spread of leaves
of 15 feet, while the Sultaneh, equally old but which had been much hurt by the cold
winters was only 4 feet high, with a spread of leaves of 7 feet. The experience of the
winters of 1901-1902 at Tempe, Ariz., has shown that recently transplanted offshoots
are hardier than has been supposed. It now becomes a matter of much importance
to procure hardy sorts of date palms (probably best to be secured in the oases of Per-
sia and Baluchistan) for planting in the deserts in the south western United States which
have hot summers but cold winters. Fort Mclntosh, altitude 460 feet, in south-
western Texas, and Fort Thomas, altitude 1,600 feet, in the valley of the Virgin River
in southern Nevada, both have a summer climate hotter than that of Phoenix, in the
Salt River Valley, Arizona, but at- the same time colder winters. Late sorts of dates
of good quality could be matured at these places provided they could pass the winters
unharmed (see pp. 126 and 134).
62 THE DATE PALM.
feet, and at Tucson, at the University weather station, at an altitude
of 2,230 feet, the temperature fell to 11 F. in 1891, while at Dragoon
Summit, at about 4,611 feet altitude, some 60 miles to the east of Tucson
and 80 miles southwest of San Carlos, the temperature is not recorded
even as low as 15 F. in 1891. a In January, 1891, the temperature did
not fall below 32 F. at Dragoon Summit, while at Wilcox, only 20 miles
northeast, and nearly 500 feet lower, the temperature fell to 9 F. A
still more striking example is shown by a comparison of the temperatures
at Parker, on the Colorado River, at an altitude of about 500 feet, and at
Supai, nearly 7,000 feet above sea level, some 120 miles to the north-
east. In the winter of 1899 and 1900 the temperature did not fall
below 26 F. at Supai, while the imperfect record at Parker shows a
minimum of 23 F., that is to say, that although Supai is nearly 6,500
feet higher than Parker and is about 65 miles farther north, the min-
imum temperature was actually higher at Supai in winter. Numerous
similar instances could be cited in California, and the "thermal belt"
along the foothills of the Sierra Nevada Mountains, adjoining the
interior valley region, offers some of the most striking examples that
are known of inversion of temperature.
All of these anomalies are the result of a drainage of cold air to
lower levels. During the night, if radiation is unhindered by clouds,
as is usually the case in arid regions, the air next the ground is cooled
rapidly and flows from the higher levels into the valleys below, much
as water would. As the cold air flows into the plains it 'doubtless
tends to flow under and to lift up the warm air; at any rate, all eleva-
ted points where there is a good drainage of air show relatively high
temperatures during the night, while points located in the valley floor
frequently show very low temperatures, constituting an exception to
the general rule that the lower the altitude the higher is the tempera-
ture. It will frequently be possible to grow date palms along the
foothills where it would be impossible for them to succeed in the
plains a few hundred feet below.
However, high summer temperatures are essential to the proper
fruiting of the date palm, as will be shown in the next paragraph, and
the upper limit in altitude of its culture is more likely to be set by
the insufficient heat of summer than by the severit}" of cold in winter.
At points situated at high altitudes, whence there is a good drainage
of air, the fluctuations of temperature are less than in the plains
below, and consequently the winters are warmer and the summers are
cooler. In order to grow date palms at high altitudes, it will usually
be necessary to search for canyons or ravines with a southern expo-
sure, where the air is heated by reflection from mountain cliffs as well
as by direct insolation.
All the-data as to temperature at: the various points named are from the reports
of the Weather Bureau and of the State weather services of California and Arizona.
HOT SUMMERS NECESSARY. 63
HOT SUMMERS NECESSARY FOR THE DATE PALM.
Date palms require a definite sum of heat in order to mature their
fruit properly, but the amount varies greatly for different sorts. In
general the very early ripening kinds are watery and unfit for drying,
being more like table grapes than like ordinary dates. They can le
grown far to the north where the summers are not warm enough to
ripen later varieties. The Wolfskill is such a date (see fig. 3, p. 31).
The sorts ripening in inidseason can often be dried, but lack the sweet-
ness and exquisite flavor of the late sorts, such as the Deglet Noor
(see p. 33). The late sorts, and especially the one just named, require
enormous amounts of heat in order to ripen properly. The Deglet
Noor date is produced in the oases of southern Algeria and southern
Tunis, where fortunately there are well equipped meteorological sta-
tions whose records furnish a basis for a comparison of the climate
there with that of American deserts, so far as records are available for
the latter.
It has been calculated by De Candolle 05 that temperatures down to
18 C. or 6-1.4 F. have no effect on the flowering or fruiting of the
date palm, and a study of the record sheets of a self-recording ther-
mometer kept at Biskra in the midst of a date orchard confirmed
the correctness of this assumption. In other words, this relatively
high temperature is the zero point for this plant, so far as flowering
and fruiting are concerned, though it is able to grow at somewhat lower
temperatures. The curves shown in the accompanying diagram (fig. 7)
represent in a manner plain to the eye the heat conditions of Biskra,
Algeria, in the northern part of the Sahara Desert, in comparison with
those of Sal ton, in the lowest part of the Salton Basin.*
The curves highest up in the diagram represent the mean maximum
temperatures, the curves in the middle show the mean temperatures
a Geographic botanique raisonnee, I, p. 371.
& The curves for Biskra for maximum and minimum temperatures are based on
averages of twelve one-half years' observations by M. Colombo, summari/ed by
Snpan (Petermann's Mitth., Vol. 32, 1886, Lit. ber., p. 32); forthe mean temperature,
on ten years' observations by Colombo, published by Mareassan (Ann. de 1'inst. riat.
agronom., Paris, 1895). The curve for the maximum temperature for Salton is based
on the record for two selected years, 1893 and 1899, each having nearly the same sum
of heat for the fruiting season, from May to October, inclusive, as the average of the
t \\ fl ve years recorded. Prof. Alexander G. McAdie, director of the Pacific coast divi-
sion of the Weather Bureau at San Francisco, kindly furnished the records, as yet
unpublished, for these years. This curve is smoothed a little and is somewhat lower
than the true mean maximum, as it is based on observations taken at 2 o'clock p. in.,
which do not always give the highest temperature which occurs during the day.
The curve for the mean temperature at Salton is based on twelve years' observations
published by Professor McAdie. (California Section, Climate and Crop Service,
Weather Bureau, February, 1901, p. 4.) The curve forthe minimum temperatures
for Salton is not based on any observations, as the minimum temperatures are not
available; the mean minimum temperatures are estimated to be as far below the mean
temperatures as the mean maximum temperatures are above.
64
THE DATE PALM.
of the whole day, and the curves lowest in the scale show the mean
minimum temperature. In every case the dotted lines represent the
record for Biskra and the unbroken lines that for Salton. The months
of the year are marked off horizontally and the degrees of heat are
shown by the height of the curve from the base. The temperatures
can be read off in Fahrenheit at the left and in Centigrade at the right.
The heavy black horizontal line represents the zero point for the flow-
ering and fruiting of the date, 18 C. (64.4 F.).
It is evident from the first glance at the curves that Salton is much
hotter than Biskra and that the daily range of temperature is much
greater, and as a consequence that the mininum is lower in winter,
at the same time that the mean temperature is higher.
FAHR
JAN.
FEB.
MAR.
APR.
MAY
JUNE
JULY
AUG.
SEPT.
OCT.
NOV.
DEC.
CENT.
-H*
110-
$$s
^X^
c&r
s.
^
&<
/''
"^x^
\
$r
&y
^-
i^
N J
k
\V
ys
b v '' /
2s
>
N.
*2
E3E2-
Ss \
\
/
A*
^/
^
\ k \
\
/
~3jjS3
^
' -tf\ltt
ft^^^
\
\
/
M
W%L_.
Itffej
8_
^\
N N
\
\
80-
s'
y ,<
gag
Hf^t
S. v^
3S
\
75*
^^
//
$''4
%Z&
****..
\
v X^
\
-26"
""
-''
/
22|
jjJL
X s
\ >
s
^
/
s
tf$fad
\
\ \
\ ^x^
^**
/
,'
$4)''
Zero r<
\>r cUztt
palm
N \\
\
X
/ ,*-
' /
s
\\
V s. \
^
f s
//'
\ x
^ V x^
V
55-
/,'
IS
\
X ^*--
60
--
+/'
x \
^->
12
-10
~^_
'/
\^
x ^
/
V ""
/
\
, -*
^x>
FIG.
7. Curves representing the average maximum, mean, and minimum temperatures at Salton,
Cal., and at Biskra, Algeria.
The zero point for the date palm, 18 C. (64.4 F.), is reached by the
mean temperature about April 5 at Biskra, while it is passed fully
three weeks earlier at Salton, or about March 12. The mean daily tem-
perature rises more rapidly at Salton than at Biskra, which brings about
the result that the period when the date palm flowers, which accord-
ing to Fischer's calculations^ is when the mean daity temperature is
between 20 and 25 C. (68-77 F.), extends from about April 20 to
May 20 at Biskra, whereas at Salton it extends from about March 23
to April 20; that is to say, if Fischer's calculations are correct, the
date palm will flower about a month earlier at Salton than at Biskra,
Fischer, Th. Die Dattelpalme, ihre geographische Verbreitung und culturhistor-
ische Bedeutung. In Petermann's Mitth., Ergiinzungsheft No. 64, Gotha, 1881, p. 51.
HEAT REQUIRED TO MATURE FRUIT. 65
although the zero point for this plant is passed by the mean tempera-
ture only three weeks earlier.
The mean temperature at Biskra usually remains above 18 C.
(61.4 F.) from about April 5 until about November 3, some 212 days,
or nearly 7 months. At Salton the period having a mean temperature
above 18 C. extends from about March 12 until about November 20,
or some 253 days, nearly six weeks longer than at Biskra. As has
been already stated, the flowering season will probably begin a month
earlier at Salton than at Biskra because of the abrupt rise of temper-
ature in spring, and as the mean temperature remains above 18 C.
(6i. 4 F.) nearly a month and a half longer in autumn, the season is
nearly two months and a-half longer, and, moreover, is decidedly
hotter throughout. It is evident that if the Deglet Noor date can
mature at Biskra it can certainly ripen perfectly at Salton.
AMOUNT OF HEAT REQUIRED TO MATURE THE DATE.
The comparison of the sums of the daily mean temperatures gener-
ally employed in determining the heat requirements of plants can be
made only between regions having a somewhat similar climate, and
some botanists have gone so far as to deny entirely that any trust-
worthy conclusions as to the development of a plant can be drawn
from estimates of its heat requirements. To say that the sum of heat
decides when a plant flowers or when its fruits ripen has been held to
be equivalent to asserting that the other factors of equally vital
importance to the plant, such as the amount and nature of its food
supply, the supply of water, the amount of light, etc., have no appre-
ciable influence on its development. This criticism doubtless has
much force in the case of humid regions, where a variable and capri-
cious rainfall greatly influences the growth of vegetation. In rainless
deserts, however, where all cultivated plants are watered artificially
and where the sunshine is almost uninterrupted by clouds, the sum of
heat becomes a factor of predominant importance in the life history of
plants, and consequently comparisons between similar desert regions
in respect to their adaptability for any given cultures may very prop-
erly be made by determining the sum of heat for the critical periods
of the plants in question.
The amount of heat necessary to ripen the fruits of the date palm
has generally been calculated by adding together the daily mean tem-
peratures during the months when the dates are developing, generally
from about May 1 until October 31, six months in all. In this bulletin
the sum above 18 C. is counted for greater convenience in making
comparisons, though generally the sum is reckoned from C. The
table on the following page gives the summation of effective tempera-
tures during the fruiting season of the date palm for a number of points
in North Africa and in the Southwestern States.
13529 No. 5304: 5
66
THE DATE PALM.
TABLE 9. Sum of daily mean temperatures above 18 C. (64.4 F.) for fruiting period of
date palm from May 1 to October 81, at the stations named.
Locality.
Sum of daily mean
temperatures above
18 C. (64.4 F.) from
May 1 to October 31.
Remarks.
Degrees
centigrade.
Degrees
Fahrenheit.
Algiers Algeria
652
788
1,054
1,409
1,593
1,677
1,836
1,816
1,906
2,091
2,049
2,356
2,237
2,348
2,585
2,074
2,679
3,392
2,749
2, 106
1,174
1,418
1,897
2,538
2,868
3,019
3,304
3,269
3,431
3,764
3,689
4,242
4,027
4,227
4,652
3,734
4,823
6,106
4,948
3,791
No dates ripen here.
Very early sorts mature.
Average of many years' observations. Dates of
sorts grown usually fail to ripen.
Average of 6 years' observations. Dates of the
sorts now grown usually fail to ripen.
Dates ripen regularly.
Average of many years' observations. Many
sorts of dates ripen regularly.
Average of 10 years' observations. Many sorts
of dates ripen regularly; date culture the lead-
ing industry. Deglet Noor dates ripen but
are not of the best quality.
Deglet Noor dates ripened very imperfectly.
Deglet Noor dates ripened very slowly and im-
perfectly.
Deglet Noor dates ripened well.
Do.
Average of 5 years' observations. Many excel-
lent varieties ripen.
Average of several years' observations.
New thermometers. 1
Average of 23 years' observations.
The coolest summer recorded. Observations
taken for the first time with standard Weather
Bureau thermometers in the regulation shel-
ters, i
Average of 12 years' observations.
Hottest summer recorded at Salton.
Orleansville Algeria
Fresno Cal . .
Tucson Ariz
Phoenix, Ariz. (Salt River
Valley).
Biskra, Algeria (Northern
Sahara).
Ayata, Algeria, 1890 (Oued
Rirh region), Sahara.
Ayata 1891
Ayata 1889
Tougo'urt, Algeria (Oued
Rirh region) .
Bagdad Mesopotamia
Indio, Cal. (Salton Basin) ...
Iiidio 1903 . .
Mammoth Tank, Cal. (Salton
Basin).
Salton, Cal., 1903 (Salton
Basin).
Salton mean
Salton 1897
Salton 1902
Imperial, Cal., 1902 (Salton
Basin).
i Until 1903 the temperature records in the Salton Basin were taken by voluntary observers from
thermometers exposed without proper shelters. Mr. Bernard G. Johnson, who lives in the Salton
Basin between Salton and Indio, Cal., writes as follows:
" Formerly there were used cheap thermometers, placed at Indio in the shade of cottonwood trees,
at Salton under an overlapping roof, and at Volcano Springs under a roof that was but slightly over-
lapping. Now they have standard thermometers placed in regulation thermometer shelters, and
hence the difference."
As might be expected, the older records taken at Volcano Springs proved to be much too high, at
Salton still too high, though somewhat nearer normal, and at Indio normal or somewhat too low
when compared with the records taken in 1903 with properly protected thermometers.
Station.
Month.
Mean
temper-
ature for
1903.
Depar-
ture
from
normal
average.
Station.
Month.
Mean
temper-
ature for
1903.
Depar-
ture
from
normal
average.
April
F.
69 4
F.
9 5
Indio
June .
F,
91.1
J
2.8
Salton
...do..!
72.6
-3.9
Volcano Springs . .
July....
90.9
-10.4
do
72.6
+0.1
Salton
...do....
87.8
-11.1
May
78 5
8 3
do
94.4
0.1
Salton
do
79.1
4!o
Volcano Springs . .
August .
95.2
- 3.5
Indio
do
81.0
+0 9
Salton
...do....
94.2
- 3.0
88 5
7 9
Indio .
...do....
93.1
- 0.1
Salton
...do....
89.4
-4.4
Mr. Johnson queries: " If this year, for example, May was 8.3 degrees cooler than the average at
Volcano, why was it only 4 degrees cooler at Salton, 24 miles west of Volcano and at the level of the
valley, while it was 0.9 degree warmer 24 miles farther west at Indio? "
Nevertheless, the sum of the daily mean temperature from May 1 for 1903 was still enough to
'mature the Deglet Noor date perfectly.
A further proof of the greater sum of heat in the Salton Basin, as compared with the Salt River
Valley, is given by Mr. Johnson, who states that cantaloupes ripen at least fourteen days before the Salt
River Valley melons at Mesa, Ariz., and that, too, before the really hot weather begins, which occurs
about the first week in June. Mr. Johnson observes that if the same proportion continues, the grow-
ing season up to November 1 would give about six weeks advantage over Salt River Valley. Now
the Deglet Noor date nearly matures at Tempe in the Salt River Valley and will surely ripen where
it will receive such a considerable sum of heat more than in the Salt River Valley.
HEAT REQUIRED TO MATURE FRUIT. 67
The records taken at Ayata, rt Algeria, in the Oued Rirh country,
are of particular interest. The Deglet Noor date is there grown
largely for export and the meteorological observations are taken in an
oasis largely planted to this variety. Even here in the interior of the
Sahara Desert (see map, PI. II, p. 76) the summers are frequently too
cool to permit this choice date to ripen properly. From three years'
observations it is considered that about 2,000C. are required to ripen
the Deglet Noor date satisfactorily. At Biskra the Deglet Noor is
grown, but does not attain the superatively good quality which has
made the dates of the Oued Rirh famous. 6 It will be noticed that
Phoenix is somewhat cooler than Biskra, making it doubtful whether
this date will ripen there in ordinary seasons. On the other hand,
there can be no doubt about the Salton Basin stations being hot enough
to bring Deglet Noor dates to maturity, even at Indio, in the northern
edge of the basin, and at Imperial, while at Salton the sum of heat
during the coolest summer recorded there was greater than the average
sum for Tougourt, and almost the same as the maximum sum for an
exceptionally hot summer at Ayata, when the Deglet Noor matured-
perfectly. There can then be no doubt that the Deglet Noor date will
ripen fully in the Salton Basin, even when the season is exceptionally
cool. The importance of this demonstration can scarcely be overesti-
mated, since it renders it possible to establish in America the culture
of this choice date, the most expensive of dried fruits, with certainty
of success.
The date palm requires very high temperatures, very much higher
than those recorded by thermometers exposed in the shade, and to
measure accurately its heat requirements it will probably be necessary
to devise a thermometer which can be exposed to the sun and which
will indicate the temperature reached by the leaves. Accordingly a
summation of the maximum temperature was made for the days from
May 1 to October 31, which it is thought will give a better idea of the
adaptability of a climate for date culture than does the sum of the
daily mean temperatures. In making this summation 18 C. (64.4 F.)
was taken as the zero point, as in the preceding table, and when the
daily minimum fell below that point a deduction was made for the
temperatures below the zero point, where they were considered as
being a setback c and as preventing the observed maximum tempera-
ture from causing the growth or development it would otherwise have
done.
Holland, Georges. Hydrologie du Sahara algerien, p. 416.
& In the oasis of Chetma, near Biskra, the Deglet Noor date is said to ripen per-
fectly, thanks to the warm spring water with which the oasis is irrigated (see p. 49).
c For example, the mean maximum for October at Biskra is 27.4 C., or 9.4
above 18 C.; the mean minimum is 16.2 C., 1.8 below 18 C. Now 9.4 is 83.93
per cent of the total daily range of 11.2, and so instead of counting 31 X9.4=291.4 as
the sum for the month, only 83.93 per cent of this sum is counted, or 244.57 C.
68
THE DATE PALM.
The following table gives the results of such a summation of mean
maximum temperatures from a number of points where date palms
grow or can be grown:
TABLE 10. Sum of daily maximum temperatures above 18 C. (64.4 F.) for dale season,
May to October, inclusive, at the stations named.
Locality.
Sum of daily maxi-
mum temperatures.
Remarks.
Degrees
centi-
grade.
Degrees
Fahren-
heit.
Algiers Algeria
1,482
2,002
2, 337
2,593
2,662
3,049
3,068
3,295
3,666
3,990
3,898
4,059
4,010
3,931
2,667
3,604
4,243
4,668
4,773
5,489
5,523
5,932
6,599
7,182
7,017
7,306
7,218
7,077
No dates ripen. Records by Angot (Meteor.
Alger.) .
Very early dates can ripen. Weather Bureau
records, 1897-1900.
Date culture practiced, but dates inferior.
Records by Angot.
Early sorts can be matured . Records by Angot.
Early sorts can be matured. Records' of Uni-
versity of Arizona, 1892-1897.
All sorts of dates grown. Deglet Noor dates not
of best quality. Records of Colombo for 12
years.
Many seedling dates mature: some sorts are too
late to ripen fully. Records of Weather Bu-
reau, 1897-1900.
Deglet Noor matures well if summers are hot;
ripens imperfectly during cool years. Rec-
ords of Cornu for four years, 1896-1899, read
from charts exhibited at the Paris Exposi-
tion, 1900.
Deglet Noor dates are grown for export. Rec-
ords of Angot.
Interior of Sahara, one of hottest stations
known. Datesareextensivelygrown. Records
from Tourney, Bui. 29, Arizona Agr. Exp. Sta.
Average of 5 years' records, published by Will-
cocks. (Fairchild, Bui. 54, Bureau of Plant In-
dustry, U. S. Dept. of Agriculture, 1903, p. 10.)
Unpublished records for 1893 and 1899 furnished
. by courtesy of Prof. Alex. G. McAdie. These
years have the temperatures for the summer
season closely approximating to the average
for 12 vears recorded.
Record for 1902 supplied by courtesy of Prof.
Alex. G. McAdie.
Do.
Fresno Cal
Laghouat, Algeria (extreme
northern Sahara).
Orl6ansville, Algeria .
Tucson Ariz
Biskra, Algeria (northern
Sahara).
Phoenix, Ariz. (Salt River
Valley).
Ayata, Algeria (Oued Rirh,
Sahara) .
Tougourt, Algeria (Oued
Rirh, Sahara).
El Golea, Algeria (interior
of Sahara).
Bagdad
Sal ton, Cal. (Sal ton Basin)..
Salton 1902
Imperial, Cal., 1902 (Salton
Basin).
It is remarkable how nearly alike the sums of the daily maximum
temperatures are for Salton and Imperial for 1902 when we consider
how different the sums of the daily mean temperatures are, (See Table 9,
p. 66). If the records for 1902 are correct at both points it would indi-
cate a noteworthy difference in climate, the maxim urns being propor-
tionally higher at Imperial than at Salton. These sums of temperatures
show that the Deglet Noor date is certain to mature fully at Imperial,
in the heart of the irrigated portion of the Salton Basin; this is indi-
cated not only by the sum of the daily mean temperatures, but still
more clearly by the sums of the daily mean maximum temperatures
during the fruiting season.
It is worthy of note that by this system of calculating the sum of
heat is higher at Phoenix than at Biskra, whereas the order was
reversed when a summation of the mean daily temperature was made
(see Table 9, p. 66). This result leads one to hope that the Deglet
HEAT REQUIRED TO MATURE FRUIT. 69
Noor may after all ripen in the Salt River Valley. By this method of
calculating, as well as by the summation of the mean temperatures,
Salton heads the list, being- the hottest desert station known. a There
can be no question that the Deglet Noor and other choice late sorts
will mature here and in the other parts of the Salton Basin.
The advantages of excessively hot summer climates for date culture
are demonstrated in the Souf country in the Sahara, a region covered
with large dunes, sometimes 500 feet high, of wind-blown sand (PI. II,
p. TO), lying about 50 miles east of the Oued Rirh and probably having
about the same summer climate as Ayata and Tougourt. The best
Deglet Noor dates are said to come from the Souf and are grown in
peculiar sunken gardens excavated to a depth of from 25 to 30 or even
50 feet. These sunken gardens, called "Ghitan" or "Rhitan" (see
tig. s), are dug down to within a few feet of the level of the ground water
*-*
FIG. 8. Sunken date gardens in the sand dunes in the Oued Souf region, near El Souf, Algeria.
and are large enough to contain from to 100 palms, usually from 25
to 50. The sides are sloping, and composed of sand which reflects the
sun's heat and light on the leaves from the sides and from below, thus
intensifying the heat to such a degree that even the Arabs can not
work in these gardens during the hottest weather.* In these torrid
gardens the space is so valuable that the palms are not allowed to pro-
See footnote, p. 66.
&No irrigation is necessary for the date palm in these gardens, as the roota reach
the moist sand near the water level. The chief labor is the carrying out of the sand
blown in by the wind. When the hot simoon winds of summer blow, the natives
do not attempt to work during the day but commence after midnight when the
temperature is lowest. So difficult is the struggle against the sand blown into the
gardens by every high wind that their labor has been likened to that of ants rather
than that of men.
70 THE DATE PALM.
duce offshoots, which are imported f rorn the Oued Rirh country when
needed to plant new gardens. A single palm may be worth from $80 to
$100 arid may produce as much as 330 pounds of dates, which bring the
highest price of any in the Sahara. There can be little doubt that the
superior quality of these dates is due to the accumulation of heat in
the still air of the sunken gardens by reflection from the bare sand of
the sloping sides.
In the Salton Basin the Deglet Noor date can doubtless attain the
same perfection with infinitely less expense and trouble, since the
higher summer temperature will give the same heat in level orchards
that is reached in the sunken gardens of the Souf .
EFFECTS OF WIND ON THE DATE PALM.
In the large deserts there are frequently high winds which are
usually very hot and dry and sometimes so violent as to carry great
quantities of dust and sand. Delicate foliage is injured by such winds
in two ways; first, by being lacerated by the violence of the wind and
also bruised and abraded when sand is carried; second, by the drying
action of the intensely hot, dry air, especially on leaves which have
been torn or injured. Such winds often cause great discomfort and
even grave danger to caravans in the desert. ' ' The spectacle is fright-
ful, the impression most painful, the danger real; sand obscures the
air and singes the face, it fills the eyes, the mouth, the ears; it hurts
the throat and dries up the water skins of the native caravans, which
are thereby in danger of perishing. " a
Such winds, called "simoons" or "siroccos" in the Sahara, often
blow several days in succession, sometimes keeping up all night.
During such winds the relative humidity sometimes falls as low as 2
per cent at a temperature of 33 C., corresponding to 0.75 mm.
pressure of water vapor, J whereas the mean humidity of the driest
month at Paris, for example, is 57 per cent, and at Biskra 25 per cent
(see p. 53).
Observations made by the writer at Biskra during a sirocco at 3
o'clock p. m., May 13, 1900, showed even less humidity. The dry
thermometer read 38.5 C. and the wet bulb sling thermometer
15.3 C., corresponding to a relative humidity of 2 per cent and
an absolute pressure of water vapor of 1.02 mm/ Sometimes the air
is so dry in the interior of the Sahara that the instruments such as
have been used do not indicate the presence of any water vapor
whatever.
a Holland, Georges. Geologic du Sahara algerien, p. 225.
&Massart, Jean. Un voyage botanique au Sahara. In Bui. Soc. Roy., Bot. de
Belgique, vol. 37 (1898), I, p. 273, observations made near Ouargla at, noon, May
23, 1898; the wet-bulb sling thermometer registered 14.2 C., which gives nearly 7
per cent relative humidity by Prof. C. F. Marvin's tables (Weather Bureau Publica-
tion No. 235, 1900).
c Calculated by Prof. C. F. Marvin, Weather Bureau, U. S. Dept. of Agriculture.
EFFECTS OF WIND. 7l
Such winds have no bad influence on the date palm, but on the con-
trary favor the proper maturing of the fruit in regions where the sea-
son is short and some oases in northern latitudes fail to produce a crop
if the hot winds do not blow frequently. a The date trunk is so strong
and elastic and so firmly attached by the cord-like roots that it is an
extremely rare occurrence for a palm to be broken or blown over 1>\
the heaviest gales, although the crown of leaves at the top of the slen-
der stem exposes the trunk to the greatest possible strain. The loaves
are very tough and strong and are very seldom torn by the wind or
bruised by sand. The on\y harm heavy windstorms do is to interfere
with the setting of the fruit by blowing the pollen away. This injury
can usually be remedied by repollination after the storm is over. In
the Salt River Valley, at Tucson, and at many other points in southern
Arizona, the average wind velocity is low and wind storms are infre-
quent, so the date palm has in these regions no particular advantage
over other plants because of its ability to support wind and sand storms.
In the Salton Basin, however, the case is different, as rather heavy
winds are not uncommon, and dust and sand are often carried in consid-
erable amounts. These winds are, however, certainly not so severe as
in the Sahara and will in no way interfere with successful date culture.
It seems, however, that in the great date region about Bassorah, at
the head of the Persian Gulf, the "shamel," or hot wind laden with
dust, may do great damage. Mr. Fairchild states b that ' ' if this (shamel)
occurs before the dates have sufficiently matured it dries them up and
covers them with dust, checking their development and soiling them
so that they are refused by the European and American importers.
Last year's crop (1901) was seriously injured in this way, and the
export was reduced from nearly 2,000,000 cases to about 1,000,000."
It is conceivable that the enormous losses occasioned in the Bassorah
region by hot, dust-laden winds, which are nowhere else reported to
have so deleterious an action, may be due to the peculiar character of
the climate at the head of the Persian Gulf. The proximity of the sea
causes the humidity to be much greater here than in most date-growing
regions, and this unusual humidity may perhaps render the develop-
ing dates peculiarly susceptible to injury by desert winds, possibly by
rendering their surface sticky and thereby causing the dust carried
by the wind to adhere to them.
The cold northwest winds which often blow for several days at a
time during the winter and spring in the Algerian Sahara c and the
At the oasis of Khabis in Persia dates do not ripen well unless the hot, dry, desert
wind blows at least forty days during the summer. Abbot, cited by Fischer, Die
Dattelpalme, p. 55.
&Fairchild, D. G. Persian Gulf Dates and Their Introduction into America.
Bui. 54, Bureau of Plant Industry, U. S. Department of Agriculture, p. 28, 1903.
c Holland, Georges. Hydrologie du Sahara algerien, p. 416.
72 THE DATE PALM.
cold north and east winds in southern Tunis a are said to hinder the
pollination of the date palm. When they occur in summer they retard
the maturing of the fruit and may even cause it to drop. In Seistan, in
the plain of southern Persia, at an altitude of 1,300 feet above the sea
level, in the same latitude and altitude as flourishing date oases in the
Sahara, date culture is entirely prevented and all other fruit cultures
rendered impossible except in the shelter of high walls by the " Badi
sado biat," or "120-day wind,"- a violent, bitterly cold northwest
wind which blows from the spring equinox until about July 20. b This
wind would destroy the flowers of the date palm if they were exposed
to it, and as the date palm can not easily be protected by walls, its
culture is not attempted in this region, though it is followed in oases
lying at higher altitudes far to the north which by their position in the
shelter of mountain ranges are protected from such winds. It is pos-
sible that in spring cold winds may occur in the Salton Basin, but they
are probably less violent than in the Sahara, and are of course not to be
compared to the u badi sado biat" of Seistan.
RESISTANCE OF THE DATE PALM TO ALKALI.
The date palm has long been known to withstand large quantities of
alkali/ and some have even claimed that a certain amount of salt in the
soil is beneficial to its growth. ^ As to how much alkali the date palm
can resist and still grow and bear fruit in profitable quantities practi-
cally nothing definite is on record, notwithstanding the fact that hun-
dreds of thousands of dollars have been invested by the French com-
panies in plantations of date palms in the oases of the Algerian Sahara
where alkali abounds. Apparently the date palm is so enormously
resistant that it has not been necessary to pay much attention to the
amount of alkali in the soil where it is grown. It has been planted on
soil of practically all degrees of alkalinity and irrigated with all sorts
Masselot, Les dattiers des oasis du Djerid. In Bui. Direct, de 1' Agriculture et du
Commerce, Regence de Tunis, vol. 6 (1901), No. 19, p. 121.
& Bellew, H. W. From the Indus to the Tigris, London, 1874, p. 239.
c The term alkali is applied rather loosely to the more readily soluble saline matters
which accumulate in the soils or in the water of desert regions. In spite of the name
such salts are mostly neutral in reaction, consisting chiefly of chlorids, sulphates,
and nitrates of the bases sodium, potassium, and magnesium. Only the carbonates
of sodium and potassium, constituting the much-dreaded " black alkali," are strongly
alkaline in reaction, and because of their caustic nature much more deleterious to
most plants than are the neutral salts or "white alkali," which latter are injurious
chiefly indirectly by rendering the soil water too concentrated a solution and thereby
unfitted to nourish the roots.
^ Ibn-el-Fasel, an" Andalusian Moor, whose book, written in the twelfth century,
unfortunately has been lost, is said to have given the exact amounts of salt which
should be mixed with the manure for date palms. (See Cusa, Salvatore, in Archive
storico siciliano, I, 1873, p. 356. )
RKSISTANCK TO ALKALI. 73
of water, from good drinking water to veritable brine containing 1
per cent of saline matters. It is the custom to provide for drainage,
usually by means of open ditches, in the oases having much alkali in
the soil or in the water. If the drainage is good, abundant irrigation
has the effect of washing the excess of alkali out of the soil. . However,
even in such situations there has been little study of the best means of
preventing the accumulation of alkali or of washing it out of the soil,
and many of the planters have no comprehension of its action on the
date palm.
INVESTIGATION OF THE ALKALI-RESISTING POWER OF THE DATE PALM
IN THE SAHARA.
In view of the entire absence of trustworthy data as to the alkali
resistance of the date palm, the writer determined on the occasion of
his last visit to the Sahara Desert in 1900 to make a study of the soils
in the date plantations in order to determine the amount of alkali these
soils contain and what effect it had on the growth and fruiting of the
date palm when present in excessive quantities. Samples of soils were
secured in five different regions in the Algerian Sahara (see map, PI.
II, p. 76), representing several different methods of culture and drain-
age and showing all degrees of alkalinity. Through the kindness of
Prof. Milton Whitney, Chief of the Bureau (then Division) of Soils of
the Department of Agriculture, who also furnished instruments for
collecting and studying the soils on the spot, these samples were ana-
lyzed by Mr. Atherton Seidell in accordance with the methods usually
followed in the Bureau of Soils, namely, by digesting 50 grams of soil
in a liter of water for twenty-four hours and then analyzing the super-
natant solution. The analyses made in this manner do not represent
accurately the conditions existing in the soil water, since the amount
of the slightly soluble salts, especially gypsum, reported is far in excess
of what could dissolve in the soil moisture, which in the rather sandy
loam of most of the Sahanin oases would constitute about 8 to 15 per
cent of the weight of the soil, whereas in the method followed in mak-
ing the analyses about 150 to 200 times as much water was used. In
this bulletin, therefore, the analyses of Mr. Seidell have been recalcu-
lated in order to represent more nearly the conditions existing in the
soil. The amount of calcium sulphate' thai goes into solution in the
soil moisture has been estimated at 0.05 per cent in all the analyses,
except where large amounts of other sulphates were in solution, when
it was estimated at 0.02 percent. The amount that dissolves undoubt-
edly varies somewhat, depending on the quantity and nature of the
other salts present in solution. However, the amount here e>timat-d
is not far from the quantity actually present, and its inclusion in the
analyses renders them much more useful than to omit the gypsum
74 THE DATE PALM.
altogether, or to include the very much larger amounts reported in the
original analyses. 01
The solubility of gypsum in the soil moisture is difficult to estimate,
especially in the presence of large amounts of other salts in varying
proportions^ The researches of Doctor Cameron and Mr. Seidell, 6 of
the Bureau of Soils, show that in pure water at 25 C. the solubility of
calcium sulphate is about 0.21 per cent, or 2.1 grams of calcium sulphate
per liter of water, which would equal 0.27 per cent of gypsum. In a
1 per cent solution of common salt 0.44 per cent of gypsum is dissolved,
and in a 4.9 per cent salt solution 0.75 per cent of gypsum. In mag-
nesium chloride an even greater solubility was observed and in a 10.5
per cent solution of this salt 11.13 per cent of gypsum dissolves. On
the other hand, salts which yield either calcium or sulphuric acid ions
on solution decrease the solubility of gypsum. In a 1.54 per cent solu-
tion of sodium sulphate only 0. 16 per cent of gypsum is dissolved, though
in a stronger solution more is taken up until, in a 22.2 per cent solu-
tion of sodium sulphate, 0.26 per cent of gypsum is dissolved. Calcium
chlorid in solution depresses even more the solvent power of water
for gypsum.
Estimating the water content of the Saharan soil, mostly sandy loam,
at 10 per cent on the average, and the solubility of calcium sulphate at
0.5 per cent (equal to 0.6 per cent of gypsum) on the average in the
salts such as occur in the Fougala and Oued Rirh region of the Sahara,
the amount of calcium sulphate to be counted as alkali would be 0.05
per cent of the weight of the soil. When there -were large amounts
of sodium sulphate present, as at Chegga, the amounts of calcium
sulphate would be much less, probably about 0.02 per cent (equal to
0.025 per cent of gypsum) of the weight of the soil. c
This method of expressing the amount of alkali is the one most
easily applied where the analyses are made by extracting the alkali
with an excess of water, but it is very doubtful whether it gives a cor-
a In most alkaline soils the presence of gypsum is advantageous by preventing the
formation of the very harmful carbonates of sodium and potassium (see pp. 101 and
119) by neutralizing the poisonous effect of the salts of magnesium (see p. 89).
The physical action of alkali in rendering the soil water too concentrated to support
the roots of plants is, however, exerted as much by gypsum as by any other salt in
solution in equal amounts.
& Cameron, Dr. Frank, and Seidell, Atherton. Bui. No. 18, Bureau of Soils, U. S.
Department of Agriculture, pp. 39, 40, and 46-57.
c Mr. Seidell's original analyses are given in every case as a footnote in order to
facilitate any comparisons which students of alkali conditions may desire to make
with analyses reported in other ways than has been done by the writer. As a result
of this slight emendation the analyses are brought into such shape that the results
may be compared, without danger of serious error, with the determinations of alkali
made by the electrical method, on which data all the newest and best maps of the
alkali lands of the Southwest which have been issued by the Bureau of Soils have
been prepared.
EESISTANCE TO ALKALI. 75
rect idea of the alkali condition of the soil in relation to crop produc-
tion, since the most important factor in reference to plant growth is
the degree of concentration of the soil moisture. Inasmuch as the
water capacity varies greatty in different types of soils it is easily
possible that ,two soils having the same percentage of alkali by weight
may differ very greatly in their ability to support crop plants sensitive
to alkali. Thus in a coarse sandy soil having a low water content the*
concentration of the soil moisture may be three or four times as great
as in a heavy clay soil having a correspondingly greater water capacity.
Fortunately it is now possible to determine quickly and accurately
the degree of concentration of the soil moisture with tho ingenious
instrument devised by Professor Whitney and Mr. Briggs, by meas-
uring the electrical conductivity of a column of soil saturated with
water. a While this method shows approximately the degree of con-
centration of the soil water to which the roots of plants would be
exposed, it gives no indication as to the composition of the alkali,
which often varies greatly in soils only a few rods apart. Inasmuch
as different sorts of alkali vary greatly in their poisonous action on
the roots of plants, the needs of the biologist and agriculturist would
be served best by the employment of both methods, the electrical giv-
ing the concentration of the soil water; the analytical, its chemical
composition. At the same time a physical analysis of the soil show-
ing the water capacity would be useful in forecasting the danger of an
increase in alkali content through the evaporation of saline irrigation
water or by a rise of alkali from the subsoil.
The soils secured from the Sahara, with the exception of the one
above mentioned from Biskra, were all similar in nature, being com-
posed of sandy loam or fine sand. In consequence the results of the
anatyses reported in this bulletin are fairly comparable one with
another and are not likely to lead to an overestimate of the alkali-
resisting power of the date palm, since the water capacit}^ of these
soils is low, and as a result of this the concentration of the soil water
is high in proportion to the percentage of alkali present in the soil.
The limits of alkali resistance worked out in this bulletin are then
directly applicable to the soils best adapted to date culture, viz, sandy
loams, and for all other heavier soils are below rather than above the
true limit/'
a This method depends upon the degree of ionic dissociation, rather than the total
content of dissolved substance, and gives the best physical measure of the relative
concentration and toxicity of solutions of similar composition.
& Very coarse sand would- have a lower water capacity than the Saharan soils here
studied, but alkali leaches out of coarse sand very easily, so that in such soil a dan-
gerous accumulation of alkali is not common, though if present the limits here
determined for the alkali resistance of the date palm would be too high because of
the excessive concentration of the soil water in proportion to the percentage of alkali
present.
76
THE DATE PALM.
The very unusual ability of the date palm to withstand alkali is of
the utmost importance, since it permits it to be grown profitably in
soils unfit for any other paying crop and where ordinary vegetation
can not grow at all. The date palm is also of great value in aiding in
the reclamation of alkaline lands; for once planted to dates and reg-
ularly irrigated the soil improves by a washing out of the alkali if the
irrigation water is of good quality and if drainage facilities exist. The
importance of the alkali-resisting power of this plant is so great that
the results of the examination into the alkali conditions in the Algerian
Sahara are given in detail, as they constitute the most trustworthy
evidence so far in existence as to the amount of alkali the date palm
can stand without injury.
ALKALI CONDITIONS IN RELATION TO DATE CULTURE AT BISKRA, ALGERIA.
The first important oasis planted to date palms seen in entering the Sahara by
the railway is at El Kantara (see map, PI. II), where a narrow gorge separates the
Algerian high plateau from the Sahara, and in a few moments the train passes from one
region to the other. At El Kantara, however, the date palm is chiefly valuable in
furnishing a shelter and partial shade to other fruit trees, and it is at Biskra that the
date palm is first seen under conditions permitting its best growth. This oasis con-
tained some 95,000 palms in 1882, and now has a total of about 100,000 bearing
date palms. The two near-by oases of Filiache and Chetma contain 35,000 more.
Biskra is situated in a plain near the west bank of the Biskra River. The irrigation
water is furnished by large springs, situated in the bed of the river, which yield
about 13,000 liters, or 3,434 gallons, per minute. This water has been analyzed fre^
quently, with fairly concordant results, the content of dissolved salts being given
as follows by various chemists: Vatonne, 0.216 per cent; Buvry, 0.2236 per cent;
Lahache, 0.226 per cent; Moissonnier, 0.2346 per cent.
The detailed analyses by Moissonnier and Buvry are as follows:
TABLE 11. Composition (in percentage, by weight] of spring water used for irrigating
the oasis of Biskra, Algeria.
Authority.
Cal-
cium
carbon-
ate.
Magne-
sium
carbon-
ate.
Cal-
cium
sul-
phate.
Magne-
sium
sul-
phate.
Sodium
sul-
phate.
Magne-
sium
chlo-
rid.
Sodium
chlo-
rid.~
Silica.
Total.
Moissonnier 1
0. 0278
0156
0.0070
0.0621
.0448
0.0357
0. 0102
.0474
0.0894
.0878
0.0024
0.2346
.2236
Buvry 2
0. 0280
1 Moissonnier, Recueil de mem. de medicine mil., 3 ser., vol. 31, pp. 260-267.
2 Buvry, Zeitschrft. f. allgem. Erdkunde, N. F., vol. 4, p. 200. Vide Fischer, Die Dattelpalme, p. 41.
In winter, when there is a flow of water in the Biskra River, the water in the irri-
gating canals may contain as low as 0.075 per cent of dissolved salts, largely gypsum
(0.0437 per cent), according to Moissonnier.
The very good quality of the water in winter, together with the shortage of water
in summer there being only 0.1 liter per tree per minute when 0.3 is needed (see
p. 45) favors the practice of winter and spring irrigation commonly followed in this
An analysis of the river water mixed with the spring water after a rainstorm in
April, 1880, as reported by Holland, showed only 0.04 per cent of salts, nearly half
calcium carbonate (0.01852 per cent).
Bui. 53, Bureau of Plant Industry, U. S Dept. of Agriculture.
PLATE II.
f KILOMETERS
PORTION OF THE SAHARA DESERT IN SOUTHERN ALGERIA, SHOWING PRINCIPAL
CENTERS OF DATE CULTURE.
ALKALI CONDITIONS AT BISKRA.
77
oasis, either indirectly by growing crops needing abundant irrigation between the
palms, or directly in soaking the ground about the trees. It is doubtless because of
the very low alkali content of the irrigation water in winter and the only moderate
content in summer that the alkali is not troublesome in this oasis, although surface
flooding is never practiced, water being applied in excavations called "dahir," hold-
ing a barrel or more (PI. XVII), which are made about the base of the tree (see
p. -17). Biskra has clay soils of great depth (as much as 40 feet) and this doubt-
less constitutes an additional reason for irrigating by means of dahir, since such
soils are difficultly permeable for water and have a great water capacity, so that if
irrigation were practiced by flooding the whole surface the water would largely be
evaporated or absorbed by the surface layers of the soil, and only a small proportion
would ever percolate to the roots of the date palm, especially in summer, when the
supply of water is scanty.
Station No. 1, where soil samples were secured, was in a garden belonging to the
Victoria Hotel, some 25 feet away froni a century-old date palin (see PI. XIII), and
near a vigorous young Deglet Noor palm (see fig. 1, p. 16). Alfalfa and burr clover
(Mfdicago denticidata) were growing where the sample was obtained. The subsoil
was a stiff c]ay.
The percentage of the weight of the soil soluble in 20 times its weight of water was
0.42 for the surface foot and 0.40 for the subsoil. The following salts were found by
Mr. Seidell:
TABLE 12. Amount and nature of salts soluble in excess of water in soil from date garden
at Biskra (expressed in percentages of the total weight of the soil) - 1
Depth.
Calcium
bicarbon-
ate.
Magnesium
bicarbon-
ate.
Calcium
sulphate.
Sodium
chlorid.
Potassium
chlorid.
Total.
Surface foot
0.19
0.05
0.10
04
0.04
42
Subsoil (24 to 30 inches )
15
06
11
04
04
'40
'TMs table is identical with Mr. Seidell's original analysis.
Disregarding the very slightly soluble calcium carbonate, the following would rep-
resent approximately the alkali content of the soil water:
TABLE 13. Per cent of alkali in soil of palm garden at Biskra, Algeria.
Depth.
Calcium
sulphate.
Sodium
chlorid.
Potassium
chlorid.
Magnesium
bicarbon-
ate.
Total.
Surface foot .-.
0.5
0.04
0.04
0.05
0.18
Subsoil (12 to 14 inches)
5
.04
.04
.06
.19
The amount of alkali present in this soil is insignificant and in no way affected the
growth of alfalfa. This sample is also interesting as being a heavy clay soil of the
sort which largely composes the oasis of Biskra, but which does not occur in the
other oases studied. Such soils are not considered as favorable for date culture
as loamy or sandy loam soils; nevertheless date palms grow very well at Biskra,
although the late sorts do not ripen their fruits properly because the summer and
autumn are not hot enough.
Of the area surveyed by Messrs. Holmes and Means, of the Bureau of Soils, in the
Salton Basin, California, 23,120 acres, or 30 per cent, is a heavy clay comparable to
this sample, and half this area contains less alkali than the Biskra garden, and a
quarter more contains only slightly greater quantities (0.4 to 0.6 per cent), where
Such soils are common in the Salton Basin in California. (See PI. Ill, pp. 106
and 108.)
78 THE DATE PALM.
the date palm would be able to grow as well as in the Sahara oasis, since the irrigat-
ing water here is of better quality than at Biskra."
ALKALI CONDITIONS IN RELATION TO DATE CULTURE AT FOUGALA, ALGERIA.
In proceeding west from Biskra one traverses the so-called Western Zab, & which
is first seen beyond a low mountain range, the Djebel Mendjenaib, adjoining Biskra
on the west. The Western Zab, or more accurately, the Zab Dahri (Map, PI. II,
p. 76, and PL XV), is a flat plain, 120 to 172 meters above sea level, which
slopes gently to the south or southeast. To the north the plain is limited by the
foothills of the Atlas Mountains, which rise rather abruptly. Throughout the
Western Zab, at least along the route followed between Biskra and Fougala (see map,
PL II), there are practically no surface indications of water, the vegetation being
very scanty, consisting mostly of the "Zeita" bush (Limoniastrum guyonianum),
which usually indicates the presence of much gypsum in the soil where it grows
(see Yearbook 1900, PL LIX, fig. 5). In extremely alkaline spots where chlorids
predominate the Zeita disappears, and is replaced by saltbushes (Atriplex), sam-
phires (Salicornia), etc.
There occur throughout the Western Zab occasional large springs which are used
to irrigate many oases situated at a somewhat lower level to the southward. Begin-
ning at Farfar there is seen a most characteristic and most curious system of date
culture. The young date offshoots are planted at the bottom of pits about six
feet square, and from 4 to 8 feet deep (PL XV, fig 1). An inspection of a freshly
made ditch, or "bir," as it is called by the Arabs, shows that the ditch is just deep
enough to penetrate an impervious hardpan, composed of marl and gypsum. Below
this stratum water is found and the palms are so planted that their roots can easily
penetrate to the water level, and after once getting established they are able to grow
without being irrigated from the surface. As the palms grow older the ditches are
slowly filled up, the palms in the meantime sprouting forth roots all along the lower
part of the trunk. In some cases very old trees are seen to be banked up instead of
being planted in ditches (PL XIV, fig. 1). Curiously enough the trees planted in
such pits are often irrigated, although their roots are in contact with water. As will
be shown later on, this is doubtless done in order to aerate the subsoil and to wash
out the alkali, which would otherwise be left at the surface by the evaporation of
the moisture brought to the surface by capillary attraction. When irrigated, there
is of course perfect drainage through the bottom of the "bir" to a practically fixed
water level below.
At Fougala a French company purchased an entire oasis containing thousands of
old bearing date palms, and has made in addition extensive new plantations. This
property comprised in 1900 some 263 hectares and contained about 18,000 bearing
date palms and 6,000 young trees not yet in bearing. On this property irrigation
has been practiced on an extensive scale, although the older palms were grown by
planting in pits as previously described, and were irrigated when young by the Arabic
method, namely, by raising water from shallow wells by means of buckets attached
to sweeps ( ' ' kitara " ) c (PL XIV, fig. 2) . The wells on this property are from 9 to 12
feet deep and are from 6 to 8 feet square. They yield about 35 gallons per minute,
for some three hours, by which time the water is usually exhausted. These sweeps
are run at this rate by a single Arab, although on some wells there are double sweeps,
and then two Arabs work side by side. The water from such wells is poured into
a large receptacle called "jabia," from which it flows into irrigation ditches. In
o Biskra water contains from 0.075 to 0.235 per cent of alkali and is worst in sum-
mer. (See p. 76. ) Colorado Kiver water used to irrigate the Salton Basin contains
from about 0.021 to 0.125 percent of salts and is best in quality in midsummer, when
the flood occurs.
& Marked Zibane in the map, PL II, p. 76.
c See also Yearbook 1900, PL LXI, fig. 6.
ALKALI CONDITIONS AT FOUGALA. 79
addition to these native wells the Companie de 1'Oucd Rirh has put down several arte-
sian wells which are some 80 meters deep and yield from 50 to 75 gallons of flowing
water per minute, which is conducted directly into the irrigation ditches. This water
is remarkably pure, containing very much less salts in solution than the artesian water
of the Oued Rirh country or that of Biskra. A rough test of its electrical conductivity
indicated the presence of about 0.085 per cent of dissolved salts.
The effect of irrigation with this water is marvelous. Old date palms which had
made a slow and stunted growth and which had fruited but little, at once grew
luxuriantly when irrigated and began to bear heavy crops of fruit. Inasmuch as
these trees had their roots in constantly moist layers of earth, the effect of irrigation
was in all probability due not so much to the increased supply of water as to other
actions brought about by irrigation. In the first place, the structure of the soil and
the manner in which the date palms are planted in pits which penetrate the hard-
pan, below which standing water occurs, hinder the aeration of the subsoil and at
the same time favor the accumulation at the surface of the alkali dissolved by the
capillary currents of water in ascending through the strongly alkaline soil. On the
other hand, irrigation with the remarkably pure water furnished by the deep arte-
sian wells would tend to have exactly the opposite effect, namely, the subsoil would
be aerated by means of the water which had been flowing in surface ditches, and
secondly, the watering of the date palms with an abundant supply of pure water,
coupled with a perfect system of drainage by means of the holes through the imper-
vious subsoil & over which the trees are planted, would bring about the washing out
of the alkali from the soil, especially where the trees were irrigated frequently and
with large amounts of water. The hardpan would tend to confine the alkali and
prevent its rise between the trees after it was once washed out of the soil.
Although the date palm can grow, as will be shown further on, in soils containing
as high as 3 per cent of alkali, even when irrigated with strongly brackish water con-
taining over 0.6 per cent of salts in solution it being in fact able to endure more
alkali than any other plant cultivated in the Sahara Desert there can nevertheless
be no doubt that its growth is retarded and its fruitfulness lessened by the presence
of large amounts of alkali in the soil or in the irrigation water. It was noticeable at
Fougala that the trees which were grown in the most alkaline parts of the oasis, and
especially where surface irrigation with pure water had not been practiced, were
stunted and show r ed a pronounced yellowish color of the leaf and especially of the
leafstalk. This was later seen in the oases in the Oued Kirh country, and it would
seem to be an indication of an excess of alkali beyond the amount which the trees can
endure without noticeable injury.
An effect of pure water similar to that observed at Fougala has been noticed at
Koseir, in the Egypto-Arabian desert, on the shores of the Red Sea, w r here Klunzinger
reports c that dwarfed date palms 30 to 40 feet high grow on the very alkaline soil
and were nourished by very brackish water, but yield crops of small but very sweet
dates only in good years after heavy rains. The action of these heavy rains probably
would be much like that of the irrigation with the pure artesian water at Fougala.
The natural springs in the Western Zab, according to Rolland (Hydrologie du
Sahara) , are supplied from the same source that feed, 1 the artesian wells, viz, the
water carried in the cretaceous strata which are upturned in the Aures Mountains
limiting the Sahara on the north and which underlie the whole northern belt of the
Sahara. The water of these springs soaking into the soil feeds the superficial layer
of water which directly underlies the hardpan at Fougala. Very probably this
hardpan has been formed by the action of this standing water.
& Professor Hilgard has noted the drainage through holes in the hardpan in the
San Joaquin Valley in California. Bui. No. 83, California Experiment Station.
c Klunzinger, C. B. Die Vegetation der egyptisch-arabischen Wiiste bei Koseir,
in Zeitschrift d, Gesellschaft f. Erdkunde, Berlin, vol. 13 (1878), pp. 432-462.
80
THE DATE PALM.
It is difficult to say how much of the beneficial effect observed in Fougala from
surface irrigation is due to the better aeration of the subsoil thereby brought about.
There can, however, be little doubt that the date palm is distinctly favored by a
proper aeration of the soil in which it grows, since the palms at Fougala when irri-
gated from the shallow wells did better than those nearby which have their roots in
contact with the very same layer of water which fills these wells. Of course the
identity of the water supply in the case in question does not exclude the probability
of the alkali being washed out from the surface soil by abundant irrigation, even if
the water used is rather brackish. Unfortunately no tests were made of the water
in these surface wells, but it is undoubtedly much more alkaline than the water of the
deep artesian wells. Other observations made at Ourlana in the Oued Eirh region
went far to show that proper aeration of the subsoil is even more important than
absence of alkali for the proper growth and fruiting of the date palm. For instance,
the extremely brackish water which, flows from the drainage ditches is nevertheless
used in some instances to irrigate palms planted at lower levels and without apparent
injury, although such palms do not show a rapid growth (see p. 98).
Station No. 1 at Fougala represents the undisturbed desert conditions (PI. XV,
fig. 1). It was situated where no culture, drainage, or irrigation had been practiced,
or at least not in modern times/' The samples were taken a short distance to the
northeast of the ruins of an old Roman fort. The natural vegetation consisted of
a scanty growth of saltbushes, samphires, and other plants able to stand much alkali.
A date palm, yellow and evidently not in a thriving condition, was growing near by.
The amount of alkali present in the surface crust and at various depths is shown
in the following table:
TABLE 14. Per cent of alkali in undisturbed Saharan soil at Station No. 1, Fougala,
Algeria. 1
Depth.
Calcium
sulphate.
Magnesi-
um sul-
phate.
Sodium
sulphate.
Sodium
chlorid.
Potassi-
um chlo-
rid.
Magnesi-
um chlo-
rid.
Sodium
bicarbon-
ate.
Total.
Surface crust
07
41
1 44
9 19
53
12
11.76
Surface soil (1 to 12
inches) .
05
34
37
3 79
.29
.08
4.92
Subsoil ( 12 to 30 inches)
.05
.23
1.32
.12
0.02
.08
1.82
Subsoil (30to48inches
estimated )
. (.05)
(.17)
(.98)
(.10)
(.02)
(.08)
(1.40)
Soil (1 to 4 feet esti-
mated ) .
(0.38)
(1.98)
(.08)
(2.44)
1 Mr. Seidell's original analyses of the samples from this station are as follows:
Composition.
Crust.
Soil, 0-12 inches.
Subsoil, 12-30
inches.
Alkali in
soil.
Composi-
tion of
alkali.
Alkali in
soil.
Composi-
tion of
alkali.
Alkali in
soil.
Composi-
tion of
alkali.
Ca...
Per cent.
1.65
.08
4.12
.28
5.26
5.82
.09
Per cent.
9.53
.48
23.81
1.60
30. 42
33.64
.52
Per cent.
1.39
.07
1.64
.15
3.86
2.44
.06
Per cent.
14.51
.70
17.02
1.62
40.16
25.37
.62
Percent.
1.28
.05
.54
.06
3.26
.88
.06
Per cent.
20.89
.85
8.83
1.01
53. 10
14.34
.98
Mg
Na....
K
SO 4 ...
Cl.
HCO 3
Total..
17.30
100.00
9.62
100.00
6.13
100.00
CaSO 4 . . .
5.61
.41
.53
9.19
1.44
.12
32.38
2.41
3.08
53.06
8.35
.72
4.74
.34
.29
3.79
.37
.08
49.28
3.49
3.07
39.47
3.84
.85
4.36
.23
.12
1.32
70.98
3.75
1.95
21.60
MgSOi
KC1...
NaCl .
NuSO 4
NaHCO
.08
.02
1.33
.39
MgCl 2
Total
17.30
100. 00
9.61
100.00
6.13
100.00
Similar conditions near this station are shown in Yearbook, 1900, PL LXI, fig. 4,
in the background.
ALKALI CONDITIONS AT FOUGALA
81
It will be noted that the most readily soluble salts, sodium sulphate and the
chlorides, are largely concentrated in the surface soil. This is shown graphically in
the accompanying diagram (fig. 9), in which the curves are smoothed so as to show
approximately the distribution at various depths of the more important salts com-
posing the alkali at this station.
This distribution of alkali is the common one when there is an appreciable rain-
fall, as in the northern Sahara (about 9 inches at Biskra), but is very unlike that of
the nearly rainless Salton Basin, where the subsoil often contains more alkali than
the surface layers.
This soil was excessively alkaline, the surface foot containing nearly one-twentieth
of its weight of alkali, and the whole surface soil to a depth of 4 feet containing nearly
2.5 per cent of alkali. Thealkali is characterized by the large proportion of chlorides
(amounting to 81 per cent of the total salts), of which almost all is common salt,
which alone makes up nearly 4 per cent of the weight of the surface foot, or some
160,000 pounds per acre in the surface foot!
Depth
SURFACE
CRUST.
4IN.
8IN.
IFOOT
IblN.
20IN.
2FEET
28IN.
p e
T<
rC
ent <
^ ;
3f A
Ika
iin
' ^-*
tot
\^ 1
aJM
hoJLi
^
~~-
Tto1
.
: So
il.
2
..''
/
^
*>,>
&L
/
c
r>
2
GO
1
/
1
A'
/
/
1
4
32IN.
3 FEET
40IN.
44IN.
AUctu
icor
tent
estirt
tatec
Ifor*
dept
rbel
ow3
Otn.
Common, S 'alt: fSodium, Chlorid )
Magnesium, Svdphate
Glcuuber* SaJbL-(So(luum, Svuiphate)
FIG. 9. Curves showing distribution of alkali to a depth of 4 feet in uncultivated Saharan soil at
Station No. 1, Fougala, Algeria.
This soil is very interesting as representing practically the extreme limit of endur-
ance of the date palm for this type of alkali. Unfortunately samples were not
obtained down to the hardpan, but if the decrease followed the same ratio as in the
Station No. 2, the amount of alkali in the subsoil at 30 to 48 inches would be about
1.42 per cent, and the average for the soil to a depth of 4 feet, 2.55 percent.
Station No. 2, where the soil was sampled at Fougala, was only a few hundred
feet from Station No. 1, in a young date plantation, where irrigation had been prac-
ticed for three years. The samples were taken by cutting away a foot or so of the
side of the pit, or " bir," in which a date palm had been planted three years before.
Fresh earth was reached before the sample was taken. Hardpan was encountered
at a depth of 4 feet. The appearance of the locality is shown in the background of
Plate XV, figure 2.
13529 No. 5304 6
82 THE DATE PALM.
The following amounts of alkali were found:
TABLE 15. Per cent of alkali in soil of young date plantation, station No. 2, Fougala,
Algeria. 1
Depth.
Calcium
sulphate .
Magne-
sium
sulphate.
Sodium
sul-
phate.
Sodium
chlorid.
Potas-
sium
chlorid.
Magne-
sium
chlorid.
Sodium
bicar-
bonate.
Total.
Surface foot . .
0.05
0.25
0.04
1 38
18
08
1 98
Subsoil (12 to 30 inches) . .
.05
.15
.09
.09
0.05
.08
51
Subsoil (30 to 48 inches) . .
.05
.07
06
.07
04
09
38
Hardpan (48 to 54 inches)
.05
.04
.04
.06
.04
.08
31
Soil 1 to 4 feet
.21
.54
08
83
1 Mr. Seidell's original analyses of the samples from this station are as follows:
Soil, to 12 inches.
Subsoil, 12 to 30
inches.
Subsoil, 30 to 48
inches.
Com pact gypsum
subsoil, 48 to 54
inches.
Alkali
in soil.
Compo-
sition of
alkali.
Alkali
in soil.
Compo-
sition of
alkali.
Alkali
in soil.
Compo-
sition of
alkali.
Alkali
in soil.
Compo-
sition of
alkali.
Ca
Per cent.
1.30
.05
.58
.09
3.35
.92
.06
Per cent.
20.46
.79
9.14
1.47
52.70
14.50
.94
Per cent.
1.23
.04
.06
.05
3.07
.14
.06
Per cent.
26.50
.94
1.24
.99
66.03
3.01
1.29
Per cent.
1.18
.02
.05
.03
2.90
.10
.06
Per cent.
27.19
.55
1.10
.83
66.56
2.25
1.52
Per cent.
1.08
.02
.02
.03
2.63
.06
.06
Per cent.
27. 70
.46
.51
.87
67.28
1.64
1.54
Mg
Na
K
SO 4
Cl
HCO 3
Total
6.35
100.00
4.65
100.00
4.34
100.00
3.90
100.00
CaSO 4
4.42
.25
.18
1.38
.04
.08
69.56
3.90
2.83
21.70
.72
1.29
4.19
.15
.09
.09
89.99
3.18
1.89
2.02
4.02
.07
.07
.06
92.37
1.70
1.56
1.43
3.68
.04
.06
94.08
1.02
1.64
MgSO 4 . .
KCL
NaCL
NaoSOi
NaHCO 3
.08
.05
1.76
1.16
.09
.04
2.07
.87
.08
.04
2.09
1.17
MgCL
Total
6.35
100.00
4.65
100.00
4.35
100.00
3.90
100.00
The results of three years' irrigation with pure artesian water is very striking. The
surface crust has disappeared entirely and the amount of alkali has greatly decreased
at all depths.
Station No. 3 at Fougala was situated in the space between large date palms, which
were in a most thriving condition as a result of eleven years' irrigation. Garden
vegetables and cereals had been grown on the land for a number of years. The
hardpan layer was reached at a depth of only 26 inches.
ALKALI CONDITIONS AT FOUGALA.
83
TABLE 16. Per cent of alkali in soil in old date plantation, station No. 3, Fougala,
Algeria. 1
Depth.
Calcium
sulphate.
Magne-
sium sul-
phate.
Sodium
chlorid.
Potas-
sium
chlorid.
Magne-
sium
chlorid.
Sodium
bicar-
bonate.
Magne-
sium bi-
carbon-
ate.
Total.
Surt'iuv foot
0.05
0.06
0.05
0.02
0.01
0.09
28
<ulxoil 12 26
.05
.12
.06
.05
.10
38
Hardpan 26-28
05
04
.03
.04
03
05
24
Soil 1-4 (estimated).
(-1
2)
(.08)
((
)
(.29)
1 Mr. Seidell's original analyses of the samples from this station are as follows:
1
Soil, to 12 inches.
Subsoil, 12 to 26
inches.
Compact gypsum
subsoil, 20 to 28
inches.
Alkali in
soil.
Compo-
sition of
alkali.
Alkali in
soil.
Compo-
sition of
alkali.
Alkali in
soil.
Compo-
sition of
alkali.
Ca.
Per cent.
0.31
.01
.04
.01
.78
.05
.06
Per cent.
24.05
1.26
3.30
.94
61.33
3.93
5.19
Per cent.
1.10
.03
.03
.03-
2.74
.06
.08
Per cent.
27.03
.88
.69
.73
67.19
1.57
1. 91
Per cent.
1.12
.03
.01
.01
2.73
.04
.06
Per cent.
28.03
.70
.25
.40
67.94
1.04
1.64
Mg...
Na
K
SO*
Cl
HCO a
Total
1.26
100.00
4.07
100.00
4.00
100.00
CaSO 4 . . .
1.04
.06
.02
.05
.09
.01
81.76
4.56
1.73
3.77
7.08
1.10
3.74
.12
.06
91.82
2.98
1.37
3.81
.04
.03
95.21
.95
.75
MgSO 4
KC1
NaCl
NaHCO-,
.10
.05
2.60
1.23
.03
.04
.05
.90
.95
1.24
MgCl 2
MgHCOg
Total.
1.27
100.00
4.07
100.00
4.00
10.000
The results of long-continued irrigation with pure water and of good drainage
through the holes in the hard pan are clearly shown in the very much lower percent-
ages of alkali than at stations 1 and 2. The most remarkable feature of this soil is the
almost complete absence of common salt, so abundant at the other two stations at
Fougala, where indeed it constituted the bulk of the alkali. The analyses of the
soils from these three stations represent three stages in the reclamation of very
alkaline desert land and are very instructive. The conditions somewhat resemble
those in the Salton Basin, California, where the irrigation water is also very pure
and where likewise the alkali is largely composed of chlorides. In the latter region,
however, there is no hard pan through which holes for drainage can be dug and which
would serve to keep the alkali down when once it was washed out of the soil. Where
good drainage can be provided the soils in the Salton Basin doubtless can be as
completely freed from harmful excess of alkali as those of Fougala have been.
Station No. 4 at Fougala was situated in a very alkaline spot too alkaline to grow
any crops near a date palm which was yellow and stunted, but which had never-
theless managed to live twenty years or more. Only the surface crust was secured;
it showed the following percentages of alkali salts soluble in an excess (20 times the
weight of the soil sample) of water. The surface crust from station No. 1 is also
given, analyzed in the same way.
84
THE DATE PALM.
TABLE 17. Per cent of alkali soluble in excess of water in surface crusts from Fougala,
Algeria.
Station.
Calcium
sulphate.
Magnesium
sulphate.
Sodium
sulphate.
Sodium
chlorid.
Potassium
chlorid.
Sodium bi-
carbonate.
Total.
Surface crust, sta-
tion No 4 1
3.81
0.84
5.52
4.32
0.40
0.15
15.04
Surface crust, sta-
tion No 1
5.61
.41
1.44
9.19
.53
.12
17.30
1 Mr. Seidell's original analysis of this surface crust is as follows:
Surface soil.
Surface soil.
Alkali in
soil.
Composi-
tion of
alkali.
Alkali in
soil.
Composi-
tion of
alkali.
Ca
Per cent.
1.12
.17
3.53
.21
7.08
2.81
.12
Per cent.
7.44
1.13
23.51
1.41
47.10
18.71
.70
CaS0 4 ...
Per cent.
3.81
.84
.40
4.32
5.52
.15
Per cent.
25.26
5.60
2.69
28.77
36.71
.97
Mo 1
MgSO 4 . .
Na
Kr"i
J
NaCl
SO
NaoSCv
Cl
NaHCOg
HCO,j
Total
Total
15.04
100.00
15.04
100.00
The crust from Station No. 4 shows less than half as much common salt (sodium
chlorid), but four times as much Glauber's salt (sodium sulphate) as that from
station No. 1.
ALKALI CONDITIONS IN RELATION TO DATE CULTURE AT CHEGGA, ALGERIA.
In traveling southward from Biskra one follows near the course of the Biskra Kiver,
and passes occasional areas covered with bushes and small trees, which doubtless
get scanty supplies of water by seepage from the subterranean flow in the river.
After crossing the Oued Djedi (see map, PI. II, p. 76), which is the principal artery of
surface drainage of the Algerian Sahara, but which is usually entirely dry, the Small
Desert of Morran is entered, a region almost entirely devoid of vegetation. At about
30 miles south of Biskra the "bordj " of Chegga (see map, PI. II, p. 76) is reached.
Chegga is about 22 meters (72 feet) above sea level, and is only about 8 miles from
the Chott Melrirh, a salt lagoon nearly dry, which is here some 90 feet below sea
level. Samples were secured of the water from a flowing artesian well which irri-
gates the little group of palms near the bordj, and which in spite of its bad quality
is used for drinking and for cooking purposes.
About a mile to the eastward and at a somewhat lower level is a date plantation of
some size, the property of a French company. Here samples were secured of the
artesian water used to irrigate this plantation. Analyses are given herewith of the
water of the two artesian wells at Chegga, made by Mr. Seidell, and also the analysis
by Carnot& (of the Ecole des Mines, Paris) of the water from the Bir Djefair well,
some 6 miles north of Chegga.
A bordj is a fortified shelter for travelers, such as is common in Algeria.
& Holland, Hydrologie du Sahara, p. 294.
ALKALI CONDITIONS AT CHEGGA.
8.5
TABLE 18. Composition (in percentage by weight) of artesian water at Chegga and of the
well at Bir Djefa'ir, Algeria.
Locality.
Calcium
carbon-
ate.
Magne-
sium car-
bonate.
Iron car-
bonate.
Calcium
sulphate.
Magne-
sium sul-
phate.
Sodium
sulphate.
Sodium
chlorid.
1790
0629
2067
OAOAO
Cheggsi date plantation 1
2062
0966
1215
1955
Bir Djefair 2
01536
00187
00102
17784
08632
06214
O'SJWvl
Locality.
Potassi-
um chlo-
rid.
Sodium
carbon-
ate.
Sodium
bicarbon-
ate.
Silica.
Nitrates
and
soluble
organic
matter.
Organic
and
mineral
matter in
suspen-
sion.
Total.
Chegga, Bordj !
0. 0133
0.0030
0.0033
5485
Chegga, date plantation 1 . . .
.0127
.0030
.0046
.6401
BirDjefaira
.00632
0. 00480
00030
00280
41291
1 Mr. Seidell's original analyses of artesian water of Chegga are as follows :
Well at date plan-
tation.
Well at Bordj
(drinking water).
Alkali
per 100 cc.
Composi-
tion of
alkali.
Alkali
per 100 cc.
Composi-
tion of
alkali.
Ca ..
Gram.
0.0607
.0195
.1190
.0067
.3047
.0017
.0033
.1245
Per cent.
9.48
3.05
18.59
1.05
47.60
.27
.51
19.45
Gram.
0.0527
.0127
.1008
.0070
.3162
.0017
.0024
.0550
Per cent.
9.61
2.32
18.37
1.28
57.65
.31
.44
10.02
Mg
Na\.
K
SO 4 ...
CO-,
HCCN...
ci
Total
.6401
100.00
.5485
100.00
CaSO 4 . .
.2062
.0966
.0127
.1215
.1955
.0030
.0046
32.22
15.09
1.98
18.98
30.54
.47
.72
.1790
.0629
.0133
.2067
.0803
.0030
.0033
32.63
11.47
2.42
37.69
14.64
.55
.60
MgSC-4
KC1.
NaoSOj
NaCl. .
NaCO,...
NaHCO 3 .
Total
.6401
100.00
.5485
100.00
2 Holland, Hydrologie du Sahara.
The preponderance of sulphates is marked in the water of the well used to irrigate
the date plantation. They constitute 66. 28 per cent of the total soluble salts, whereas
the chlorids make up only 32.529 per cent.#
The contrast with Fougala is most striking. There the artesian water was very
pure, containing only about 0.085 per cent of dissolved salts, whereas at Chegga the
water contained 0.6401 per cent, or nearly eight times as much alkali. This water
The analyses made by Lahache (Archives de medicine milit., vol. 14 (1889), p. 50)
have shown the existence of soluble nitrates in the artesian water of all regions of the
Algerian Sahara. At Chegga 22.5 grams per cubic meter were found, or 0.00023 per
cent, corresponding closely to the 0.00030 per cent of nitrates and dissolved organic
matter reported by Carnot in the analysis of the water of the well at Bir Djefair.
No nitrates were found by Mr. Seidell, though tests were made. Possibly the small
amounts present had been consumed by micro-organisms before the water was
analyzed. The nitrates present in the artesian water are considered by Marcassin
(Annal. Inst. Nat. Agron., 1895) to be of considerable importance in supporting the
date palm and other vegetation grown by irrigation in the Algerian Sahara.
86
THE DATE PALM.
would be counted too alkaline to use for irrigation anywhere outside of the Sahara,
though at Chegga it is the only water used to irrigate a flourishing date orchard
planted on soil originally very alkaline, but which has been improved, even while
being irrigated with such water, by means of drainage ditches into which the excess
of alkali has been washed. Figure 1 on Plate XVI shows the appearance of these
palms growing where alkali can be seen at the side of the irrigation ditches. Figure
2 on the same plate shows a reclaimed area where Saharan alfalfa was growing.
Station No. 1 at Chegga was in the date plantation in a very alkaline spot, close to
an offshoot that had failed to grow, probably because of the excess of alkali in the
soil. The subsoil was taken from the side of the drainage ditch, some 18 feet away,
and may not represent the true state of the subsoil where the surface soil and crust
were taken.
The crust shows the following amounts of alkali soluble in an excess of water (20
times weight of soil sample):
TABLE 19. Per cent of alkali soluble in excess of water in surface crust from, Station No. 1,
Chegga, Algeria. 1
Locality.
Calcium
sulphate.
Magne-
sium sul-
phate.
Sodium
sulphate.
Sodium
chlorid.
Potas-
sium
chlorid.
Sodium
bicar-
bonate.
Sodium
carbon-
ate.
Total.
Chegga, Station 1,
surface crust
3.76
1.68
55.44
2.87
0.15
0.16
0.06
64 12
The soil shows the following amounts of alkali:
TABLE 20. Per cent of alkali in soil of date plantation, Station 1, Chegga, Algeria. 1
Depth.
Calcium
sulphate.
Magne-
sium
sulphate.
Sodium
sulphate.
Sodium
chlorid.
Potas-
sium
chlorid.
Sodium
bicar-
bonate.
Total.
02
0.20
4.89
0.53
10
08
5 82
Subsoil at 3 feet .
.02
.25
1.50
.80
.08
.06
2.71
Soil 1 to 4 feet (estimated)
(2.61)
(.*
2)
(.07)
(3.50)
1 Mr. Seidell's original analyses of the samples from this station are as follows:
Crust.
Soil, 0-12 inches.
Subsoil, 36 inches.
Alkali in
soil.
Composi-
tion of
alkali.
Alkali in
soil.
Composi-
tion of
alkali.
Alkali in
soil.
Composi-
tion of
alkali.
Ca
Per cent.
1.11
.34
19.18
.08
41.46
1.81
.12
.03
Per cent.
1.72
.53
29.90
.12
64.68
2.82
.18
.05
Per cent.
0.97
.04
1.81
.06
5.79
.36
.06
Per cent.
10.68
.44
19.94
.71
63.63
3.94
.66
Per cent.
0.96
.05
.82
.04
3.51
.52
.04
Per cent.
16.12
.84
13.77
.74
59.03
8.82
.68
Mg
Na
K
So 4
Cl
HCC-Q
CO,
Total -...
64.13
100.00
9.10
100.00
5.94
100.00
CaSth
3.76
1.68
.15
2.87
55.44
.16
.06
5.85
2.62
.23
4.47
86.49
.25
.09
3.30
.20
.10
.53
4.89
.08
36.30
2.18
1.12
5.80
53.70
.90
3.25
.25
.08
.80
1.50
.06
54.75
4.18
1.42
13.47
25.24
.94
MgSCXi
KCl
NaCl
NaoSO 4
NaHCO {
Na^COs
Total
64.13
100.00
9.09
100.00
5.94
100.00
aThe Chegga water contains over 374 grains of alkali per gallon; whereas 40 grains is usually given
as the limit for drinking water, and anything above this is considered doubtful for irrigating pur-
poses, unless the salt in solution is gypsum. Even excluding gypsum, the Chegga water still con-
tains 250 grains to the gallon, whereas the water of Lake Elsinore, which so disastrously affected the
orange groves on which it was used near Riverside, Cal., contained only 84 to 116 grains per gallon.
(See Report, California Agricultural Experiment Station, 1897-98, pp. 99-113 and 126-130.)
ALKALI CONDITIONS AT CHEGGA.
87
The amount of alkali is enormous, the largest found in a date plantation in the
Sahara, and is probably more than young offshoots just rooting can stand, as is
evidenced by the death of one planted not long before the sample was taken. Older
palms can doubtless endure this amount of alkali, for several were growing near by
in soil apparently identical with the sample analyzed. It should be noted that the
bulk of the alkali (some 70 per cent of all the alkali present and 2.35 per cent of
the total weight of the soil), is sodium sulphate (Glauber's salt), and only 23 per
cent of the alkali, or 0.82 per cent of the total weight of the soil, is composed of
chloride, whereas at Fougala, Station 1, where the alkali was also almost strong
enough to prevent the growth of the date palm, the total alkali content of the soil
was much less, being some 2.46 per cent instead of 3.53 per cent, but consisted of
1.98 per cent of chlorids, more than twice as much as at Chegga. The chlorids
are, however, without doubt more injurious than sodium sulphate, and both of these
stations are to be considered as representing very nearly the limit of endurance of
the date palm Fougala for chlorids; Chegga for sulphates.
The surface accumulation of sodium sulphate, as suggested by Mr. Seidell, may
wejl have some connection with the composition of the very alkaline waters used for
irrigation in which the sulphates predominate and in which sodium sulphate is pres-
ent to the extent of 121.5 parts per 100,000, constituting 18.98 per cent of the dissolved
salts (see p. 95).
Station No. 2, at Chegga (PI. XVI, fig. 2), is very unlike the first, as it represents
reclaimed land where Saharan alfalfa** was growing. It is to be noted that deep
drainage ditches ran through the orchard at 50 to 60 feet intervals and provided escape
for the superabundant alkali, and that this sample was secured near one of these
ditches as may be seen in Plate XVI, figure 2. The analysis is given herewith.
TABLE 21. Per cent of alkali in washed-out surface soil of date plantation, station No. 2,
Chegga, Algeria. l
Depth.
Calcium
sulphate.
Magne-
sium
sulphate.
Sodium
sulphate.
Sodium
chlorid.
Potas-
sium
chlorid.
Sodium
bicar-
bonate.
Total.
Surface foot
0.02
0.17
0.04
0.05
0.05
0.06
039
1 Mr. SeidelFs original analysis of the samples from this station is as follows:
Alkali in
soil.
Composi-
tion of
alkali.
Alkali in
soil.
Composi-
tion of
alkali.
Ca
Per cent.
1.04
Per cent.
26.57
CaSC-4 . .
Per cent.
3.54
Per cent.
90.29
Mg
03
87
MgSCU
.17
4.29
Na
.05
1.28
KC1...
.05
1.38
K
03
.72
NaCl
.05
1.33
SOi
2 65
67 81
Na2SO 4
.04
1.02
Cl
.06
1.53
NaHCO 3
.06
1.69
HCO 3
.05
1.22
*
Total
3 91
100.00
Total
3.91
100.00
This soil shows a very low per cent of alkali, considering that the date plantation
is on a very alkaline area and that the water used for irrigating is very brackish.
This is almost the same amount of alkali as was found in the valley of the Colorado
River near Yuma, where alfalfa grew in soil containing 0.498 per cent of alkali in the
4 upper feet (Loughridge, Bull. 133, California Agricultural Experiment Station, p.
27) . However, at Yuma the irrigation water was of good quality, containing less than
0.1 per cent of dissolved salts, whereas at Chegga the water was very bad, containing
over 0.64 per cent of alkali.
See footnote a, p. 23.
88
THE DATE PALM.
Station No. 3, at Chegga, represents a subsoil thrown up in digging a drainage ditch
and was so charged with alkali as to have become nearly solid. The soil canie from
a depth of 4 to 6 feet, and contains the following amounts of alkali:
TABLE 22. Per cent of alkali in subsoil of date plantation, station No. 3, Chegga, Algeria. 1
Depth.
Calcium
sulphate.
Magne-
sium
sulphate.
Sodium
sulphate.
Sodium
chlorid.
Potas-
sium
ehlorid.
Sodium
bicar-
bonate.
Total.
Subsoil 4 to 6 feet
0.02
0.33
0.22
1.16
0.06
07
1 86
1 Mr. Seidell's original analysis of the sample from this station is as follows:
Alkali in
soil.
Composi-
tion of
alkali.
Alkali in
soil.
Composi-
tion of
alkali.
Ca...
Per cent.
1.11
Per cent.
19.77
CaSO 4 . . .
' Per cent.
3.76
Per cent.
67 17
Mg
06
1 18
MgSCv
33
5 82
Na...
.55
9.74
KC1. .
.06
1.14
K
.03
.61
NaCl
1 16
20 66
so.
3 07
54 71
NaoSO 4
22
3 96
Cl
.73
13.06
NaHCO 3
07
3 25
HCO 3
05
93
Total
5 60
100 00
Total
5 60
100 00
Though less alkaline than the subsoil of sample No. 1, which contained 2. 765 per
cent, this still shows a very high salt content.
When date palms were first planted on this property, many of the offshoots were
lost through excessive alkalinity. The digging of drainage ditches has rendered it
possible to wash out much of the alkali, even with the very bad water used for
irrigation, as' is evidenced by the fact that alfalfa can now grow on some of the land.
ALKALI CONDITIONS IN RELATION TO DATE CULTURE AT M'RAIER, ALGERIA.
Going southward from Chegga, the Little Desert of Moran is traversed until a
somewhat abrupt descent is reached, which is marked by a series of low cliffs called
Kef el Dohr. At the base of this declivity there extends an almost unbroken plain,
which slopes gently to the eastward to the shores of the salt lagoon, ChottMelrirh, or
rather a branch of it called Chott Merouan (see map, PL II, p. 76). This salt lagoon
is often dry, but always contains mud covered with a white crust of salt two-fifths
of an inch or more thick. In proceeding southward, the road skirts the edge of the
lagoon, and during the heat of the day the most deceptive mirages are seen in look-
ing across the Chott (PL XVIII, fig. 2) .
This region is remarkably like the Salton Basin in many ways, and Chott Melrirh,
like Salton Lake, is below sea level, the lowest part or the western border of Chott
Melrirh being some 100 feet (31 meters) below sea level. The plain to the west is flat
and extremely arid. Occasional small sand dunes occur, which are like those in the
Salton Basin.
The oasis of Ourir, seen in passing, is one of the largest created by the French set-
tlers, containing some 40,000 date palms. It is 42 feet (13 meters) below the sea
level.
A stop was made at M'rai'er, an oasis of considerable size (some 60,000 date palms)
owned by Arabs. It is from 10 to 12 feet below sea level. In the village of M'rai'er is
a very saline area, where the scanty vegetation is composed of stunted saltbushes, sam-
phires, etc. The water level was only a few inches below the surface. A stunted date
palm grew some 15 feet away from the spot where the soil sample was obtained, but
The lowest part of Salton Lake is some 270 feet below sea level.
ALKALI CONDITIONS AT OURLANA.
89
at the side of a drainage ditch. The surface crust obtained here shows the following
composition, as analyzed by Mr. Seidell, by extracting with an excess of water 20 times
the weight of the sample:
TABLE 23. Per cent of alkali soluble in excess of water, in surface crust from Mrdier,
Algeria. l
Depth.
Calcium
sulphate.
Magnesi-
um sul-
phate.
Sodium
sulphate.
Sodium
chlorid.
Potassi-
um chlo-
rid.
Sodium
bicar-
bonate.
Total.
Surface crust
4 66
12 31
8 92
29 ig
98
27
56 32
r. Seidell's original analysis of the sample from this station is as follows:
-
Alkali in
sample.
Compo-
sition of
sample.
.
Alkali in
sample.
Compo-
sition of
sample.
Ca ..
Per cent.
1 37
Per cent.
2 43
CaSO 4 .
Per cent.
4 66
Per cent.
8 27
Mg .
2.48
4.41
MgSCv
12 31
21 86
Na
14.46
25.68
KCL.:.
.98
1 74
K
.52
.92
NaCl
29 18
51 8 9
So 4 ..
19.14
33.98
NaHCOg
.27
48
Cl
18.15
32.23
NaoSO 4
8 92
15 83
HCO 3
20
35
Total
56 32
100 00
Total
56.32
100.00
This crust is remarkable among those collected in the Sahara for its low content of
calcium sulphate (8.277 per cent of total alkali) and the high content of magnesium
sulphate (21.86 per cent of total alkali). The extreme sterility of the sink where the
sample was secured may be due in part to the excess of magnesium over lime, which
has been shown by Loew a to be very injurious to most plants. This was the only
sample obtained in the Sahara, where magnesium sulphate was in excess of gypsum.
Common salt makes up one-half (52 per cent) of the crust.
ALKALI CONDITIONS IN RELATION TO DATE CULTURE AT OURLANA, ALGERIA.
Going southward from M'rai'er one soon enters the Oued Rirh region proper. The
Oued Rirh or Rirh River is a chain of chotts (salt lagoons or dry salt beds) occupy-
ing a partially filled up, dry valley, which runs from Tougourt almost due north to
the Chott Melrirh, with a gradual fall to the north, amounting to some 270 feet in the
70 miles from Bledet Amar & to Chott Merouan (see map, PI. II, p. 76) . The Oued
Rirh has a very shallow valley, bordered on the west by a nearly flat plain of sandy
loam soil (largely planted to date palms), which rises gradually toward the barren
hills, which are reached at a distance of from one-half to 10 miles from the valley.
To the east of the chain of Chotts this country is sandy, and dunes occupy most of
the surface. Small dunes sometimes occur on the west side of the valley.
This valley is some 200 feet above sea level at Tougourt and is slightly below sea
level where it enters the Chott Merouan. It is abundantly supplied with flowing
artesian wells and is one of the most celebrated date regions in the world. The
famous Deglet Noor date, reported in Tunis to have originated in the oasis of Bledet
Amar near Temacin at the southern end of the Oued Rirh, is largely grown here and
constitutes almost the sole export. In all parts of the Oued Rirh date culture is the
chief industry, and in many oases the date is the only plant grown, as the very
Loew, O. Relation of Lime and Magnesia to Plant Growth, Bui. No. 1, Bureau
of Plant Industry, U. S. Dept. of Agriculture, and also Kearney and Cameron, Report
71, U. S. Dept. of Agriculture.
& Marked Bled et Ahmar in the map, Plate II, page 76.
90 THE DATE PALM.
alkaline soil and the high salt content of the irrigation water preclude other profitable
cultures.
The artesian water at Ourlana, as elsewhere in the Oued Rirh, is confined below a
compact stratum of pudding stone which lies some 175 to 250 feet below the surface.
Below this pudding stone is a layer of loose quartz sand, more or less mixed with
pebbles, which contains an abundant supply of water under sufficient pressure to
give a ready flow, frequently to the tops of the lower hillocks in the plain.
The French engineers Jus and Holland, who have studied exhaustively the ques-
tion of the origin of the water supply of the Oued Rirh, agree in believing that the
original source is in the Atlas Mountains to the north, where the heavy rainfall and
snowfall (some 5^ feet annually) is absorbed by the upturned cretaceous strata and
conducted in these strata to the south, where it first reappears in the great springs
of the Zab region along the northern border of the Sahara. The water of these
springs and of many others which are believed to exist, though the water never
reaches the surface, soaks into the pervious strata of the Saharan formation and flows
southward toward the Oued Rirh country, o becoming imprisoned beneath an imper-
vious pudding-stone layer, except where natural openings exist and allow the water
to reach the surface & or where artesian wells have been put down.
On the 1st of October, 1885, Oued Rirh contained 114 flowing wells put down by
the French and tubed with iron, 492 flowing wells constructed by the natives, and 22
natural springs, which were used for irrigating. The total supply of water furnished
by these wells and springs was 253,698 liters per minute, or 4 cubic meters (over
1,050 gallons) per second, having an average temperature of 25.1 C. The largest
flowing well is No. 4, at Sidi Amran, which was put down in 1884. It flows 6,000
liters per minute.
The beneficial effect of French occupation has been very marked in the Oued
Rirh, where in 1856 there were 33 oases, all in a state of decay. They were nourished
by 58,000 liters of water per minute and contained only 136,000 date palms, for the
most part old and yielding but little fruit. Thirty years later, thanks to the artesian
wells put down by the French, the total yield of water had been raised to more than
253,000 liters per minute; all the old oases had been put in a flourishing condition
and new ones had been created, so that in 1885 there were 43 oases containing
509,375 date palms in full bearing, and about 138,000 young palms from 1 to 7 years
old. The native population had more than doubled during this time and the value
of the oases had increased more than fivefold.
The oasis of Ourlana, of which a special study was made, is located nearly 100
miles south of Biskra, at an altitude of 113 feet above sea level, and is in the most
fertile part of the Oued Rirh. Within a radius of 10 miles of Ourlana there are no
fewer than 15 oases irrigated from 32 artesian wells (30 of which are modern tubed
wells of French construction) and from 16 springs " behour." These 15 oases con-
tained in 1882 over 182,000 date palms, and nearly half of these oases have been
much enlarged since then, so that they now, doubtless, contain over 200,000 date
palms.
The water of these springs of the western Zab contains on the average 0.203 per
cent of dissolved salts. Those springs which reach the surface indirectly after filter-
ing a distance through the superficial strata yield water showing a larger per cent of
alkali about 0.268 per cent on the average and by the time the water has^soaked its
way through the Saharan strata and flowed to the Oued Rirh country, the alkali con-
tent has risen to an average of 0.487 per cent.
& Forming the springs and small lagoons called " behour" and "chria" by the
Arabs.
ALKALI CONDITIONS AT OUKLANA.
91
The well Puits Desveaux from which the plantation was irrigated, yields an
abundant supply of very alkaline water. Mr. SeidelFs analysis is as follows:
TABLE 24. Composition of artesian water (Puits Desveaux) used to irrigate date plantation
at Ourlana, Algeria. l
Calcium
sulphate.
Magne-
sium
sulphate.
Magne-
sium
chlorid.
Sodium
chlorid.
Potas-
sium
chlorid.
Sodium
carbon-
ate.
Sodium
bicarbon-
ate.
Total.
Composition in grams
per 100 cc. (percent-
age bv weight)
0. 2327
0.0645
0.0690
0. 2478
0. 0143
0.0030
0.0040
6353
Percentage of total
salt content
36.70
10.13
10.85
38.98
2.25
.47
.64
100 00
*Mr. Seidell's original analysis of the artesian water of Ourlana is as follows:
Alkali
per 100 cc.
Composi-
tion of
alkali.
Alkali
per 100 cc.
Composi-
tion of
alkali.
Ca...
Gram.
0685
Per cent.
10 78
CaSO 4 . .
Gram.
2327
Per cent.
38 70
Mg ..
.0305
4.80
MgSCv . .
.0645
10.13
Na
.1001
15 75
MgClo
0690
10 85
K
. 0075
1.18
KC1-.
.0143
2.25
SO 4
.2155
33.91
NaCl
2478
38 98
co s
.0017
.27
NaoCCv}
.0030
.47
HCO,
.0030
.47
NaHCO 3
.0040
64
Cl
.2085
32.83
Total
6353
100 00
Total
6353
100 00
In contrast to the water of Chegga (see p. 85), having almost the same amount of
dissolved salts, in which the sulphates predominated, the chlorides are here in excess,
constituting 52 per cent of the total dissolved salts, while the sulphates make up
46.83 per cent. The average of 26 analyses of the water from flowing artesian
wells in the Oued Rirh is given by Holland as follows:
TABLE 25. Average composition (in percentage by weight) of 26 samples of artesian water
from the Oued Rirh, Algeria.
Sulphates 0.25436
Chlorids 21279
Carbonates 01257
Nitrates and dissolved organic matter 00411
Silicates and suspended matter 00310
Total....; 48693
It will be noticed that the sulphates preponderate over the chlorids in this table,
though not so much as in the Chegga water.
Station No. 1 at Ourlana was near the bordj and not far from the well. Young
and old date palms were growing near by in good condition. There was an open
drainage ditch near by, but this did not prevent the formation of a surface crust of
alkali. At 36 inches below the surface water was found, and below that level the
sand was very wet, resembling quicksand.
Holland, Hydrologie du Sahara, p. 260.
92
THE DATE PALM.
The surface crust showed the following composition:
TABLE 26. Per cent of alkali soluble in excess of water in surface crust, from. Station No. 1,
Ourlana, Algeria. 1
Calcium sulphate 3. 21
Magnesium sulphate 2. 67
Magnesium chlorid 71
Sodium chlorid i 7. 52
Potassium chlorid 29
Sodium bicarbonate .12
Total . . 1 4. 52
The soil to a depth of 4 feet showed the following amounts of alkali:
TABLE 27. Per cent of alkali in soil of date orchard, Station No. 1, at Ourlana, Algeria. 1
Depth.
Calcium
sulphate.
Magnesi-
um sul-
phate.
Sodium
chlorid.
Potassi-
um chlo-
rid.
Magnesi-
um bicar-
bonate.
Sodium
bicar-
bonate.
Total.
Surface foot
05
16
23
03
03
03
53
Subsoil 12 to 24 inches
.05
.11
.16
.01
.04
37
Subsoil 24 to 36 inches
05
09
12
03
03
32
Subsoil 36 to 48 inches
.05
.10
.13
.02
.02
03
36
Soil, 1 to 4 feet
.1
65
.]
8
15
39
Seidell's original analyses of the samples from this station are as follows:
Crust.
Soil (0-12
inches).
Subsoil (12-24
inches).
Subsoil (24-36
inches).
Subsoil (36-48
inches).
Alkali
in soil.
Compo-
sition
of
alkali.
Alkali
in soil.
Compo-
sition
of
alkali.
Alkali
in soil.
Compo-
sition
of
alkali.
Alkali
in soil.
Compo-
sition
of
alkali.
Alkali
in soil.
Compo-
sition
of
alkali.
Ca ..
Per ct.
0.95
.72
2.99
.15
4.40
5.23
.08
Per ct.
6.51
4.96
20.62
1.04
30.30
35.99
.58
Per ct.
0.75
.04
.10
.01
1.95
.15
.04
Per ct.
24.80
1.18
3.22
.53
63.83
5.06
1.38
Per ct.
0.30
.03
.06
.01
.80
.10
.03
Per ct.
22.43
2.12
4.54
.45
60.32
7.87
2.27
Per ct.
0.24
.02
.05
.01
.65
.08
.03
Per ct.
22.16
2.20
4.21
1.28
59.71
7.69
2.75
Per ct.
0.26
.02
.06
.01
.69
.09
.04
Per ct.
21.77
2.04
5.10
1.02
58.84
7.83
3.40
Mg.
Na
K
SCM
Cl...
HCO 3
Total
14.52
100.00
3.04
100.00
1.32
100. 00
1.09
100.00
1.17 100.00
CaSO 4 . . .
3.21
2.67
.29
7.52
.12
.71
22.13
18.39
1.99
51. 78
.80
4.91
2.56
.16
.03
.23
.03
84.28
5.40
.99
7.57
.99
1.00
.11
.01
.16
75. 95
8.32
.90
12.11
.82
.09
.03
.12
75.27
8.24
2.38
10.81
.87
.10
.02
.13
.03
73.98
8.33
1.87
11.40
2.38
MgSCXi
KC1 . .
NaCl
NaHCOg
MgClo
MgHCO 3
.03
.77
.04
2. 72
.03
3.30
.02
2.04
Total
14.52
100.00
3.04
100.00
1.32
100.00
1.09
100.00
1.17
100.00
The fourth foot from the surface, where the subsoil was full of water, shows a
larger amount of alkali than does the third foot. This amount of alkali w T as evi-
dently without effect on the date palm.
Station No. 2 at Ourlana (PI. XVII, fig. 1) was of much interest, because located
between old and flourishing date palms which had been planted ten years or more.
Notwithstanding the existence of a drainage ditch only a few feet away and of the
fact that the irrigation water had been applied to the whole surface of the soil by
flooding, the surface still showed a considerable crust of alkali. Water was
encountered at a depth of 30 inches, which was below the level of the shallow
drainage ditch.
ALKALI CONDITIONS AT OURLANA.
The surface crust showed the following composition:
TABLE 28. Per cent of alkali soluble in excess of water in surface crust, Station No. 2,
Ourlana, Algeria. l
Calcium sulphate 4. 88
Magnesium sulphate 2. 57
Magnesium chlorid 60
Sodium chlorid 10. 15
Potassium chlorid .11
Sodium bicarbonate .12
Total 18. 43
The following table shows the amount of alkali in the soil:
TABLE 29. Per cent of alkali in soil of date plantation, Station No. 2, Ourlana, Algeria. l
Depth.
Calcium
sulphate.
Magne-
sium
sulphate.
Magne-
sium
chlorid.
Sodium
chlorid.
Potas-
sium
chlorid.
Sodium
bicarbon-
ate.
Total.
Surface foot
0.05
0.15
0.27
0.90
0.05
07
1 49
Subsoil 30 to 34 inches
05
15
17
03
08
48
Soil, 1 to 4 feet (estimated) .
(.!
'0)
(.445)
(.077)
(.72)
1 Mr. Seidell's original analyses of the samples from this station are as follows:
Crust.
Soil (0-12 inches).
Subsoil (30-34
inches).
Alkali
in soil.
Compo-
sition of
alkali.
Alkali
in soil.
Compo-
sition of
alkali.
Alkali
in soil.
Compo-
sition of
alkali.
Ca...
Per cent.
1.44
.67
4.03
.06
5.49
6.65
.09
Per cent.
7.79
3.65
21.88
.31
29.80
36.08
.49
Per cent.
1.24
.10
.37
.03
3.09
.77
.05
Per cent.
21.91
1.77
6.61
.50
54.63
13.64
.95
Per cent.
1.02
.03
.09
.02
2.57
.12
.06
Per cent.
26.15
.76
2.30
.46
65.77
3.02
1.54
Mg..
Na
K ....
SOi
ci..
HCO 3
Total
18.43
100.00
5.65
100.00
3.91
100.00
CaSO 4
4.88
2.57
.60
.11
10. 15
.12
26.47
13.94
3.27
.60
55. 05
.67
4.21
.15
.27
.05
.90
.07
74.41
2.65
4.84
.92
15.87
1.31
3.48
.15
88.89
3.79
MgSO 4
MgClo
KC1 ..
.03
.17
08
.82
4.40
2.10
NaCl
NaHCO-,
Total . ..
18.43
100.00
5.65
100.00
3.91
100.00
The date palms were growing luxuriantly and fruiting abundantly here, entirely
unaffected by the alkali, though they must withstand nearly one-half per cent of
chlorids. It is interesting to note that over 60 per cent of the land surveyed by the
Bureau of Soils in the Salton Basin has less alkali than was contained in this soil.
Station No. 3 at Ourlana was situated about half a mile from the bordj, in a low
and badly drained part of the orchard, where the palms did not look so vigorous and
healthy as they did elsewhere. Below 26 inches' depth the sand was full of water
and perfectly fluid, like quicksand.
94
THE DATE PALM.
The surface crust showed the following composition:
TABLE 30. Per cent of alkali soluble in excess of water in surface crust, Station No. 3,
Ourlana, Algeria. 1
Calcium sulphate 3. 23
Magnesium sulphate 03
Magnesium chlorid 49
Sodium chlorid 1. 20
Potassium chlorid 07
Sodium bicarbonate . . .12
Total
The following table shows the amount of alkali in the soil:
TABLE 31. Per cent of alkali in soil, Station No. 3, Ourlana, Algeria. 1
Depth.
Calcium
sulphate.
Magne-
sium
sulphate.
Magne-
sium
chlorid.
Sodium
chlorid.
Potas-
sium
chlorid.
Sodium
bicarbon-
ate.
Total.
05
08
04
02
08
27
Subsoil ' 12 to 26 inches
.05
.09
.04
.04
.07
.29
Subsoil 26 to 30 inches
05
04
07
.11
.04
07
38
Soil, 1 to 4 foot ( estimated )
(<
)7)
(.19)
.07
.33
!Mr. Seidell's original analyses of the samples from this station are as follows:
Crust.
Soil (0 to 12 inches).
Subsoil (12 to 36
inches) .
Quicksand (26 to
30 inches).
Alkali in
soil.
Composi-
tion of
alkali.
Alkali in
soil.
Composi-
tion of
alkali.
Alkali in
soil.
Composi-
tion of
alkali.
Alkali in
soil.
Composi-
tion of
alkali.
Ca .
Per cent.
0.95
.13
.50
.04
2.31
1.13
.08
18.49
2.57
9.81
.70
44.88
21. 92
1.63
Per cent.
0.90
.02
.04
.01
n.15
.10
.06
27.35
.67
1.15
.36
65.67
2.98
1.82
Per cent.
1.05
.02
.04
.02
2.52
.11
.05
27.54
.57
.94
.63
66.03
2.88
1.41
Per cent.
1.02
.03
.06
.02
2.48
.14
.05
26.81
.68
1.68
.63
65.10
3.68
1.42
Me
N::
K
BOi..
Cl
KCO 3
Total
5.14
100.00
3.28
100.00
3.82
100.00
3.80
100.00
CaSO 4
3.23
.03
.49
.07
1.20
.12
62.84
.66
9.61
1.32
23.32
2.25
3.05
93.01
3.58
93.56
3.47
.04
.07
.04
.11
.07
91.05
1.05
1.84
1.16
2.95
1.95
MgSO 4
MgClo
.09
.02
.04
.08
2.61
.67
1.21
2.50
.09
.04
.04
.07
2.25
1.15
1.10
1.94
Kci. 2 .:::::::::::::::
NaCl
NaHCOy
Total
5.14
100. 00
3.28
100.00
3.82
100. 00
3.80
100.00
This soil is unique among those analyzed in showing a slight but evident increase
in the alkali content, especially of the harmful chlorids, as the depth increases and
a predominance of magnesium chlorid over the other chlorids in the upper layers
of the soil.
Mr. Seidell called the writer's attention to the influence of the composition of the
irrigating water on the nature of the alkali.
The rather unusual occurrence of chlorids of the alkaline earths in the water
which contains magnesium chloride to the amount of 0.069 per cent is paralleled by
the occurrence of the same salts in large amounts in all the surface crusts from Our-
lana. There can be no doubt that the composition of the alkali as it now exists in
the soil of the date orchards of Ourlana is profoundly influenced by the alkali left in
ALKALI CONDITIONS AT OURLANA.
95
the soil by the evaporation of the water used for irrigation. Three acre-feet of such
water, the least amount needed per annum, would carry on to the land no less than
50,000 pounds of dissolved salts, and, subtracting the excess of gypsum, some 40,000
pounds of harmful alkali, or 0.1 per cent of the surface foot of soil and 0.025 per cent
of the 4 upper feet of soil. Of course, some of the water drains off directly, and
even leaches alkali out of the soil, but much remains in the soil, and on evaporating
leaves the alkali behind.
After a number of years' irrigation with strongly alkaline water such as that of
Ourlana a condition of approximate equilibrium is reached between the amount of
alkali carried to the land and the amount leached out by the drainage water. The
composition of the alkali in a soil in such a condition doubtless depends much more
on the composition of the irrigation water than on the character of the alkali orig-
inally present in the soil before irrigation was practiced. The influence of the com-
position of the irrigation water on the nature of the alkali is naturally most clearly
marked on lands that are well leached out by means of irrigation for a long period of
time with an abundance of water, accompanied with thorough drainage.
A comparison of the composition of the alkali at two such stations, one at Chegga
and one at Ourlana, is of interest, because the artesian waters used for irrigation at
these two localities contain almost identical amounts of dissolved salts, though of
very different composition. The following tabulation shows the proportions of the
principal salts in the water and in the surface soil:
TABLE 32. Proportions of sulphates and chlorids present in alkali of irrigation water and
in well-drained long-irrigated surface soils at Chegga and Ourlana, Algeria.
Total
Station.
Sulphates
in alkali
(parts per
Chlorids
in alkali
(parts per
amount of
alkali
(in percent-
100 of total
alkali) .
100 of total
alkali).
weight of
water or
soil).
Chegga artesian water (well by date plantation)
66.28
32.53
0. 6401
('lu" r g'a surface soil (Station No 2)
58.97
25.64
.39
( hirlana artesian water ( Puits Desveaux)
46.83
62.08
.6353
Ourlana surface soil (Station No 1) .
39. 62
49.06
.53
It is clear from this table that sulphates preponderate at Chegga, both in the irri-
gation water and in the alkali of well-drained surface soil after irrigation for a term
of years, while at Ourlana the preponderance of chlorids, though not so great as
that of the sulphates at Chegga, is nevertheless plainly marked. In both surface
soils the approximation in composition of the alkali of the surface soil to that in the
irrigation water is evident, and is rendered still more clear by a study of the bases.
Magnesium, for example, is decidedly more abundant in the artesian water at Our-
lana than at Chegga, and in consequence the surface soils at Ourlana likewise show
more magnesium than those of Chegga.
All three Ourlana stations show amounts of alkali large enough to be dangerous to
ordinary crops, and, in fact, in this oasis no other cultures were observed such as were
followed at the other oases studied, and all three stations show a pronounced surface
crust in spite of long-continued irrigation, accompanied with drainage by open
ditches. The sandy nature of these soils and their consequent low water content
cause the concentration of the soil water to be much higher in proportion to the per-
centage of alkali present than in heavier soils having a greater water content, such
as those of Biskra, for example (see p. 77). There is then every evidence that the
date palm is unharmed by these quantities of alkali, even when irrigated by water
of very bad quality, full of harmful chlorids.
96
THE DATE PALM.
In Table 33 are given the results of the analyses of the soils from the ten Saharan
stations where samples were obtained. The alkali content of the soil is expressed
in percentages of the total weight of the soil, as in the preceding pages. All esti-
mated quantities are inclosed in parentheses.
TABLE 33. Percentage of alkali in Salwran soils where date culture is possible and in
artesian water used to irrigate date plantations.
Station and. depth.
Sul-
phates.
Chlo-
rids.
Bicar-
bon-
ates.
Car-
bon-
ates.
Total
alkali.
Remarks.
BISKKA, STATION NO. 1.
Surface foot
0.05
.05
1.92
.76
.28
(.22)
(.38)
.34
.20
.12
.09
.21
.09
.17
.09
(.12)
5.11
1.77
(2.61)
.23
.57
.21
.16
.14
.15
.165
.20
.20
(-20)
.05
.05
.09
(.07)
0.08
.08
9.72
4.08
1.46
(1-10)
(1.98)
l.*66.
.23
.17
.04
.54
.08
.11
.07
(.08)
.63
.88
(.82)
.10
1.22
.26
.17
.15
.15
.18
1.22
.20
(.445)
.14
.17
.22
(.19)
0.05
.06
.12
.08
.10
(.08)
(.08)
.08
.08
.09
.08
.084
.09
.10
.08
(.09)
.08
.06
(.07)
.06
.07
.06
.04
.03
.05
.045
.07
.08
(.077)
.08
.07
.07
(.07)
0.18
.19
11.76
4.92
1.82
(1.40)
(2.44)
1.98
.51
.38
.31
.83
.28
.38
.24
(.29)
5.82
2.71
(3.50)
.39
1.86
.53
.37
.32
.35
.392
1.49
.48
(.72)
.27
.29
.38
(.33)
lln an old and flourishing
/ date plantation.
Undisturbed desert soil ad-
joining young date-palm
plantation.
Young date plantation in
good condition.
Old flourishing date planta-
> tion; soil washed out by
continued irrigation.
1 Date palms barely able to
| grow.
Washed-out surface soil.
Saharan alfalfagrowshere.
Formed a solid crust on ex-
posure to air.
Flourishingdate plantation.
[Flourishing old date planta-
( tion.
1 Dates less vigorous than at
\ Ourlana stations Nos. 1
and 2.
Subsoil (12 14 inches)
FOUGALA, STATION NO. 1.
Surface crust
Surface soil (1-12 inches)
Subsoil (12-30 inches)
Subsoil (30-48 inches)
Soil (1-4 feet) . . .
FOUGALA, STATION NO. 2.
Surface foot
Subsoil (12-30 inches) 1
Subsoil (30-48 inches) . . .
Hardpan (48-50 inches)
Soil (1-4 feet)
FOUGALA, STATION NO. 3.
Surface foot
Subsoil (12-26 inches)
Hardpan (26-28 inches)
Soil (1-4 feet) . ..
CHEGGA, STATION NO. ].
Surface foot
Subsoil at 3 feet
Soil (1-4 feet)
CHEGGA, STATION NO. 2.
Surface foot
CHEGGA, STATION NO. 3.
Subsoil (4-6 feet)
OURLANA, STATION NO. 1.
Surface foot
Subsoil (12-24 inches)
Subsoil (24-36 inches) . .
Subsoil (36-48 inches)
Soil (1-4 feet)
OURLANA, STATION NO. 2.
Surface foot
Subsoil (30-34 inches)
Soil (1-4 feet)
OURLANA, STATION NO. 3.
Surface foot
Subsoil (12-26 inches)
Subsoil (26-30 inches)
Soil (1 4 feet)
ARTESIAN WATER.
CHEGGA.
Well at date plantation
0. 4243
0. 2082
0.0046
0.0030
0.6401
OURLANA.
Puits Desveaux
.2972
.3311
.0040
.0030
.6353
ANALYSES OF SAHABAN SOILS.
97
PREVIOUS AND SUBSEQUENT ANALYSES OP ALKALINE SOILS FROM THE SAHARA.
Two analyses of soil from the vicinity of Ourlana are reported by Holland. These
analyses were not complete, for all the more soluble constituents are lumped as salt,
which is here synonymous with alkali. The vegetable soil of a new garden (see analy-
sis No. 23, in Table 34) at Tala em Mouidi, very near Ourlana (Saharan formation) ,
showed 6.8 per cent of alkali. Another soil (No. 24, Table 34) was from Mazer,
about a mile northeast of Ourlana. Here the sample was of washed soil of a salt flat
not yet under culture; it contained 3.4 per cent of alkali. The same work reports 7
per cent of alkali in the vegetable soil (No. 21, Table 34) of a garden at Tougourt, 20
miles south of Ourlana, and at Coudiat el Koda, very near Tougourt, no less than
29.5 per cent of the estimated weight of the soil (No. 19, Table 34) of an alkali flat
was composed of alkali (see analysis No. 19). The same soil (No. 20, Table 34)
washed for two years and put under culture contained only 0.5 per cent of alkali.
TABLE 34. Composition (in percentage by weight) of Saharan soils, collected by Holland. 1
Num-
ber of
analy-
sis.
Nature of sample.
Silica
or
quartz
sand.
Clay.
Per-
oxid
of
iron.
Car-
bonate
of
lime.
Car-
bonate
of
mag-
nesia.
Calci-
um
sul-
phate.
Salt.'
Water
and
organic
matter.
Total.
14
19
20
Vegetable soil of a garden
at El Golea (quaternary) . .
Soil of Sebkha (alkaline flat)
at Coudiat el Koda, near
Tougourt (quaternary) ...
Same soil as No. 19 washed
for 2 years and put under
culture
39.0
50.0
70
6.0
5.0
9
3.0
1.0
1 3
43.0
5.0
7
7.0
2.0
1
0.5
5.0
5
0.6
29.5
5
0.3
2.0
6
99.4
99.5
99 8
21
23
24
Vegetable soil of a garden at
Tougourt (quaternary)
Vegetable soil of a new gar-
den at Tala em Mouidi
(Saharan formation)
Washed soil of Sebkha (salt
flat) not yet under culture
at Mazer (modern)
48.0
11.8
30
6.0
55.5
26
2.0
1.3
3
9.0
8.0
20
0.7
1.2
22.0
8.0
15
7.0
6.8
3 4
5.0
7.0
5
99.7
99.6
99 7
16
Soluble portion (84.91 per
cent) of Saline incrusta-
tion of Sebkha at El Golea
(modern)
.56
2.95
95 16
1 69
100 26
1 Holland, G6ologie du Sahara, analyses by Ecole des Mines, Paris.
2 All the readily soluble salts occurring in these samples are lumped as salt, which is here equivalent
to alkali.
None of the soils analyzed for Holland was selected with any reference to date cul-
ture, and it is only from the samples secured by the writer and analyzed by the
Bureau of Soils, which have been described above, that any adequate idea can be
formed of the ability of the date palms to resist alkali. This power to withstand
alkali is one of the most striking among the life-history factors of this tree, since, in
this respect, it exceeds all other cultivated plants except possibly the cocoanut palm,
which latter is not killed by sea water containing 3.4 per cent of salts in solution. 6
Mr. O. F. Cook informs the writer that on Cape Mesurado, in Liberia, a Phoenix,
perhaps P. redinata, grows on the sea beach nearer to the surf than any other upright
vegetation, among the stunted shrubs killed back by the salt spray. The fruit of
this palm, though of inferior quality, is eaten by the natives. Hybrids should be
Holland, Georges. Geologic du Sahara.
& Ehrenberg and Hempricht report that on the island of Farsan, in the Red Sea,
date palms grow directly out of the crevices in the coral rock, of which the whole
island is composed, and although said to be irrigated from springs it may be found
that the trees are subject to occasional inundation by sea water,
13529 No. 5304 7
98
THE DATE PALM.
made between this and the common date palm, in the hope of securing alkali-resistant
date palms able to mature fruit near the sea in California.
Through the courtesy of Mr. Thomas H. Means, of the Bureau of Soils, the author
is enabled to present the results of the analyses of soils from date-palm plantations of
the Oued Rirh country in southern Algeria secured during the trip he and Mr. Thomas
H. Kearney made in 1902 for the Office of Seed and Plant Introduction and Distribu-
tion. These soil samples, which were collected after the above pages were writ-
ten, were obtained in the same region as those secured by the writer two years
previously, and amply confirm the writer's conclusions as to the extreme resistance
of the date palm to alkali. Mr. Means' s tabulation is as follows:
TABLE 35. Resistance of date palms to alkali at four stations in the Oued Rirh country in
the Sahara Desert in Algeria.
Chemical analysis.
Estimat-
Electro-
ed total
Location.
Condition of palms.
Depth
of
sample.
lytic de-
termina-
tions of
total
Total
salts.
Gyp-
sum.
Harm-
ful.
alkali in
soil mois-
ture(gyp-
sum put
salts.
at 0.06 per
cent).
Inches.
M'raier
Good
0-12
4.5
Do
do
12-36
1 4
Do
do
36-60
.5
Ourlana
Good* 13 years old
0-12
bi 5
4.36
3 45
0.71
0.76
Do
do
12-36
b.36
4.02
2.20
.82
.88
Do
Good* 20 years old
0-12
4.77
3.79
.98
1.03
Do
do
12-36
4.46
3.89
.57
.62
Do
do
36-54
4.63
3.53
1.10
1.15
Do
do
(1-4 ft )
.86
Ourir
Fair
0-12
6.99
2.38
4.61
4.66
Do
do
12-26
4.82
3.90
.92
.97
This column has been added to Mr. Means's table, and shows the amount of alkali, counting cal-
cium sulphate at 0.05 per cent in accordance with the method outlined on p. 74. These sums may
be compared with the analyses reported on the preceding pages and with the alkali content of soils
determined by the electric method.
&In regard to the seeming discordance between the results of the determination of the amount of
alkali by the electrical and chemical methods, Mr. Means writes as follows: " The apparent discrep-
ancy between the total solids as determined by the bridge and by chemical analysis in the samples
collected from 13-y<
laboratory was colle
collected from 13-year-old palms at Ourlana is due to error in sampling, for the sample sent to the
lected from a different hole from the sample determined by the bridge."
The amount of harmful alkali is very high in these soils, higher in fact than in any
of the soils collected by the writer except at Chegga, Station No. 1, and Fougala,
Station No. 1. These newest analyses demonstrate anew the remarkable alkali
resistance of this wonderM palm and show that it is perhaps more resistant than
the writer's soil samples seemed to indicate, and make his estimates of its probable
resistance conservative, to say the least.
DRAINAGE WATER FROM ALKALINE SOILS USED TO IRRIGATE DATE PALMS IN THE SAHARA.
It is a remarkable fact, showing the high resistance of the date palin
to alkali, that drainage water is used to irrigate date palms even in the
Oued Rirh region, where the artesian water is strongly brackish as it
flows from the well, and where in addition it must seep through the
very alkaline soil before reaching the drainage ditches. Such palms
are said to be less vigorous and to yield less fruit. There are several
date plantations in the oasis of Tozeur, in the Tunisian Sahara, which
are irrigated exclusively by water from the drainage ditches of gardens
See Yearbook of the Department of Agriculture, 1902, p. 573.
ALKALI CONDITIONS IN SALT KIVEB VALLEY. 99
situated on higher land." These plantations are so low that drainage
is impossible, and naturally the growth is poorer and the yield lower
than in better situations, but it is remarkable that even date palms
should be able to grow at all in such situations.
ALKALI CONDITIONS IN RELATION TO DATE CULTURE IN THE SALT
RIYER VALLEY, ARIZONA.
A recent soil survey of the Salt River Valley region made by Thos. H.
Means 6 shows that there are considerable areas, perhaps 1 per cent of
the land in the valley, where the amount of alkali in the soil is from
0.25 to 0.50 per cent, or enough to be dangerous for most crop plants,
and much more, perhaps 5 per cent of the land, contains over 0.5 per
cent where none but alkali-resistant crops can grow. Most of these
alkali spots are caused by the rise of the ground water in the lowest
levels, as a result of irrigation, until it comes so near the surface that
moisture reaches the surface and alkali is carried up from the subsoil
by the capillary currents of water. Such ground water has leached
from higher levels and is often charged with considerable amounts of
alkali.
The water used to irrigate the Salt River Valley is diverted from
the Salt River and conducted to the fields in open ditches. The river
is low during summer and the water often contains a considerable
amount of harmful alkali in solution. Prof. R. H. Forbes, who made
a study of the water of the Salt River from August 1, 1899, to August
4, 1900, finds that from Jane 1 to August 4, 1900, the average content
of soluble salts was 139 parts per 100,000, of which only 8.2 parts per
100,000 consisted of the harmless gypsum, leaving 130.8 parts per
100,000, or 0.13 per cent of harmful alkali. Professor Forbes remarks
that "it is to be remembered that this year (1900) was exceptionally
dry, and the waters'were consequently concentrated for a longer than
usual time. Nevertheless, for a considerable portion of each year
these waters are low and salty in character, and it remains true that
their use (which is unavoidable) must be attended with remedial care." c
Professor Forbes considers it probable that with the prevailing agri-
cultural practice of Arizona the use of irrigating water containing
100 parts of soluble salt per 100,000 is likely in a few years to cause
harmful accumulations of alkali. In view of this danger the great
value of. the date palm is obvious, since it can support very much more
alkali than is sufficient to kill other crop plants.
Masselot F. Les dattiers des oasis du Djerid. In Bui. de la Direction de 1' Agric.
et du Commerce, Re"gence de Tunis, Vol. 6, No. 19, April, 1901, p. 132.
& Means, Thos. H. Soil Survey in Salt River Valley, Arizona, Field Operations
of the Division of Soils, U. S. Department of Agriculture, 1900, pp. 287-332.
Forbes, R. H. Bui. 44, Arizona Agricultural Experiment Station, Tucson, 1902,
p. 166.
100 THE DATE PALM.
As was noted on page 86, water as alkaline as this is without any
direct effect on the date palm and could be injurious only by leading
to the accumulation of alkali in badly drained soils after many years
of heavy irrigation.
A sample of surface crust from an alkaline spot south of Tempe,
Ariz. (sec. 3, T. 1 S., R. 4 E.), near where the Cooperative Date Garden
(Pis. XXI, XXII, and fig. 6, p. 36) is located, shows the following
relative amounts of alkali soluble in excess of water (50 grams of soil
to 1,000 grams of water), which may be compared with the analyses
of crusts from the Sahara and from the Sal ton Basin (p. 134) :
TABLE 36. Percentage composition of alkali (soluble in excess of water) in surf ace crust
from near Tempe, Ariz. a
Calcium sulphate 1. 56
Magnesium sulphate 3. 04
Sodium sulphate 8. 98
Sodium chlorid J 59. 72
Potassium chlorid 12. 18
Sodium carbonate 4. 14
Sodium bicarbonate . . .10. 38
Total per cent of weight of soil 2. 56
The surface soil (1 to 12 inches in depth) from the same station
shows the following amounts of alkali stated in per cents of the weight
of the soil:
TABLE 37. Per cent of alkali in surface soil from Tempe, Ariz. &
Calcium sulphate 0. 06
Magnesium sulphate 06
Sodium sulphate 22
Sodium chlorid 1. 53
Potassium chlorid -. 23
Sodium carbonate 06
Sodium bicarbonate . . .32
Total 2. 48
It must be remembered that in. the Cooperative Date Garden at
Tempe the roots doubtless reach a subsoil containing much less than
this amount of alkali. Most of the alkali spots in the Salt River
Valley can be planted profitably to date palms if care be taken in irri-
gating (see chapter on drainage, p. 50). Near the date garden alfalfa
was killed by the rise of alkali a few years ago, and even pear trees
showed evident signs of distress, while a date palm growing alongside
was entirely unaffected by the alkali.
Analyses quoted from Thos. H. Means, Field Operations of the Bureau of Soils,
Second Report, 1900, p. 320.
& Calculated from an analysis reported by Means, 1. c., p. 320.
ALKALI CONDITIONS IN THE &ALTON BASIN.-' 101
It should be noted that the alkali occurring NUM-IHY parts 'df the Salt
River Valley, represented by this sample, is of a different type from
that found in the Algerian Sahara and in the Salton Basin, California.
In the last-named regions the alkali is of the "white" kind and con-
tains only very small percentages of carbonates or bicarbonates. In
the Salt River Valley sample, on the contrary, the alkali is of the
so-called "black" sort, and contains an appreciable amount of the
highly poisonous sodium carbonate, which is much more injurious to
most plants than is "white alkali." Black alkali is intensely alkaline
in reaction, a and because of this reaction is highly corrosive to the
roots of plants. It also has the property of dissolving the humus of
the soil, which causes the formation of black crusts and of black spots
in the fields where this type of alkali is abundant; whence the name.
From the thrifty growth of the date palms in the Cooperative Date
Garden at Tempe, Ariz., in soils approximating the above sample in
the amount and nature of their alkali content, it is probable that the
date palm is able to resist small quantities of black alkali. Further
researches are, however, needful to settle this point. (See p. 120.)
ALKALI CONDITIONS IN RELATION TO DATE CULTURE IN THE SALTON
BASIN, CALIFORNIA.
GEOGRAPHY AND GEOLOGY OF THE SALTON BASIN.
The Salton Basin, or Colorado Desert, (see PL IV, p. 122, fig. 10,
p. 102, and PL XVIII, fig. I), 6 is a basin the center of which is far
below sea level (some 263 feet below at Salton). It is surrounded by
mountains on three sides, and is limited on the south by sedimentary
deposits of the delta of the Colorado River which have piled up con-
siderably above the sea level. The high San Jacinto Mountains on
the west effectually protect the basin from the cold and humid winds
from the Pacific Ocean, while the still higher San Bernardino Moun :
tains form a barrier on the north that stops the cold winds that sweep
across the Mohave Desert; on the east, San Bernardino and the lower
Chocolate Mountains limit the basin.
That part of the Salton Basin which lies below sea level was covered
until comparatively recent times by the Gulf of California, which then
extended much farther north than now. The Colorado River, which
then flowed into the gulf near where Yuma is now situated, brought
down at flood times an enormous mass of sediment, which gradually
Alkali, in spite of its name, is often composed of neutral salts, such as sulphates
and chlorids, and has in consequence no pronounced alkaline reaction. (See p. 72.)
& See also Pis. LXXXVII. to XCV, Means and Holmes, Soil Survey around Impe-
rial, Cal., in Field Operations of the Bureau of Soils, Third Report, 1901; also
Pis. XXIII to XXVI, Coville and MacDougal, Desert Laboratory of the Carnegie
Institution, Publication No. 6, Carnegie Institution of Washington, November, 1903.
102
THE DATE PALM.
116'
115
35 10 o 10 zo so 40
EXPLANATION
WZm AREA SHOWN IN PLATE III
LOWLANDS IN COL.RIV.VALLEYi
32
116
115'
FIG. 10. Sketch map showing the Salton Basin and the easily irrigable lowlands in the Colorado
River Valley in Nevada, Arizona, and California. The area inclosed by the dotted line is below sea
level. Based chiefly on maps of Lieutenant Ives and of the International Boundary Commission.
ORIGIN OF THE S ALTON BASIN. 103
built a bar across the narrow gulf and cut off the upper portion, now
the Sal ton Basin, from the sea. a
Barrows says: 6
All this took place in very recent times. The Coahuila Indians, who to-day inhabit
the upper end of the valley, have a distinct apd credible tradition of the drying up
of this lake and of the occasional sudden return of its waters, and the Dieguenos, who
lived at a time when the supply of water along the central portion of the valley was
probably much greater than at present, raised on the naturally irrigated soil abun-
dant crops of maize, melons, and beans. But slowly the valley was abandoned to
aridity. Almost unvisited by rainfall, except about the edge of the mountains, the
loss of the river left it cruelly dry. Low, and inclosed between heat-reflecting ranges
that shut off the breezes of the ocean, it gained a temperature which is one of the
highest on the globe. The windstorms that rage up the valley from the southeast
have drifted great dunes of sand over certain portions, and much of the country
never reached by the deposits of the lake is as black, stony, and repulsive as erup-
tive rock formations in the desert can be. Apparently about the middle of the first
half of the century the overflow from the Colorado was largely checked and not
resumed to any extent until the year 1849. The Indians, who had lived in plenty
along the central valley, were driven by the drought forever from their homes.
During the high flood of the Colorado River in June and July the
water breaks through its banks near Algodones, in Mexico, a few
miles below Yuma, and flows westward through an old channel for
some thirty miles; then, turning north into the United States, it flows
through the Salton River to Salton Lake, filling up Mesquite Lake
on the way. Most of the stream, however, goes on to Lake Jululu,
or Volcano Lake, from which the New River flows northward to Sal-
ton Lake, and the Hardy River southward to the Gulf of California
(see fig. 10). The Salton and New rivers flow only during the high-
est floods, but the Hardy River flows all the year, being fed by the
Rio Padrones.
The Maquata Basin, a region similar to the Salton Basin, and, like
it, lying below sea level, lies to the west of the Cocopah Mountains in
Mexico. It is usually a waterless desert, but, at times of very high
flood in the Hardy River, water flows around the mountain range,
creating the Laguna Maquata c (see fig. 10) in the center of the basin.
This is probably the only region in Mexico which, when irrigated,
will be suitable for the culture of the best sorts of dates.
Some students of this region believe that an upheaval of the region covered by
the delta aided in cutting off Salton Basin from the Gulf of California. The occur-
rence of mud volcanoes and of extinct craters, such as the Sierra Prieta, lends
strength to the view that the piling up of such enormous masses of sediment has
induced geologic changes. The old beach lines of the Salton Basin are, however,
still approximately at sea level, which would go to show that there has been but
slight change in the level of the region as a whole since it was cut off from the sea.
(See Barrows, David P., The Colorado Desert, in National Geographic Magazine, Vol.
XI, No. 9, September, 1900, p. 340.)
&L. c., p. 341.
c Barrows, 1. c., p. 344.
104 THE DATE PALM.
The greater part of the Salton Basin is as level as a floor and almost
as destitute of vegetation (see PI. XVIII, fig. 1), which renders it an
exceptionally favorable region to put under irrigation, since in most
places no leveling is required and very low dikes serve to retain the
water.
The geographical position of Salton Basin is indicated by figure 10,
its general character is shown in Plate XVIII, figure 1, and a detailed
soil map, showing t}^pes of soil and the amount of alkali present, is
given in Plate III, page 106. The location of the area shown in Plate
III is indicated by the ruled space in figure 10, page 102.
Many schemes have been broached for the irrigation of the Salton
Basin since it was first surveyed in 1854. Since 1891 Mr. C. R. Rock-
wood, of Los Angeles, Cal., has been making surve} T s and persistently
endeavoring to interest capital in irrigating this region. His efforts
have resulted in the formation of a company which in 1901 carried
the first water into the lower part of the Salton Basin. a Land and
irrigation companies formed at the same time and, working in cooper-
ation with the company mentioned, pushed energetically the sale and
development of the land irrigated by the water, and now in 1903 some
100,000 acres are under irrigation and it is planned to extend the canals
so as ultimately to irrigate most of the basin below the sea level, some
500,000 acres in all.
The main diversion works are at Han Ion's Heading, some 7-J- miles
below Yuma, whence the water is conducted about 8 miles to the
channel of the Salton River, which is used to carry the water 60
miles to the northwest, where at the international boundary line it is
turned into a 60-foot canal with a capacity of 5,000 second-feet,
intended to irrigate all the lands lying between the Salton and New
rivers. After entering the United States for a short distance this
large canal is divided into two 30-foot canals running side by side, the
object being to use one while the other is being cleaned. The courses
of the lateral canals are shown in the map on Plate III. Other main
canals are planned to conduct the water from the Salton channel to
irrigate land in Mexico as well as lands in the Salton Basin in Cal-
ifornia lying east of Salton River and west of New River b (see
figure 10, p, 102).
WATER SUPPLY OF THE SALTON BASIN.
The greater part of the Salton Basin can be watered from the Colo-
rado River, and a large area in the basin, from Calexico, on the Mexi-
can boundary, to Imperial, Brawley, and northward, is now irrigated
Means, Thos. H., and Holmes, J. Garnett. Soil Survey around Imperial, Cal.
In Field Operations of the Bureau of Soils, U. S. Department of Agriculture, Third
Report, 1901, p. 588.
& Means and Holmes, Soil Survey around Imperial, Cal., Field Operations of the
Bureau of Soils, U. S. Department of Agriculture, Third Report, 1901, pp. 588, 589.
WATER SUPPLY OF THE S ALTON BASIN. 105
by means of water conducted from near Yuma, as above described.
Fortunately, the Colorado River water is of remarkably good quality,
although this stream flows for hundreds of miles through arid regions
and many of its tributaries drain highly alkaline deserts. An exten-
sive set of analyses was made by Prof. R. H. Forbes for the period
from January 10, 1900, to January 24, 1901," during which time the
content in soluble salt of the river water at Yuma varied from 21 to
1 25 parts per 100,000, or from 0. 021 to 0. 125 per cent. During the low
stages of the river in winter, early spring, and late in summer, the
alkali content runs about 90 parts per 100,000. For two months (from
May 25 to July 27, in 1900), during the flood caused by the melting of
the snows of the Rocky Mountains, less than 27 parts of soluble salt
in 100,000 were observed. On the other hand, during a smaller sud-
den rise in October, due to torrential downpours on the Arizona water-
shed, the alkali content rose markedly, averaging 105 parts per 100,000
from September 26 to November 19. This decided increase in the
soluble salt content of the water was doubtless occasioned by the wash-
ing of salts out of the desert soil into the Arizona rivers and its subse-
quent drainage into the Colorado River. During the year 1900 the
Colorado River water contained less than 100 parts of salts per 100,000
of water during 315 days and more than 100 parts per 100,000 during
only 50 days.
During the growing and fruiting season of the date palm, from
April 15 to September 15, inclusive, when four-fifths of the water
needful for the whole 3^ear,must be applied, the soluble salt content
ranges from 0.021 to 0.068 per cent, or from 21 to 68 parts in 100,000
of water; while for two months during the flood, when water is most
abundant for irrigation purposes and consequently most easily spared
for washing alkali out of the soil, the alkali content is only about 27
parts per 100,000, or 0.027 per cent.
A considerable part of the soluble salts held in solution consists of
harmless (if not beneficial) gypsum, which varies but slightly during
the year, making up from 5.6 to 8.6 parts per 100,000, which would
reduce the harmful alkali content during the summer months to about
14 to 60 parts per 100,000, and to 20 parts per 100,000 during the two
months of flood in May, June, and July. Such small amounts of
alkali in irrigation water are without harmful influence.
The relatively high purity of the Colorado River water is shown
best by a comparison with that used to irrigate the flourishing date
gardens of the Sahara. At Biskra the amount of soluble salt varies
from 75 to 235 parts per 100,000, and is highest in summer, when
the palms need most water. At Chegga, Algeria, the soluble salt
Forbes, B. H. The River Irrigating Waters of Arizona Their Character and
Effects. Bui. No. 44, Arizona Agricultural Experiment Station, Tucson, 1902, p. 202.
106 THE DATE PALM.
content of the artesian water is no less than 640 parts per 100,000, and
after subtracting gypsum there remain 434 parts per 100,000 of harmful
alkali 0.434 per cent, or 250 grains to the gallon. At Ourlana,
Algeria, very extensive and flourishing plantations are irrigated from
a flowing artesian well (Puits Desveaux), where the water contains 635
parts per 100,000 of soluble salt and 403 parts per 100,000 of harmful
alkali.
The Colorado River water is better than that used to irrigate the
famous Salt River Valley of Arizona, and has the advantage of having
the lowest alkali content in summer, whereas just the reverse is true
of the Salt River water (see p. 99).
The water of the Colorado River carries, both in solution and in
suspension as tine silt, fertilizing materials of considerable value, con-
sisting principally of potash, nitrogen, and phosphoric acid. The
soils of the Salton Basin are at present so rich that they do not need
the fertilizers thus carried to the land by the irrigating water, but
such fertilizing substances deposited by the water will serve to keep
up the fertility in the future even under heavy cropping. Even
now the phosphoric acid brought by the Colorado River water (see
p. 114) is doubtless decidedly beneficial to the soils of the Salton Basin,
which contain but very small amounts of this very necessary plant food.
SOIL CONDITIONS IN THE SALTON BASIN.
The soil conditions existing in the greater part of the Salton Basin
are shown by Means and Holmes, of the Bureau of Soils, a who made
surveys in 1901 covering some 108,100 acres lying between the New
and the Salton rivers (fig. 10 and PI. Ill), comprising the larger part
of the basin as yet put under irrigation. This area is shown on
Plate III. The same classes of soils and the same general condition of
alkalinity prevail over the greater part of the Salton Basin. 5
In the portion of the basin surveyed by Means and Holmes five
types of soils were recognized. The areas occupied by these types
are shown in Table 38.
Circular 9, Bureau of Soils, January, 1902, and Field Operations of the Bureau of
Soils, U. S. Department of Agriculture, 1901, pp. 587-606, map 29.
& The University of California also investigated the soil conditions in the Salton
Basin, and in February, 1902, published a valuable report on this region (Snow,
Frank J., Hilgard, E. W., and Shaw, G. W., Lands of the Colorado Delta in the
Salton Basin, Bui. 140, Cal. Agr. Exp. Sta., pp. 51, with supplement by Joseph Burtt
Davy, The Native Vegetation and Crops of the Colorado Delta of the Salton Basin,
April, 1902, pp. 8) .
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agricultur
PLATE III.
EXPLANATION.
Suits survewd b\- Burc/iu <>!
H CO.M.V. Contour In trnn I H) Hrrr .
MAP SHOWING DISTRIBUTION OF SOIL TYPES AND OF ALKALI
INTHE IMPERIAL AREA, IN!HE SALTON BASIN, CAL.
SOILS IN THE SALTON BASIN. 107
TABLE 38. Areas of different soils Mirwyed in the Salton Basin around Imperial, Cal.
Soil type.
Area.
Per cent
of area
surveyed.
Dnnesand
Acres.
29 840
27 7
I ni perial sand
1 020
1
>3 710
21 9
Imperial loam
30 410
28
23 120
21 4
Total -- ' ...
108 100
100
The alkali content of the surveyed land is shown in Table 39.
TABLE 39. Alkali content of soils surveyed in Salton Basin around Imperial, Cal.
Alkali content.
Area.
Per cent
of area
surveyed.
Less than 9 per cent
Acres.
42 220
39 1
From 2 to 4 per cent
25 320
23 4
From 4 to 6 per cent
23 040
21 3
From 6 to 1 per cent
5 220
4 8
From 1 to 3 per cent
5 670
6 3
6 630
6 1
Dunesand consists of reddish-brown sand, rather rotten, and often
mixed with small particles of flocculated soil. It is blown by the wind
into small dunes, usually crescent-shaped and 2 to 10 feet high. The
dunes are underlain by the heavier soils of the basin. This soil is
mostly free from alkali, but the land is not now occupied for agricul-
tural purposes because of the heavy expense necessary to level it to ren-
der it fit for irrigation. This expense is variously estimated at from
$20 to $30 an acre, and in view of the preference of the date palm for
sandy soils, it may prove in future a profitable investment to level
such land and plant it to the choice varieties of date palms. This dune-
sand area, as may be seen from the maps, is of considerable extent.
The small area of level Imperial sand is also free from harmful
quantities of alkali and would be very useful for date culture. The
anlount of such land is small, however, and it will probably be used
for truck crops sensitive to alkali.
The Imperial sandy loam soil is formed by the coarsest particles of the Colorado
River deposit mixed with wind-blown sand. The sandy loam extends to a depth of
3 feet and is underlain by a loam or heavy loam. This soil will take water readily, and
where level and free from alkali is adapted to cultivated crops or alfalfa. Some of
the best and some of the worst lands of the valley are composed of this type.
The Imperial sandy loam occupies over one-fifth of the surveyed
area in the Salton Basin and is probably the soil on which the date
palm will succeed best, as it is on such land that it grows best in the
Sahara.
Means and Holmes. Field Operations of the Bureau of Soils, U. S. Department
of Agriculture, 1901, p. 594.
108 THE DATE PALM.
About three-quarters of the area occupied by this type of soil con-
tains less than 0.6 per cent of alkali, which amount is absolutely with-
out harmful effect on the date palm. It will probably grow nearly as
well on an additional 10 per cent of the land even without drainage,
and could struggle along on 10 per cent more of the area, while if
drainage were provided doubtless the whole area of sandy loam could
be planted to date palms.
The Imperial loam soil has a smooth surface as level as a floor and
almost devoid of vegetation.
It has the peculiar slick, shiny appearance often seen in localities where water has
recently stood. It is the direct sediment of the Colorado River, which was deposited
in strata when the area was under water. These strata are from 0.01 inch to 2 or 3
inches thick, very much resembling shale; in fact, to all external appearances being
exactly similar. When water is applied, however, the soil softens up and is a red-
dish, sticky loam, a little heavier than a silt loam. It is from 4 to 6 feet deep, under-
lain by a clay or clay loam, and contains considerable organic matter, including an
abundance of nitrogen and potash. When free from alkali it is well adapted to the
growing of wheat, barley, and alfalfa. a
The Imperial loam is much like the heavj 7 soils in the oases at the
northern edge of the Sahara, in Algeria, and is well adapted to the
date palm if properly irrigated to prevent its becoming too dry and
if kept in a proper state of tilth to prevent packing. This soil is very
alkaline in the region surveyed in the Salton Basin, but about 60 per
cent of the area covered by this soil has less than 0.6 per cent of alkali,
and an additional 10 per cent will support the date palm nearly as well,
making TO per cent of the land where this plant will be unhampered
by alkali. The date can grow, though less vigorously, on an addi-
tional 15 per cent of the area, though it may not fruit Well unless
drainage be provided and some of the alkali washed out.
The Imperial clay soil (PI. XVIII, fig. 1) is found as a surface soil
or as subsoil at greater or less depth throughout the surveyed area.
It is usually comparatively level, although in some places small hummocks have
been blown up on its surface. It is this soil that surrounds both the towns of Calexico
and Imperial, the only difference in the soils of the two districts being in the alkali
content. The soil has been formed by the deposition of the finest sediment of "the
Colorado River, and is stratified in the same way as the loam. It is a heavy, sticky,
plastic soil, very much resembling the clay subsoil found in the Mississippi River
Delta. When dry and in its natural state, it exists in hard cakes and lumps, which
may be cut with a knife and are susceptible of taking a high polish. When wet, the
lumps are very plastic and sticky, making a soil which is very refractory and difficult
to cultivate, Upon drying, the soil becomes very hard and cracked. Sorghum and
millet were grown this year on several hundred acres of this land in the vicinity of
Calexico, and produced good crops. The sorghum, however, was the best, the yield
being 6 or 8 tons to the acre.
Cultivation of this clay soil will be very difficult. A similar soil is found in the
Salt River Valley as a phase of the Glendale loess, and is locally known as "slick-
's Means and Holmes. Field Operations of the Bureau of Soils, U. S. Department
of Agriculture, 1901, p. 595.
SOILS IN THE S ALTON BASIN. 109
ens." The farmers of that neighborhood have considerable difficulty in managing
this soil, and it is not as refractory as much of the Imperial clay. Either annual
crops or crops which can be cultivated throughout the growing season are productive
of best results on this soil, for the heavy and hard crusts need to be broken up and
thoroughly pulverized occasionally. Alfalfa does not do well on such soil, for the
crusts seem too hard arid the soil too dense and impenetrable to permit the constant
extension of the fine rootlets so essential to permanency in an alfalfa field. Deep
plowing and thorough cultivation will in a few years greatly improve this soil."
Practically none of the heavy clay soil is free from alkali, but some
45 per cent of this land in the surveyed area carries less than 0.4 per
cent of alkali, 6 and about 25 per cent more of the area occupied by
Imperial clay has from 0.4 to 0.6 per cent of alkali, where the date
will succeed as well, making some 70 per cent of this soil available for
the most remunerative date culture. The date palm can grow, but will
fruit less on 7.5 per cent more of the clay land even without drainage,
making in all about 77.5 per cent of this soil that is immediately avail-
able for date culture. The date can struggle along even without
artificial drainage on, perhaps, 75 per cent more of the area.
The observations of Mr. D. G. Fairchild near Bassorah, on the Shat-
el-Arab River, at the head of the Persian Gulf, show that these great
date plantations, the most extensive in the world, are on u as pure an
adobe as the clay of a brickyard," and indicate the probability that
dates may be grown successfully on any heavy soils, provided the soils
be adequately drained and aerated.
In the Bassorah date region the soil is automatically watered, drained,
and aerated by a system of ditches which fill from the river at high
tide and drain out again at low tide.
In the Salton Basin and elsewhere in the United States it is prob-
able that drainage ditches or tile drains will be necessary to permit the
proper utilization of the heaviest clay soils.
Messrs. Means and Holmes say: "Of the lands which are level
enough to permit profitable irrigation 17 per cent have to 0.2 per
cent of alkali, and are at present safe for cultivation to all ordinary
crops; 32 per cent have 0.2 to 0.4 per cent of alkali, which is risk} r for
ordinary crops; the remaining 51 per cent are too alkaline to be taken
up for any but alkali-resistant crops." That is to say, only 49 per
cent of the irrigable land in the surveyed area of the Salton Basin is
suitable for growing ordinary crops, whereas 76 per cent is available
for date culture.
Means and Holmes. Field Operations of the Bureau of Soils, U. S. Department of
Agriculture, 1901, pp. 595, 596.
* In soils of this nature, having a very fine texture and consequently a high water
capacity, a given percentage of alkali is not so injurious as in a sandy soil of low
water capacity, for the reason that the alkali forms a more dilute solution in the soils
which hold more water. (See p. 75. )
c Fairchild, D. G. Persian Gulf Dates and Their Introduction into America.
Bui. No. 54, Bureau of Plant Industry, U. S. Department of Agriculture, 1903.
110
THE DATE PALM.
To summarize, the date palm can grow on the following- areas in
the surveyed region without any especial provision being made for
drainage:
TABLE 40. Area of lands in the surveyed portion of the Salton Basin suitable for date
culture.
Kind of soil.
Total
irrigable
area.
Area where
date palms
will be
unaffected
by alkali.
Area where
date palms
will grow
and fruit
without
artificial
drainage,
but less
vigorously.
Area where
date palms
will be able
to struggle
along but
not to fruit
well unless
artificial
drainage is
provided.
Per cent of
total irriga-
ble area im-
mediately
available
for date
culture
without
artificial
drainage.
Additional
percentage
of total
irrigable
area where
date palms
can grow
but not
fruit well
without
drainage.
Imperial sand
Acres.
1,020
23, 710
30. 410
23,120
Acres.
1,020
17,800
18,300
16,200
Acres.
Acres.
100
85
70
77.5
Imperial sandy loam
2,400
3,000
1,800
2,300
4,500
1,800
10
15
7.5
Imperial loam
Imperial cl ny . .
Total. ..
78,260
52,320
7,200
9,800
76
12. f)
In all some 59,520 acres, or 76 per cent of the 78,000 acres of sur-
veyed land level enough to permit irrigation, is immediately available
for profitable date culture without artificial drainage, while the date
palm will grow on an additional 12.5 per cent of the land, though it
probably will not fruit well unless the soil is drained.
With proper drainage almost all the surveyed area except about
3,000 acres of clay soil could be rendered suitable for date culture by
washing out the alkali. Only 6 out of 156 borings made by Messrs.
Means and Holmes showed a percentage of alkali so high as to be
dangerous to the life of the date palm.
The immense importance of date culture for this region becomes at
once apparent. It is the only profitable culture that can be followed
on a quarter of the irrigable area too alkaline for other crops, while
the climatic, soil, and water conditions are here so favorable for the
date palm (see pp. 52 to 72) that it will pay to plant the choice sorts
even on the best lands where many other crops would succeed.
It becomes of the greatest importance to introduce the Deglet Noor
date into this region, where all the conditions combine to render its
culture profitable, and where at the same time it is necessary in order
to utilize a large part of the area already occupied and irrigated. a
a Very recently (March, 1904), since this bulletin was sent to the Printing Office,
the Department of Agriculture has established, in cooperation with the California
Experiment Station, an experimental date garden in the Salton Basin at Mecca, Cal.
[Mecca was called Walters until January, 1904, and is so shown on all old maps and
on fig. 10, p. 102.] At the same time a large number of offshoots of the best sorts of
date palms (including many of the Deglet Noor variety) were ordered from the prin-
cipal centers of date culture in the Algerian Sahara. In addition, several large Deglet
Noor palms are being transplanted bodily, with large balls of earth about the roots,
from Tempe, Ariz. , in order to test as soon as possible the ability of this variety to
fruit in the Salton Basin.
ALKALI CONDITIONS AT PALM CANYON.
Ill
In the northern part of the Salton Basin around Indio and Walters,
Cal., there are flowing artesian wells; in this and in many other
respects the conditions of the Oued Rirh region in the Sahara are
almost exactly reproduced. It is probable that date culture will prove
even more profitable here than in the Oued Rirh country, since the
summers are hotter in the Salton Basin, which will insure that the
Deglet Noor variety will mature its fruit completely every year. The
soils of this part of the Salton Basin have not yet been studied with
reference to their alkali content, but it is known that there are large
areas of land which could be irrigated by artesian wells where there
is so much alkali that the growing of ordinary crops is prevented. a
On such areas the culture of the date palm is likely to be the only
paying industry that can be followed.
ALKALI CONDITIONS AT PALM CANYON, IN THE FOOTHILLS BORDERING THE SALTON BASIN.
The California fan palm (Neowashingtonia filifera) grows wild in the
foothills surrounding the Salton Basin wherever the soil is sufficiently
moist. In some respects the fan palm is much like the date palm, for
it needs a constant supply of water at the roots, it delights in hot, dry
weather, and can resist a large amount of alkali. An old fan palm
produces in a good season from 50 to 200 pounds of fruit, according
to Dr. Welwood Murray. The fruit is very small, of a pleasant flavor,
and it is not unlike a miniature date. Natural groves of these palms
as they occur in the foothills to the north of Indio are shown on
Plate XIX, figures 3 and 4. 6
Dr. Welwood Murray has kindly collected a series of soil samples
in the groves at Palm Canyon, near Palm Springs, Cal. These
samples were analyzed through the kindness of Prof. Milton Whitney,
chief of the Bureau of Soils, and the results are given herewith, cal-
culated in the same way as for the soil samples from the Sahara.
TABLE 41. Per cent of alkali in soils in which California fan palms were growing at Palm
Canyon, California.
Sta-
tion.
Locality and depth.
Cal-
cium
sul-
phate.
Magne-
sium
sul-
phate.
Sodium
sul-
phate.
Sodium
chlo-
rid.
Potas-
sium
chlo-
rid.
Sodium
car-
bonate.
Sodium
bicar-
bonate.
Total
alkali.
Al
A2
B
C
D
Surface soil and crust, flow-
ing water near by.
0.02
05
1.09
078
12.88
2.98
.214
.127
0.113
.156
.014
0.09
0.26
.143
.116
17.45
.66
.60
.25
5.80
Subsoil, about 2 feet deep . . .
Subsoil, about 4 feet deep . . .
Subsoil, sample taken from
between roots of a full-
grown fan palm.
.04
.078
.227
.02
.266
4.52
.696
.088
Tr.
.212
Recently J. Garnett Holmes, of the Bureau of Soils, United States Department of
Agriculture, has surveyed this area, and his report will soon be published.
& See also Plates XXV and XXVI, in Coville and MacDougal, Desert Botanical
Laboratory of the Carnegie Institution. Plate XXVI in particular gives an excellent
idea of the appearance of the fan-palm oases as seen from a distance.
112
THE DATE PALM.
Sample D is the most interesting, as it shows the ability of the roots
of the fan palm to grow in enormously alkaline soil.
A recalculation of sample D in comparison with the surface soil of
Station No. 1 at Chegga, Algeria, the only sample obtained in the
Sahara with so high an alkaline content, is given herewith.
TABLE 42. Per cent of alkali in soil at Palm Canyon, California, and at Chegga, Algeria.
Locality and depth.
Sulphates.
Chlorids.
Bicarbo-
nates.
Total.
Palm Canyon, Station D, subsoil at 6 feet depth, full
of palm roots
4.806
0.784
0.212
5.80
5 11
63
08
5 82
No subsoil in the Sahara or from the Salton Basin as yet reported
is so alkaline as the subsoil from Palm Canyon. There are no roots
very near the surface,, where the amount of alkali is greatest, at
Chegga (or at the other Saharan stations), whereas the layer in ques-
tion in Palm Canyon is full of roots. Prof. R. H. Forbes a has called
attention to the occurrence of roots of the date palm at 6 feet in depth
in "very alkaline subsoil" in the Salt River Valley, Arizona, where
they were forcing their way into the calichi hardpan. The date palm
doubtless can stand as much alkali as the fan palm, and it is probable
that it would grow where the fan palm is now found wild.
The summer heat will doubtless be less than in the lower parts of
the Salton Basin, for these fan palms occur some 500 feet or more
above sea level. The winters are, on the other hand, warmer at such
altitudes, if there is a good drainage of cold air to lower levels (see
p. 61).
CHEMICAL COMPOSITION OP THE ALKALI OP THE SALTON BASIN.
An analysis of a mixture of eight surface crusts was reported in 1901
by Means and Holmes, which analysis is given below alongside that
of six surface crusts obtained in 1900 in the Algerian Sahara.
TABLE 43. Percentage composition of alkali in surface crusts from the Algerian Sahara
and from the Salton Basin, California.
Locality and sta-
tion.
Cal-
cium
sul-
phate.
Magne-
sium
sul-
phate.
Sodium
sul-
phate.
Magne-
sium
chlo-
rid.
Potas-
sium
chlo-
rid.
Sodium
chlo-
rid.
Sodium
bicar-
bonate.
Sodium
car-
bonate.
Sodium
nitrate.
Total
percent
weight
of soil.
Fougala No. 1 .
Fougala No. 4 .
Chegga No. 1.. .
Ourlana No. 1 .
Ourlana No. 2 .
Ourlana No. 3 .
M'raier
32.38
25.26
5.85
22.13
26.47
62.84
8.27
2.41
5.60
2.62
18.39
13.94
.66
21.86
8.35
36.71
86.49
3.08
2.69
.23
1.99
.60
1.32
1.74
53.06
28.77
4.47
51.78
55. 05
23.32
51.82
0.72
.97
.25
.80
.67
2.25
.48
17.33
15.03
64.13
14.52
18.43
5.14
56.32
0.09
4.91
3.27
9.61
15.83
Sahara, average
of 7 samples
Colorado Desert,
average of 8
sjvmplps
26.17
9.91
9.35
9.02
621.05
.33
b2.54
1.52
30.02
38.32
32.22
.88
9.59
ft. 013
8 91
a Arizona Experiment Station, llth Annual Report, p. 156.
b Wanting in some of the soils analyzed.
COMPOSITION OF ALKALI, SALTON BASIN.
113
The following table shows the composition of the alkali in a few
surface crusts and soils in the Salton Basin. The analyses are some
of those given by Means and Holmes. a
TABLE 44. Theoretical percentage composition of alkali in soil about Imperial, Col.
Soils,
"3
labo-
<K
rato-
Location.
~a~
4-
4-
JL
e',
g
g
Si
p.
-a
00
S
I'
%
S
B
U
1
o
W
3
&
6
9
fc
M
8
S
,1
M
fe
&
Inch.
Perct.
Perct.
Perct.
Perct.
Perct.
Perct.
Perct.
Perct.
Perct.
Perct.
Perct.
6308
NE. corner sec. 29,
T. 16 S., R. 14 E..
0~5
17. 42
9.16
2.62
27.72
2.41
37.77
14.62
5.70
6303
SW. corner sec. 13,
T. 17 S., R. 14 E..
0-5
18.36
9.95
17.38
6.23
59.10
0.89
5.19
1.26
6314
NE. corner sec. 36,
T. 14 S., R. 14 E..
0-3
15.05
3.97
34.02
6.56
48.76
.85
5.35
.49
6313
NE. corner sec. 29,
T. 14 S., R. 14 E..
0-3
15.30
3.69
46.60
8.44
33.08
.86
7.02
.31
6285
NE. corner sec. 29,
T. 16 S., R. 14 E..
0-36
.44
27.60
6.33
5.43
12.67
6.78
41.19
6286
Subsoil of 6285
36-7?
.59
26. 26
11.11
9.10
16.15
15.15
22.23
6279
NE. corner sec. 21,
T. 17 S., R. 14 E..
0-36
.93
32. 91
11.18
1.72
29.04
10.96
14.19
6298
NE. corner sec. 29,
T. 14 S., R. 14 E..
0-36
6.81
14.62
25.89
5.75
42.55
2.34
7.89
.96
6299
Subsoil of 6298
36-72
3.36
29.36
5.29
2.34
56.36
3.67
2.98
6295
NE. corner sec. 25,
T. 15 S., R. 14 E..
0.36
2 51
3.58
37.21
14.34
39.06
2.56
3 26
62%
Subsoil of 6295
36-72
1.82
4.28
15.17
3.40
66.39
5.38
5.38
The alkali of the Salton Basin is of the same type (" white alkali")
as that of the Sahara Desert in southern Algeria, since in both regions
a large excess of gypsum is present in almost all cases, which pre-
vents the formation, under ordinarily good conditions of culture and
drainage, of any dangerous amount of the very harmful alkaline car-
bonates. The Salton Basin samples differ considerably from those
from the Sahara in showing rather large percentages of sodium nitrate
in the surface crusts, which is entirely lacking in the surface crusts or
soils from the Sahara. However, only very small quantities of nitrates
occur below the surface crust in the soils of the Salton Basin, unless
the soils are so alkaline as to preclude all agriculture. The Salton
Basin soils often show considerable percentages of calcium chlorid,
wanting in Sahara soils. Salton Basin soils contain much larger per-
centages of potassium chlorid and sodium bicarbonate and a larger
proportion of chlorids and less sulphates than do the Sahara soils
examined
The Salton Basin alkali is slightly more dangerous to crops than that
of southern Algeria, because of the larger proportion of chlorids, and
because of the presence, in many cases, of considerable amounts of
sodium bicarbonate, which, if the land is watered excessively and
badly drained, may be converted into the very harmful sodium
carbonate.
Means and Holmes. Soil Survey around Imperial, Cal. Field Operations of the
Bureau of Soils, U. S. Department of Agriculture, Third Report, 1901, p. 601.
13529 No. 5304 8
114 THE DATE PALM.
FERTILITY OF THE SOILS OF THE SALTON BASIN.
On the other hand, the Salton Basin alkali contains a considerable
proportion of useful plant foods, especially sodium nitrate and -potas-
sium chlorid, which render the soils very fertile to any plant which,
like the date palm, can withstand a considerable percentage of alkali
in the soil. The Sahara soils are often mediocre or poor, and date
culture suffers in southern Algeria for the want of nitrogenous ferti-
lizers, wh'ich are very hard to supply at reasonable prices in such a
remote arid sparsely settled country. In the Salton Basin it may pay
to wash the surface crust down into the soil in order to carry the nitrate
of soda down within reach of the roots, in places where it is known that
there is little alkali in the subsoil. For instance, if a crust such as
No. 6308 of Table 44 (p. 113), containing 2.5 per cent of its weight of
nitrate of soda, occurred over such a soil as No. 6285, collected near
by, containing only 0.44 per cent of alkali to a depth of 3 feet, it is
probable that the crust might be washed down to the level of the roots
of the date palm without danger of their suffering from any excess of
alkali. Such an operation must, however, always be carried out with
caution, and is permissible only when it is known that the soil is rela-
tively free from alkali, and that the amount contained in the crust
would not suffice to raise it to the danger point for the date palm in
any soil stratum in which the roots ramify.
Considerable amounts of potassium chlorid exist in most of the
Salton Basin soils probably enough to suffice for the needs of vege-
tation for a long time to come. Besides being naturally so rich, these
lands will be improved by the deposition of silt a from the Colorado
River water used in irrigating and from the addition of the small
amounts of nitrates and potash contained in solution. (See p. 106.) In
particular the small amount of phosphates the water contains is likely
to prove very beneficial to the soils of the basin, naturally poor in this
element. Analyses of the Colorado River water made daily for a
period of seventeen months show that on the average it carries 13.8
pounds of phosphoric acid in an acre-foot of water or 55.2 pounds in
the 4 acre-feet probably needed annually by a date plantation when the
trees are full grown. What with the considerable supplies of nitrogen
and potash contained in the alkali of these soils and the phosphoric
acid brought by the river water, it is probable that the date palm will
show a most luxuriant growth and bear heavy crops in the Salton
Basin without any fertilizers being needed for many years, at least.
It must be kept in mind that much of the silt is deposited in the canal before it
reaches the land, and in consequence the fertilizing value of the water is not so great
as when it leaves the river. (See Means and Holmes, Field Operations of the Bureau
of Soils, U. S. Department of Agriculture, Third Report, 1901, p. 598. )
SUBSIDIAKY CULTURES ON ALKALINE SOILS. 115
SUBSIDIARY CULTURES TO FOLLOW IN CONNECTION WITH DATE PLANTA-
TIONS ON ALKALINE SOILS.
Although no other profitable crop plant can stand as much alkali as
the date palm, there are a number which can endure considerable
amounts of alkali and which could be set out on the less alkaline parts
of the tract to be planted or under the date palms after much of the
excess of salts had been washed out of the soil by several years' irri-
gation, accompanied by drainage. The grape, the olive, the pome-
granate, the jujube, and the fig are commonly grown in the partial
shade of the date palm in the Saharan oases. (See PL V, fig. 1,
and PI. XII.) All of these plants can endure more alkali than can
most fruit trees, though the almond and pear resist considerable
amounts. Barley is one of the crops that can stand much alkali, and
it is commonly grown in winter between the rows, especially of } r oung
date plantations. Sorghum is equally resistant. Asparagus is found
to do very well in the salty soils of the Oued Birh country, and it may
prove a profitable minor culture. Cotton is alkali-resistant in Egypt
and is grown in the oases in the interior of the Sahara.
Since a species of pistache, which could be used for stock on which
to graft the pistache of commerce, occurs in the northern Sahara,
where it is the only tree that grows wild, it is not impossible that this
choice nut may be grown to advantage on alkaline soils. Carobs can
stand the heat and dry air of the desert very well, yielding fruit valu-
able for horse and cattle food in place of grain, and are at the same
time very ornamental evergreen shade trees, suitable for street plant-
ing. The Casuarina, the Tamarix, and some of the acacias and Euca-
lypti are trees well adapted to endure desert climates. Among forage
plants the Australian saltbush deserves first mention, for it can endure
very large amounts of alkali. Sorghum is another useful forage plant
for such land. Saharan alfalfa will prove of great value for the less
alkaline soils those having 0.5 per cent of alkali or less. It is not
unreasonable to hope to find a whole series of crops which can endure
a considerable amount of alkali in the soil, and which will permit some
diversification of agriculture even on the most alkaline tracts that are
first put under culture by planting date palms.
LIMITS OF ALKALI RESISTANCE OF THE DATE PALM.
It is naturally of very great importance to determine as nearly as
possible the limits of alkali endurance of the date palm, as it is the
most profitable crop than can be grown in very alkaline lands, and on
large areas in the hotter arid regions of the Southwest it is the only
paying crop that can succeed. A careful study of the growth and
fruitfulness of the date palm at various points in the Sahara desert
shows that although this plant can grow in soils containing from 3 to
116 THE DATE PALM.
4 per cent of their weight of alkali, it does not produce fruit unless its
roots reach a stratum of soil where the alkali content is below 1 per
cent, and does not yield regular and abundant crops unless there are
layers in the soil with less than 0.6 per cent of alkali. The surface
soil may, however, be very much more salty, and may even be covered
with a thick crust of alkali. It is probable that amounts of alkali
below 0.5 per cent of the weight of the soil exert no appreciable
injurious influence on the date palm. For example, in a flourishing date
plantation at Ourlana, in the Algerian Sahara, at the spot shown in Plate
XVII, figure 1 (Ourlana, station No. 2), the surface foot of soil contained
no less than 1.52 per cent of alkali and was covered with a crust, while
the subsoil at 2 to 3 feet showed only 0.51 per cent of alkali. The
water used to irrigate this soil contained 0.64 per cent of soluble salts,
of which 0.40 per cent consisted of injurious alkali. Both in the soil
and in the irrigation water the chlorids, very harmful to most plants,
predominated; they constituted 80 per cent of the alkali in the sur-
face soil, 40 per cent in the subsoil, and 52 per cent of the dissolved
salts in the water. These amounts of alkali of so harmful a character,
though sufficient to prevent the culture of any ordinary crop, seemed
to be entirely without influence on the growth or yield of the date
palm.
If the soil at all depths contains somewhat more than 0.6 per cent of
alkali the growth is slower and the yield less than in better land, and
where the alkali content is everywhere over 1 per cent date palms
do not bear fruit regularly and their growth is very slow. On trees
growing in the presence of very large amounts of alkali the leafstalks
are usually of a pronounced yellowish color instead of the normal gray
green; on such soils in the Sahara the only other vegetation that can
exist is a scanty growth of samphires and saltbushes. (See PL XV, figs.
1 and 2.)
It must be borne in mind that the percentages given above are for
the stratum of soil containing the least amount of alkali and that the
surface layers may contain very much more, since the date palm has
A diseased condition of the date palms called at Fougala, Algeria, "meznoon" (zas
in azure), meaning " crazy," occurs rather often among the trees growing on the
, worst alkali spots and maybe caused in some way by the presence of excessive
amounts of saline matters in the soil. The leaves of such' palms do not unfold prop-
erly, but remain dwarfed and distorted, as is shown in Plate XV, figure 2. (This
figure shows in the foreground the samphires and saltbushes characteristic of the
most alkaline soils. ) These meznoon palms are said to be cured in some cases by
cutting off all the young leaves and hollowing out the bud, as is done in making
' ' lagmi ' ' or palm wine. When the new leaves push out some months later they
are sometimes normal. The Arabs sometimes attempt to cure such trees by tying the
youngest leaves into a compact bundle. A somewhat similar disease is described by
Masselot (Bui. Direc. Agricult. et Comm., Tunis, vol. 6 (1901), No. 19, p. 134) as
occurring in the Tunisian Sahara, where it is called "boussaafa." It attacks princi-
pally young palms and by preference the Deglet Noor variety.
ALKALI RESISTANCE OF DATE PALM. 117
the very important peculiarity of being able to withstand large amounts
of alkali at the surface of the ground without the crown being injured
thereby. Probably this is to be explained by the fact that, like other
palms, the date tree has no bark and no delicate cambium layer just
beneath; a date palm may be cut all about without dying when an ordi-
nary fruit tree so girdled would perish.
In consequence of the ability of the date palm to endure great
accumulations of alkali at the surface of the ground, the "rise of
alkali" from the subsoil, so dreaded by growers of other crops, is often
not at all dangerous to this plant and may even be advantageous in
some conditions, provided thereby the alkali content of the subsoil in
which the feeding roots extend is reduced. It is conceivable that in the
Salton Basin, California, where, in consequence of the very slight rain-
fall, the alkali is often very uniformly distributed throughout the soil
to great depths, it may prove desirable to draw the alkali to the sur-
face rather than to try to wash it down beyond the reach of the roots
at the risk of raising the level of the ground water and suffocating
the roots. Once accumulated at the surface, the alkali could be largely
removed, as suggested by Professor Hilgard, by scraping together
the surface crust and carrying it off the field. The difficulty is that if
by judicious irrigation the alkali should be brought to the surface
from the subsoil at a depth of, say, 4 to 6 feet, there is always danger
that a subsequent irrigation, especially if followed by an exceptionally
heavy shower, would bring up alkali from still deeper layers of the
subsoil and counteract the beneficial influence of the previous manipula-
tion. The theoretical advantage of bringing about a rise of alkali is
shown by the following comparison of a Saharan soil with one from
the Salton Basin. In the Salton Basin, at boring 133, about 5 miles
north of Imperial (Means and Holmes, Circular 9, Bureau of Soils), the
alkali is, as usual in this region, rather evenly distributed throughout
the soil. In the Sahara, at Fougala, Algeria (station No. 2), the
alkali was largely accumulated at the surface, doubtless in part because
of three years' irrigation, but also because the rainfall in this portion
of the Sahara Desert is much greater than in the Salton Basin. The
following table shows the distribution of the alkali at these two points:
TABLE 45. Distribution of alkali at different depths in the Sahara and in the Salton Basin.
[Alkali expressed in percentage of weight of soil.]
Depth.
Sahara
(Fougala,
station No.
2).
Salton Ba-
sin (boring
No. 133, 5
miles north
of Im-
perial).
Surface soil, 1 to 12 inches
1 98
1 02
Subsoil, 12 to 24 inches .
51
90
Subsoil, 24 to 36 inches (estimated for Fougala)
~ ( 44)
66
Subsoil, 36 to 48 inches . . .
38
61
Average, 1 to 4 feet .
83
80
118 THE DATE PALM.
Although the total alkali content of the soil to a depth of feet is
slightly greater at the Fougala station than at boring 133, the roots
of the date palm would reach a layer of subsoil containing only 0.38
per cent of alkali at Fougala, whereas in the Salton Basin station the
lowest amount of alkali is 0.61 per cent, or over one-half more than at
Fougala. Were the alkali at boring 133 to concentrate at the surface
in the same proportion as at Fougala, the lower subsoil would contain
something like 0.37 per cent of alkali. However, the soil at 5 and 6
feet in depth at boring 133 contains 0.58 per cent, which alkali con-
tent probably continues downward for many feet, so that in order to
bring about a diminution of the alkali content at any given depth it
is essential that the soil lying deeper is not wetted. Whether such an
operation can be carried out in practice is doubtful.
The view outlined above, that the accumulation of alkali at the sur-
face may be beneficial to the date palm in some soils but that such
accumulation may be dangerous to the plant if dislocated by unusually
heavy rains, is confirmed by the following remarkable observation of
Vogel, made at Moorzook in Fezzan, in the interior of the Sahara
Desert:
A heavy rain is considered a great disaster, as it destroys the houses that are built
out of mud, and also kills the date palms by dissolving the great quantities of salt
which are contained in the soil. For example, about twelve years ago [in 1843?]
about 12,000 date palms were destroyed in the vicinity of Moorzook by a rain which
lasted seven days. rt
Moorzook is said to have no regular rainy season, though light
showers occur in autumn. There is an abundant supply of under-
ground water near the surface. Rohlfs says: "The palms do not
require artificial irrigation [in Fezzan], since the roots seem to reach
water everywhere." 6 Date palms are said not to be watered except
during the first six months after they are set out; Under these con-
ditions a great accumulation of alkali near the surface is to be expected,
and the disastrous result of a heavy rain in washing the alkali down to
the level of the roots is not surprising.
This indifference of the date palm to surface accumulations of alkali
constitutes one of its greatest advantages over other crop plants for
culture on alkaline soils.
RESISTANCE OP THE DATE PALM TO CHLORIDS.
The date palm seems to be resistant to all kinds of alkali, with the
possible exception of the soluble carbonates, or black alkali. Common
salt and the other chlorids, including the very poisonous magnesium
chlorid so injurious to most cultivated plants, are resisted very well
Vogel, Ed. In Petermann's Geogr. Mitth., 1855, p. 250.
& Reise durch Nord-Afrika von Tripoli nach Kuka. In Petermann's Geogr.
Mitth., Ergiinzungsheft No. 25.
ALKALI RESISTANCE OF DATE PALM. 119
by the date palm which was seen growing at Chegga, Algeria, in a soil
containing about 0.8 per cent of chlorids, while amounts of chlorids
as great as 0.2 per cent were apparently entirely without effect on the
date palm at Ourlana, Algeria.
RESISTANCE OF THE DATE PALM TO SULPHATES.
Sulphates, such as Glauber's salt (sodium sulphate), are still less
injurious than chlorids to the date palm, which, when well estab-
lished, is able to withstand enormous amounts of these salts probably
from 2 to 5 per cent. Roots of the California fan palm, which is
probably no more resistant to alkali than the date palm, were found
at Palm Springs in the Salton Basin, California (see p. 112), rami-
fying abundantly in a layer of subsoil 6 feet below the surface, where
there was 4.52 per cent of Glauber's salt and 0.26 per cent of magne-
sium sulphate present. Allowing 0.02 per cent as the amount of
g}^psum (calcium sulphate) that would go into solution in the soil
moisture, the total sulphates would amount here to 4.80 per cent of
the weight of the soil. Even greater amounts of sulphates were
observed in the surface soil at Chegga, Algeria, where they amounted
to 5.11 per cent of the weight of the soil, 4.89 per cent being Glauber's
salt; the subsoil here contained 1.82 per cent of sulphates, which rep-
resents more nearly what the roots had to withstand, although in
addition there was 0.88 per cent of chlorids. It is clear that, like
other plants, the date palm can resist sulphates much better than
chlorids.
RESISTANCE OF THE DATE PALM TO CARBONATES (BLACK ALKALl).
Whether the date palm can resist the dreaded " black alkali," a the
soluble carbonates, is not settled as yet, for none of the soils from the
Sahara contained any appreciable amount of these very poisonous
salts. At Tempe, Ariz., a soil obtained from the vicinity of the
Cooperative Date Garden, where date palms grow luxuriantly, con-
tained some 0.06 per cent of sodium carbonate in the surface foot.
Well-drained soils containing an excess of gypsum, such as was
observed in all the Saharan samples, can not contain any considerable
amounts of soluble carbonates, for if any such salts existed they
would immediately react with the gypsum present, and as a result
inert calcium carbonate (limestone) and comparatively harmless sodium
and potassium sulphates would be formed.
Professor Hilgard has demonstrated the possibility of reclaiming
black alkali lands by the application of sufficient amounts of gypsum
a The name " black alkali " is applied because the soluble carbonates change the
usually gray desert soils to black, as a result of their action in dissolving the humus.
In contrast to black alkali, other soils are called "white alkali," from the color of
the surface crusts that form in very alkaline spots.
120 THE DATE PALM.
to decompose the soluble carbonates present in the upper layers of the
soil. It is not impossible that the obvious injury which results to the
date palm from imperfect drainage may be caused by soluble carbon-
ates, which can form under such conditions, even in the presence of
gypsum. a It is a matter of much importance to determine the limits
of resistance of the date palm to black alkali, as to which it is now
impossible to speak with any certainty. 6 Even if the date palm proves
to be sensitive to the soluble carbonates it will nevertheless still be
possible to engage in date culture on black alkali lands by treating
them with gypsum and providing for good drainage.
As yet no data are available for a study of the comparative alkali
resistance of the different varieties of the date palm, but doubtless a
careful investigation would show that there exists a considerable vari-
ation in this important character. Marked differences are known to
exist among the diverse sorts of date palms in their ability to endure
cold (see footnote, p. 61), and, as shown in the chapter on heat require-
ments, there are enormous differences in the amounts of heat required
to ripen early and late varieties; it is reasonable to expect similar lack
of uniformity in their ability to withstand alkali. The great impor-
tance of date culture, constituting as it does the only profitable industry
that can be followed on very alkaline lands, would warrant a careful
search in the date plantations in the most alkaline regions of the Old
World deserts, in the hope of securing varieties still more resistant to
alkali than those we now possess.
The high degree of alkali resistance of the date palm permits
brackish water to be used in irrigating. Commercial date plantations
of large extent exist at Ourlana and at Chegga in the Algerian Sahara,
Color is given to this supposition by the observation of Masselot (Bui. Direc.
Agric. et Comm., Tunis, vol. 6 (1901), No. 19, p. 135) that a disease common among
young palms, known as "Merd el Ghram," in the Tunisian Sahara, caused by exces-
sive irrigation in badly drained soils, is accompanied by a blackening of the soil about
the plant. The palms suffering from this disease cease to grow, sicken, and turn yel-
low; they may be cured by drainage and by replacing at the same time the black-
ened soil about the foot of the tree with fresh earth. These symptoms seem to
indicate the formation of black alkali, and that it has a very injurious action on the
date palm.
& It can not be assumed that because the date palm is enormously resistant to
white alkali it must necessarily be able to support large amounts of black alkali, for
the soluble carbonates have a decidedly alkaline reaction, whereas white alkali, in
spite of its misleading name, may be nearly neutral in reaction. It is well known,
especially from the interesting experiments of Prof. H. J. Wheeler, of the Rhode
Island Experiment Station, that plants differ enormously in their requirements as to
soil reaction. Lupines, for instance, are injured by soils having an alkaline reaction,
whereas clover, soy beans, and most ordinary crop plants of humid regions are greatly
harmed by soils having an acid reaction. It is possible that the date palm is injured
by soils having a decidedly alkaline reaction, even if the amount of salts in solution
in the soil water be small.
ALKALI RESISTANCE OF DATE PALM. 121
which are irrigated with artesian water containing 0.64 per cent of
dissolved salts, and it is said that still more alkaline well water con-
taining 1 per cent of salts is used to irrigate date palms in some of the
other oases. Even the brine which seeps through the alkali soils and
runs off in the drains is used to water palms growing at lower levels,
and in some plantations no other water is available for irrigation (see
p. 98). The alkaline water from Lake Elsinore, which proved so
very disastrous to the orange orchards about Riverside, Cal., con-
tained only from 84 to 116 grains per gallon, whereas the water used
exclusively on the date plantations at Chegga, Algeria, contained
374 grains, and substracting gypsum, 250 grains per gallon of harmful
alkali. Water, such as that supplied from Lake Elsinore at its worst,
would be adapted perfectly to irrigate date palms. Even the intensely
brackish ground water under the Sal ton Basin, which lies some 50 feet
below the surface at Calexico and only about 30 feet below at Imperial,
though it contains some 0.4 to 0.6 per cent of dissolved salts, and
though it would prove fatal to most crop plants if brought up near
the surface by injudicious irrigation, would not necessarily injure the
date palm. Many plantations in the Sahara are irrigated with water
more alkaline than this. The chief danger to the date palm to be
apprehended from a rise of ground water is the suffocation of the
roots because of imperfect aeration of the water-logged subsoil.
The immense superiority of the date palm over all ordinary crop
plants for culture in alkaline lands becomes evident when it is remem-
bered that all ordinary useful plants, such as wheat, corn, and alfalfa,
peach, orange, and prune trees, etc., are killed by as much as 0.5 or 0.6
per cent of alkali in the soil, a which amount is entirely without
influence on the date palm. The more resistant crop plants, such as
barley, sorghum, sugar beets, grapevines, olive trees, and possibly
pomegranate, jujube, and pistache trees, are able to withstand from
0.6 to 1 per cent of alkali; but these plants are easily injured by an
accumulation of the alkali at the surface, which is perfectly harmless
to the date palm. About the only crop plant which can withstand
considerably over 1 per cent of alkali is the Australian saltbush
(Atriplex semibaccata), and Qven this forage plant can not endure
nearly as much alkali as the date palm probably not half as much.
As noted on page 115, asparagus is able to endure much alkali, though
the limits of its resistance have not yet been determined. The date
palm is, then, the most resistant to alkali of all plants now known cap-
able of commercial culture in arid regions.
See Means and Holmes, Circular No. 9, Bureau of Soils, U. S. Department of
Agriculture, 1902, and other publications of that Bureau.
122 THE DATE PALM.
REGIONS IN THE UNITED STATES WHERE DATE CULTURE CA:
SUCCEED.
CALIFORNIA.
Salton Basin or Colorado Desert (see Pis. Ill, IV, XVIII, fig. 1 an
fig. 10, p. 102). It is clear, from what has preceded in this bulletii
that the Salton Basin or Colorado Desert is not only the most promi
ing region in the United States, or in North America, for the cultui
of the best sort of dates, but that it is actually better adapted for th
profitable culture than those parts of the Sahara Desert where tl
best export dates are produced. This favored region, though sma
in comparison with the vast arid areas of the Southwest, is neverth
less larger than any one Saharan oasis, probably equaling in extei
all the oases in the western Sahara from Tripoli to Morocco, and
capable of producing all the dates consumed in America. Only the va
date plantations along the Valley of the Shat-el-Arab, formed by tl
junction of the Tigris and Euphrates rivers, near the head of the Pe
sian Gulf, which furnish most of the great quantities of dates consume
in the United States, are comparable in extent with the irrigable po
tion of the Salton Basin.
The study of the life histor}^ of the date palm has shown that in tl
Salton Basin the long, hot summers, the very dry atmosphere, and tl
almost complete absence of rain during the flowering and ripenir
seasons of the date palm render the climate particularly adapted
the culture of the choice late-ripening sorts, such as the famous Degl
Noor. At the same time the presence of an abundant supply of wati
of excellent quality and the extreme fertility of the soil render tl
conditions unusually propitious for the establishment of this profitab
fruit culture. The presence of considerable amounts of alkali in tl
soil has been shown to be no obstacle to the growth of this plant, whic
is harmed only by exceptionally large quantities of alkali. Inde<
the presence of alkali, by rendering much of the land ill fitted <
entirely unsuitable for other culture, constitutes one of the most coge:
reasons for the speedy introduction of this resistant plant in order
enable all the lands now under irrigation to be put to profitable use.
Death Valley (see map, PL IV). The Death Valley, a depression
some places 320 feet below sea level, situated in east central Calif orni
near the boundary of Nevada, is in many ways very like the Salt(
Basin, and may be considered as a more northern extension of tl
same general conditions. Being some 4 degrees (300 miles) farth
north than the Salton Basin, the winters are probably much colde
and possibly only hardy varieties of date palms will succeed, though
is probable that most sorts can be grown in certain protected situ
tions if well covered in winter when young. The summer heat
Since the above was written, an experimental date garden has been establish
in the Salton Basin at Mecca. (See footnote, p. 110.)
Bui 53, Bureau of Plant Industry. U. S. Dept. of Agriculture
PLATE IV.
OREGON
EXPLANATION
|Ji [] INTERIOR VALLEY REGION
PLATEAU REGION
COLO.RIVERVALLEYREGION
DEATH VALLEVREGIO.N
SALTON BASIN REGION
RELIEF MAP OF CALIFORNIA, SHOWING THE PRINCIPAL REGIONS
WHERE DATES CAN BE GROWN.
DATE CULTURE IN CALIFORNIA. 123
intense, nearly equaling that of the hottest parts of the Salton Basin;
and even very late sorts, such as the Deglet Noor, could mature here
perfectly. There is almost no rain, and in consequence no danger of
the fruit being spoiled by wet weather during the ripening season in
autumn. Unfortunately, there is almost no water available for irriga-
tion in the Death Valley, and no large streams occur in the surround-
ing country which could be diverted into this desert. It is not known
whether artesian water underlies this region, but if flowing wells could
be dug it would be desirable to make a thorough test of the Deglet
Noor and other first-class late sorts of dates. The date palm is par-
ticularly well adapted for culture in such regions remote from rail-
ways and from markets, as the crop can be transported to great
distances without injury and, being a high-priced dried fruit, repre-
sents about the maximum of value, in proportion to the weight and
bulk, among agricultural products.
Colorado River Valley (see map, PL IV, and fig. 10, p. 102). This
valley, lying partly in California and partly in Arizona, and espe-
cially the flood plain, which is irrigated and fertilized naturally
by the annual overflow of the river offers considerable promise
of being able to produce early drying dates at a cost low enough to
enable them to be sold in competition with the so-called Persian dates,
which are shipped to our markets in enormous quantities from the
region about Bassorah, near the head of the Persian Gulf, and from
Maskat, in Arabia. A detailed account of this promising region is
given below (p. 129), in treating of the regions suitable for date culture
in Arizona.
Plateau region (see map, PI. IV). This tableland, comprising the
Mohave Desert, separating northern from southern California, would
be fairly well adapted for date culture were it not for the fact that
the winters are almost everywhere too cold. However, in canyons
facing southward, where the cold air can drain off at night to lower
levels, the hardier varieties may pass the winters uninjured. From
the weather records kept at Keeler and Barstow it would seem proba-
ble that the date palm might succeed in the vicinity of these towns.
If any attempt is made to grow dates in this part of California atten-
tion should be paid to the results of the experiments in date culture
made by the California Experiment Station at Tulare, where it was
found that irrigation in late summer is very disastrous to the date
palm, because it forces a late growth, which is injured during the fol-
lowing winter. However, all through the plateau region the summer
heat is insufficient to ripen any but early sorts, and it is very unlikely
that date culture will prove a profitable industry in this part of Cali-
fornia.
Interior Valley region (see map, PI. IV). The largest continuous
area in California, and perhaps the largest in the world where dates
can be grown, is the interior valley region, comprising the valleys of
124 THE DATE PALM.
the Sacramento and San Joaquin rivers. The climate is here very
different from that of the other regions mentioned above, especially in
the much heavier rainfall, which in many places is sufficient to permit
the date palm to grow without irrigation. As a result of this more
humid climate there is more danger of damage to the flowers in spring,
and especially more risk of losing the ripening fruit in autumn, in
consequence of a spell of wet weather. The summer season is nearly
or quite rainless; otherwise date culture would be impossible.
As a result of investigations on the life history of the date palm, it
is evident that only the very early sorts can mature their fruit in this
region, owing to the insufficient summer heat. These earliest vari-
eties, though often a very palatable fruit, suitable for home consump-
tion, are as a rule unfit for drying and for export. Experiments are
now under way in cooperation with the California Experiment Station
which will decide in a few years whether any of the early Saharan,
Egyptian, and Arabian sorts suitable for drying can mature in this
region.
All parts of the San Joaquin and Sacramento River valleys offer
about equal advantages for date culture, except in the region where the
two rivers unite. This section lies directly east and northeast of San
Pablo and Suisun bays, and the cold winds which blow in from the
Pacific over San Francisco Bay find their way eastward through this
break in the coast range, and thus lower the summer temperature; it is
unlikely that any dates can be ripened in this area, which extends
from Stockton to Sacramento and across the valley to the foothills.
The winters are mild enough in most parts of the interior valley
region to permit date palms to grow without injury, provided they are
protected when young. In some of the colder localities only hardy
sorts will succeed, and at Tulare it has been found by the California
Experiment Station that several of the Egyptian sorts imported in
1889 by the Department of Agriculture are severely injured by
freezes in winter, especially if by late irrigation the palms had been
kept growing in late summer and autumn (see p. 49). In such cold
localities no irrigation should be given after midsummer.
It is interesting to note that the Wolf skill date (fig. 3, p. 31, and
Yearbook, 1900, PL LXII, fig. 2), which grows at Winters (latitude
38 32' north), about in the latitude of Washington, Lisbon, Athens,
and Peking, is much farther north than any bearing date palm in the
Old World, with the exception of one tree at Nice, France (latitude
43 45' north), which is probably not a true date palm but a hybrid
between the date palm and the Canary Island palm. There are other
date palms still farther north in the Sacramento valley which ripen
edible dates, as for instance at Colusa and Willows, at both of which
points date palms are growing which occasionally ripen a few fruits. a
The Bee, Annual for 1902, p. 3: reported by Mr. J. M. Silvey, of Willows, and
W. S. Green, of Colusa.
DATE CULTURE IN CALIFORNIA. 125
Indeed, the summer climate at Orland, Corning, Tehama, and Vina,
in latitude 40, seems to be as good as at Winters, and to be only
slightly less suitable at Red Bluff or even at Redding, latitude 40 30',
almost under Mount Shasta. Nowhere else in the world are there any
such extensive regions north of latitude 35 where dates can be grown
successfully.
Even if dates suitable for drying can not be produced here, it will
certainly be possible for settlers all through this region to produce
fresh dates for their own tables, and it is quite probable that these
fresh dates can be shipped to the principal Pacific coast cities without
spoiling.
Coast region of southern California. Although the winters are
never severe enough to injure the date palm and almost no rain falls
during summer and early autumn, it is nevertheless very improbable
that good dates can be grown in this part of California, for the simple
reason that the winds which blow off the ocean are cold and humid and
prevent the summer heat from being sufficient to ripen dates for 25
miles or more from the coast. It has been found that the date palm
does occasionally ripen fruit at San Diego (see PI. XX, fig. 1), but
the plant is forced entirely out of its normal habits by the very low
temperatures which prevail here in spring and summer, and instead of
flowering in April, as it does in the Sahara, often does not open its
flower clusters until August, in which event the half -grown dates hang
on the trees in a green condition all through the winter and ripen only
during the following summer. The date palm referred to above,
which ripens its fruit at Nice, may be found adapted to the climate of
this coast region, but unfortunately this tree has not yet produced any
vigorous offshoots and only seedlings are available for testing in Cali-
fornia. The best chance of securing dates capable of ripening in this
region is by cross fertilizing early varieties with the pollen of the
Canary Island palm (Phoenix canariensis), which, being adapted to the
relatively cool and humid, though nearly rainless, summer climate of
these islands, is able to mature its thin-pulped and flavorless fruit all
along the California coast, even as far north as San Francisco. It is
probable that the palm at Nice is such a hybrid, and that it will be easy
for plant breeders, by selecting among numerous hybrids, to find a sort
much better than this chance seedling.
NEVADA.
It is probable that the date palm may be fruited successfully in some
of the protected valleys in southern Nevada; early sorts are, indeed,
almost certain to succeed in the valley of the Colorado River wherever
there is 'any land that can be planted. The actual flood plain, being
both higher in altitude and farther north than in California and Arizona,
126 THE DATE PALM.
may prove to be too cold in winter for any but hardy sorts, and, as
noted below (p. 132), the annual inundation with cold water will pre-
vent the ripening of any but the earliest sorts. At higher altitude in
southern Nevada the summers are hotter, and even midseason or late
sorts can be grown if they can withstand the winter cold. For exam-
ple, at St. Thomas, in the valley of the Virgin River, at an altitude of
1,600 feet, the summers are hotter than at Phoenix, in the Salt River
Valley, Arizona, but the winters are colder, the thermometer falling
as low as 11 F. in January, 1899 a temperature which is likely to
kill young palms and injure old ones. It is not impossible that there
may be warm situations in the Pahrump Valley and in Ash Meadows,
in southwestern Nevada, though in the absence of meteorological
records it is impossible to speak with certainty, and it is probable that
the winters are almost eveiy where too cold in these valleys to permit
dates to be grown. Hardy late sorts of dates would be very desira-
ble for culture in southern Nevada, and it is probable that such could
be found in the oases of Persia, where the winter cold is sometimes so
severe as to injure or even kill old date palms, although the summer
heat is intense. Inasmuch as such sorts would be of great value for
culture not only here but also in southwestern Texas and in some parts
of California, it would seem advisable tc make a thorough search in the
Persian oases as soon as possible and to secure the best varieties for
trial in America.
ARIZONA.
As has been explained above (p. 61), in treating of the drainage of
cold air and the inversion of temperature in relation to date culture,
the earlier varieties will probably succeed in some parts of Arizona
lying as high as 5,000 feet above sea level, and medium or late sorts
in most parts below an altitude of 2,000 feet, except where there is a
marked drainage of cold air from some higher level. This area lying
below 2,000 feet in altitude would include the whole of southwestern
Arizona, with an arm running up the Gila River, and also extending
up the Salt and Verde rivers, and another extending along the Colo-
rado river northward, passing up the tributary called Bill Williams
River, and reaching as far north in the Grand Canyon as the Hualapai
Indian Reservation. This portion of Arizona lying below the 2,000-
foot contour line forms on the map the shape of a capital L with a
very thick horizontal limb. It must not be supposed, however, that
any large part of the 20,000 or more square miles included in the area
above limited will ever be planted to date palms or to any other fruit
trees, since most of this area is without adequate water to carry on
agriculture. The irrigable areas along the Gila River and its tribu-
taries, especially the Salt River Valley, the Upper Gila Valley from
Florence westward to the Estrella Mountains, and finally the valley of
the lower Gila, especially about Gila Bend, are the localities best
DATE CULTURE IN ARIZONA. 127
adapted to the culture of the date palm. The whole of the valley of
the Colorado, so far as it is irrigable, and especially the flood plain
naturally irrigated by seepage from the river and by the annual over-
flow, is also adapted to the culture of the date palm, but probably
only the earlier varieties will succeed. Of the regions just mentioned,
only two are now furnished with a sufficient supply of water to ren-
der date culture possible on any large scale. These are the Salt River
Valley from Mesa westward to Peoria, and the flood plain of the Colo-
rado River. Wherever small amounts of water are available in the
other valle3^s they could be utilized for irrigating date palms, which
would undoubtedly succeed, and it is probable that in the future, with
increased facilities for irrigation, the upper and lower valleys of the
Gila will prove especially suited to this culture.
There is a region in south central Arizona, lying to the south of the
Casa Grande ruins, where there are said to be thousands of acres cov-
ered with a heavy growth of mesquite trees (Prosopus velutinusf] and
where water is found at a depth of from 20 to 30 feet below the sur-
face. It is not impossible that if date palms were irrigated in this
region when young, they might be able to grow without irrigation
after the roots reached moisture. At any rate, both here and else-
where, where a heavy growth of mesquite occurs and where there are
indications of underground water near the surface, it would be desir-
able to make trial plantations of the date palm.
Salt Riv&r Valley. This fertile region, which is one of the largest
of the irrigated valleys in the Southwest, is situated in central Ari-
zona (latitude 33 25'). Its principal towns are Phoenix, Tempe, and
Mesa. As has already been mentioned, the date palms planted by the
earlier settlers have been striking^ successful (see Yearbook, 1900,
PI. LVII); in fact, it is no exaggeration to say that there are more
bearing date palms producing fruit of good quality in the Salt River
Valley than in all the rest of the United States. The Cooperative
Date Garden at Tempe (see Pis. XXI and XXII) on June 15, 1902, had
on hand (including a few palms at the experiment station farm at Phoe-
nix) 556 trees, belonging to 81 varieties. Besides these 81 imported
varieties, there are a number of seedling sorts of merit which have
originated in the Salt River Valley, so that in all there are probably
nearly 100 distinct varieties of date palms now on trial in this valley. a
Prof. James W. Tourney, while connected with the University of Ari-
zona, investigated the whole subject of the culture of the date palm in
the United States and brought out very clearly in a bulletin 6 published
in June, 1898, the fact that in these regions only had the plants imported
Forbes, R. H. Thirteenth Annual Report, Arizona Experiment Station, 1902,
p. 244.
& Tourney, W. J. The Date Palm, University of Arizona, Arizona Agricultural
Experiment Station, Bulletin No. 29, Tucson, Ariz., June, 1898.
128 THE DATE PALM.
by the Department of Agriculture in 1889 and 1890 grown rapidly
and produced good fruit abundantly. This bulletin was the first
important study of the date palm published in America, and it did
much to attract attention to the possibility of establishing date cul-
ture as a profitable industry in the Southwest.
Although there are many regions in California, and some in Ari-
zona, where the summer temperatures are higher than they are in the
Salt River Valley, the only considerable area of land under irrigation
where the climate is more favorable to the date palm is the Salton
Basin in California. It may be stated that date culture is no longer
an experiment in the Salt River Valley. It is, however, not yet cer-
tain that the Deglet Noor variety, which brings the highest price in
the market, will come to full maturity here. It is to be hoped that it
will, and the outlook is not without promise (see p. 68). If this vari-
ety does ripen properly, there can be but little question that it will be
profitable to plant it on the best lands in the valley and to irrigate it
abundantly. The 'question as to whether the Deglet Noor can mature
its fruits in central Arizona will be settled within a very few years by
the experiments now in progress at Tempe, in this valley (see PL XXII).
In case the Deglet Noor does not succeed in this valley, the effort
should be made to produce a date intermediate in quality between the
Deglet Noor and the ordinary dates sold in bulk in this country. Such
a good second-class date would compete with the selected Bassorah and
Maskat dates for household uses and take the place of Deglet Noor
dates to some extent for use as a dessert fruit. Owing to the nearness
to markets, the Salt River Valley dates could be sold while still fresh
and need not be deformed by the close packing needful to preserve
the oriental dates from drying out or from spoiling while en route to
America.
The collection of varieties at the Cooperative Date Garden at Tempe
is by far the most complete in the world, since it comprises the best
known varieties from the Algerian Sahara, from Egypt, and from the
regions about Bassorah and Maskat, where most of the dates imported
into America are produced, as well as a large collection of varieties
from the Pangh Grhur region in Baluchistan. Together with the seed-
lings that have originated in the valley and the sorts growing at the
experiment station farm at Phoenix, there are something over 90
named varieties now on trial in the Salt River Valley. It is very
probable that some of these will prove to be adapted for profitable
culture in this valley, even if the Deglet Noor can not mature.
There are several seedling dates that have originated in the Salt
River Valley in Arizona which promise to be valuable. One of the
best of these is the Lount No. 6. It is small, being rather smaller than
the Wolf skill date, but of very good texture, of clear amber color when
dried, and of fairly good flavor. The Kales date and the Bennet date
(fig. 4, p. 32) are seedlings of considerable merit, also growing near
DATE CULTURE IN ARIZONA. 129
Phoenix, Ariz. In addition, there are several other seedling varieties
of considerable value which have already fruited in central Arizona,
some of which may prove adapted to culture on a large scale.
Two of the varieties introduced from Egypt by the Department of
Agriculture in 1890 have been fruiting for some time at Phoenix, Ariz.
In 1900 one of the sorts, the Amreeyah, bore over 300 pounds (see
Yearbook, 1900, PL LXII, fig. 1), while another, the Seewah, bore
over 200 pounds. These dates were packed in half-pound boxes, and
Prof. A. J. McClatchie writes that they sold readily for 20 cents a box
wholesale and 25 cents retail, and there was a demand in the local mar-
ket for ten times the quantity that could be furnished. The Seewah
in particular is a very promising date for culture in the Salt River
Valley, in Professor McClatchie's opinion, as it is fairly early and of
excellent quality.
Although a good second-class date could doubtless be grown with
profit on the best fruit land, it is probable that this culture will be
undertaken first on lands too alkaline to be safe for other crops. Some
of the low-lying alkali lands, especially near the date garden at Tempe,
have water rising to within a few feet of the surface, which seeps down
from the surrounding irrigated fields lying at higher levels. Date
palms, when once established, will grow in such situations without
any irrigation at all, though they will grow better and yield more
fruit if occasionally irrigated from the surface with pure water from
the canals.
Colorado River Valley (see fig. 10, p. 102). The valley of the Colo-
rado River, lying partly in Arizona and partly in California, comprises
two adjoining though different situations where the culture of date
palms is possible, viz, the flood-plain of the river and the mesa lands
lying above the high-water mark not subject to inundation.
The immediate flood-plain is flat and only a few feet (10 to 15) above
the low-water mark. It is in some places so narrow as to be only a
strip along the bank, while below Yuma and again farther north in the
Colorado River Indian Reservation, it is often several miles in width
and is covered with a luxuriant growth of willows. The flood-plain is
subject to annual inundation from the Colorado River, which overflows
its banks every year, like the Nile in Egypt, when the summer heat
melts the snows on the high mountains at the headwaters of the river
in Colorado and Utah. The retiring flood waters leave a thick deposit
of mud, which renders the soil exceedingly fertile. a
In 1899 the writer saw a dense growth of 5 to 6 year old willow trees being cut
for cord wood. The trees were 25 to 35 feet in height and from 6 to 10 inches in
diameter near the ground. Any possible doubts as to the accuracy of the determina-
tion of the age of these trees, which was made by counting the annual rings of growth,
were dispelled by the evidence of a woodman, who asserted that some five years
before all trees of any considerable size had been cut from this tract of land.
13529 No. 5304 9
130 THE DATE PALM.
The position of the larger bodies of easily irrigable land lying along
the Colorado River is shown in fig. 10, p. 102. The cross-hatched areas
in this figure along the river indicate low-lying lands, and are more
extensive than the flood-plain proper, although in very high flood most
of the areas marked on the map would be overflowed. All these lands
are easily irrigable without expensive diversion works, which would
be necessary were the water to be conducted to the mesas overlooking
the Colorado. The land comprised in these areas amounts to some 800
square miles, 05 distributed as follows:
Square miles.
Cottonwood Valley in Nevada and Arizona 14
Mohave Valley in Nevada, California, and Arizona 160
The small valleys near the junction of the Bill Williams River 56
The great Colorado Valley in California and Arizona 382
The valley in California and Arizona just above the junction of the Gila River
at Yuma 80
The valley on the right bank of the river below Yuma in Arizona 108
There is a large area of similar land in Mexico along the Colorado
River, as may be seen from the sketch map, fig. 10, p. 1 02.
Recent detailed surveys made by the Hydrographic Office of the
Geological Survey b show that there are between 400,000 and 500,000
acres of irrigable land in the valley of the Colorado River between
Fort Mohave and Yuma, and there are in addition large areas of land
in Arizona below Yuma already irrigated, while still more can be put
under water at slight expense. The flood-plain proper, naturally irri-
gated by the annual overflow of the river, does not comprise so exten-
sive an area, but nevertheless embraces several hundred square miles
of the very richest of these exuberantly fertile alluvial soils.
Of the 100 square miles (63,469 acres) surveyed in 1902 in the Colo-
rado River Valley south of Yuma, Ariz., Holmes says: "About To per
cent of the lands of the valley are overflowed and a layer of sediment
added to the soil each year. The deposition has been much greater
near the present stream bed than farther back, so that the lands
immediately bordering the stream are higher and covered by only a
few inches of water during the flood season, while those farther back
may in places stand under 7 or 8 feet of water."
The land near the river is usually nearly free from alkali, which
occurs ehielly "just above the high- water line of present overflow,
where evaporation from the surface has taken place without any sur-
face flooding, showing plainly that the alkali is the result of the
An estimate of 700 square miles is made by Whipple, Pac. Ry. Rept., vol. 3,
Pt. I, pp. 40-41, to include the lands from Fort Mohave to Yuma.
&Lippencott, J. B., and Davis, Arthur P. Colorado River Division in Arid Land
Reclamation Service, First Annual Report, 1903, pp. 106-125.
c Holmes, J. Garnett. Soil Survey of the Yuma Area, Arizona. In Field Oper-
ations of the Bureau of Soils, Fourth Report, 1902, p. 781.
DATE CULTURE IN ARIZONA. 131
evaporation of the river water. Other alkali areas are found along
the foot of the bluff, being caused by a small amount of seepage from
the high lands above. " a
In regard to the control of the overflow water, which is the problem
of first importance in all ordinary agriculture, Holmes says: "Until
this water is effectually in hand no farming worthy of the name can be
done. To control the overflow it will be necessary to construct a dike
or levee along the river, to connect with the mesa land below, of such
height and strength as to keep out the river. As has been previously
stated, the ground water of the valley rises and falls with the river,
and some places are now overflowed 6 to 8 feet. The confining of the
river would cause it to rise higher in the channel, so that the ground
water over the present overflowed part of the valley would have sev-
eral feet of head, thus bringing it near to or above the surface. This
would necessitate the installation of a drainage system, with a pump-
ing plant at the lower end of the valley to lift the water above the
levee and back into the river. This leveeing and draining would be
expensive, but since the subsoil is usually quite porous the drains
need not be close together, and the natural fertility of the soil,
together with the advantages of abundant water and almost tropical
climate, would certainly make such reclamation a paying investment." 6
If it is found, as now seems probable, that the date palm can be
grown on the lands subject to overflow without artificial irrigation and
without any such expensive system of levees and of drainage by pump-
ing, then it will doubtless be possible to grow dates here as cheaply
as in the Bassorah- region, where likewise no hand labor is necessary
to carry out irrigation when once the canals have been dug. c
The luxuriant growth and abundant fruiting of the seedling date
palms (PL XX, fig. 2) grown by Mr. Hall Hanlon in the flood*plain
some miles west of Yuma, on the California side, show that, in some
places at least, the seepage from the river, which goes on throughout
the year, and the thorough soaking which the land receives at the
time of the annual overflow, render irrigation unnecessary. The
deposit of mud left by the flood waters suffices to maintain the fertility
of the soil and renders any manuring superfluous.
Although the meteorological records kept for several decades at
Yuma, Ariz., on the banks of the Colorado River, show the summer
climate to be nearly as hot as at Phoenix, in the Salt River Valley
(though much cooler than in the Salton Basin), the dates planted by
Mr. Hanlon usually fail to mature and must be ripened artificially.
As was mentioned above, on page 50, this failure to mature the fruit
Holmes, J. Garnett, Soil Survery of the Yuma Area, Arizona, 1902, p. 786.
& Holmes, J. Garnett, 1. c., p. 791.
c Fairchild, D. G. Bulletin 54, Bureau of Plant Industry, U. S. Department of
Agriculture, p. IK.
132 THE DATE PALM.
is probably due in part at least to the lowering of the temperature
of the soil about the roots 65 and of the air about the leaves by the
overflow of cold water from the melting snows of the Rocky Moun-
tains. This annual flood occurs in the midst of the hot season, usually
early in June, and the waters remain on the land for several weeks.
Early sorts of dates, such as the Rhars and Teddala, undoubtedly will
succeed in this favored region, which has many advantages for this
culture. The land is irrigated and fertilized naturally, the dry air
favors the ripening of fruit of a good quality, the very low rainfall
in spring and autumn permits the date palm to flower and ripen its
fruit unhindered by bad weather, and the winters are so mild that no
injury by cold is to be apprehended after the young palms have once
taken root.
The date palm has a great advantage over other fruit trees for
culture in the flood plain, in that, when once established, it can resist
the erosive force of the flood waters without being injured or losing
its crop of fruit. There are thousands of acres of this land in Cali-
fornia and Arizona now lying waste which could be utilized for this
profitable culture if a variety of date palm could be found which pro-
duces early ripening fruit fit for drying, and which is adapted to the
soil and climatic conditions of this region. Indeed, the chance to
secure exuberantly fertile lands, requiring no irrigation, at low
prices, gives this flood-plain great economic advantages over other
regions for the production of an ordinary or second-class date, such as
those that are now imported into this country in enormous quantities
from the somewhat similar region about Bassorah, in the valley of the
Shat-el-Arab at the head of the Persian Gulf, and from Maskat. No
fewer than 9,000 tons of these dates were imported in 1901, so the
market is practically unlimited, provided the cost of production can
be kept down to a point permitting competition with the oriental
dates. The date producer in the Colorado River Valley would have
the great advantage over his Bassorah rivals of enormously greater
proximity, both in distance and in time, to the great markets in the
interior of the United States.
The prospect for successful culture in this region of the ordinary
dried dates, one of the staples of the fruit trade, is so good as to war-
rant making a careful search in the Old World date countries for
suitable sorts to grow here. Fortunately, the Department of Agri-
culture has already secured and has growing in the Cooperative Date
Garden at Tempe, Ariz. , many of the early-maturing sorts of dates
from the Algerian Sahara, as well as from the valley of the Nile in
Egypt and the valley of the Shat-el-Arab at Bassorah, the two latter
regions having climatic and soil conditions somewhat resembling those
a As shown on p. 49, warm irrigation water is very advantageous in date culture.
Doubtless the date palm is as sensitive to the soil temperature as to the air temperature.
DATE CULTUKE IN NEW MEXICO. 133
of the Colorado River Valley. In addition, the varieties from the
island of Djerba, off the coast of Tunis, where only early sorts can
mature, as well as the many- early kinds reported from the Tunisian
Sahara, should be secured for trial. Possibly other sorts of value
could be found among the multitudes of seedling date palms growing
in the valleys of the Indus and its tributaries in the Punjab, in India.
On the higher lands along the valley of the Colorado the conditions
are very different from those described above, for, lying above the
flood-plain, these lands are not subject to annual overflow and con-
sequently there is no lowering of the summer temperature by the cold
flood waters. The meteorological records kept at Yuma, Ariz., near
the Mexican boundary, and at Needles, Cal., near the Nevada bound-
ary, indicate that midseason and even late sorts, including possibly
the Deglet Noor, may be expected to mature fully in this region. a So
there is a good prospect for successful date culture wherever it is
possible to irrigate the land.
NEW MEXICO.
All of New Mexico is over 2,500 feet above the sea level, and nine-
tenths of its area is above 4,000 feet in altitude. In consequence the
winters are almost everywhere too cold to permit the culture of any
but hard}^ sorts of the date palm, and- the summer heat is inadequate to
ripen any but the earliest varieties. The winters are much too cold for
the date palm in the principal irrigated regions, the valleys of the Rio
Grande and the Pecos rivers, where this plant would be very useful
for planting on alkali lands. From a study of the meteorological rec-
ords, it would seem that La Paz, at 4,836 feet altitude, in south central
New Mexico, near the Sacramento Mountains, has the most promising
climate for date culture. The next best climatic region is found in
the vallej^s of the Gila and Rio Mimbres, in the southwestern corner
of the Territory. This latter region is of considerable extent, but
unfortunately the winters are usually so cold that young palms would
be injured if not protected. During the cold wave of 1899 the tem-
perature fell below 7 F. at all the stations where records are kept,
except at Gage, altitude 4,480 feet, where the record shows a minimum
temperature of only 16 F.
Very early sorts of date palms capable of withstanding much cold
are needed for trial in New Mexico. Such sorts are most likely to be
found in the oases of Persia, especially in those which from their high
altitude or northern position have a very cold winter climate. The
northern Sahara, though it contains early varieties suitable for culture
in the interior valley region in California and in the Colorado River
Prof. R. H. Forbes is strongly of the opinion that the Deglet Noor date will ripen
in the Colorado River Valley about Mellen and Fort Mohave, Ariz., where the
climate is exceptionally hot. (Letter to the author, dated Tucson, March 1, 1904.)
134 THE DATE PALM.
flood plain, where the winters are comparatively mild, is unlikely to
yield sorts suitable for New Mexico or for the plateau region of Cali-
fornia, where hardiness is indispensable, for the reason that in the
northern Sahara, even in oases lying at high altitudes, the winter cli-
mate is comparatively mild and equable.
TEXAS.
Only the extreme southwestern part of Texas, bordering the Rio
Grande from the mouth of the Pecos River to near Brownsville, is
adapted to the culture of the date palm. Throughout the eastern half
of the State and in a strip along the Gulf coast, down to the Mexican
boundary, the climate is too humid and the summers are too cool to
ripen the fruit properly, while in all the northern part of the State,
above San Antonio (latitude 30 north), the winters are too cold to
permit the date palm to grow out of doors without protection. In the
region lying south and west of San Antonio, between the humid Gulf
coast and the Rio Grande, the summers are hot enough to mature
even the medium or late varieties of dates. Fort Mclntosh, in Webb
County, at 460 feet altitude, has a summer temperature somewhat
higher for the months from May to September, inclusive, than at
Phoenix, Ariz. The rainfall averages in this region only about 10
inches, and the late summer is usually dry enough to permit dates
to ripen; irrigation would usualty be necessary. Ordinarily the
winters are not severe enough to injure the date palm if protected
when young, though this part of the State is occasionally exposed to
u northers," during which the temperature sometimes falls very low.
In February, 1899, for example, it fell to 7 F. or below all over the
region where the date could be grown, and this temperature would
doubtless injure or kill even old date palms. Such low temperatures
are, however, very exceptional, and the date should be tested in this
part of Texas wherever water can be obtained for irrigation.
Midseason and late varieties, resistant to winter cold, which are
needed here and in southern Nevada, are most likely to be found in
the depressions in the Persian plateau, where the summer heat is
intense and, at the same time, the winters are rigorous. There is
much less chance of finding hardy sorts in the Sahara, where the win-
ters are mild, especially in low altitudes, where alone there is sufficient
summer heat to ripen late varieties.
NO DANGER FROM MEXICAN COMPETITION IN DATE CULTURE.
The date palm was introduced into Mexico soon after the conquest,
probably by means of seeds brought from Spain by the missionaries.
Some of the palms in Sonora and Lower California are very old and
have reached great height. A group of such old trees is shown in the
frontispiece. They were growing at Hermosillo, only 150 miles south
MEXICAN COMPETITION IN DATE CULTURE. 135
of the United States boundary, where the climate is not very unlike
that of the hot valleys of Arizona. There are extensive date planta-
tions in Lower California, especially in the central part of the penin-
sula, and considerable quantities of dates, packed in rawhide bags, are
shipped from here to the cities of Mexico, and some even as far as
Arizona and California. According to the statistics published by the
Mexican Government, Lower California produced 137,300 kilograms
(about 300,000 pounds) of dates in 1897, worth 10,845 Mexican dollars.
In 1898 the production amounted only to 32,485 kilograms.
It might be supposed that northwestern Mexico would be better
adapted for growing dates than the Southwestern States, since date
culture in Sonora and Lower California has long ago passed the
experimental stage ?nd is a well-established industry. Furthermore,
in these regions there is no danger of young palms being injured by
winter cold, while from the latitude, some 5 degrees south of the
Salton Basin, the summer heat might be expected to exceed that of the
hottest deserts of California and Arizona. As a matter of fact, how-
ever, the absence of high mountain ranges and the proximity to the
Pacific Ocean and to the Gulf of California permit the sea winds to
sweep more or less freely over this whole region, thereby so reducing
the temperature and increasing the humidity that late sorts of dates
almost everywhere fail to mature on the tree and must be ripened
artificially.
Nowhere in Mexico is there any region comparable to the Salton Basin,
in California, a depression below the sea level, surrounded on two sides
by high mountain ranges which form an effective barrier to the cold,
humid winds from the ocean. b Adding to these climatic advantages,
the abundance and cheapness of the water supply, and the greater prox-
imity to markets, it becomes evident that American growers of first-
class dates have no need to fear Mexican competition. Even the
growers of second-class and ordinary dates have little cause for alarm,
for everywhere in Mexico date culture is carried on in the most primi-
tive manner, seedlings being everywhere grown and the propagation of
superior varieties by offshoots nearly or quite unknown. At present
the inferior and badly packed seedling dates produced in Mexico are
the poorest that reach our markets, and are of no importance what-
ever.
By exposure to the sun during the hot part of the day and storing indoors wrapped
up in blankets at night. (Observations of Prof. R. H. Forbes in Lower California,
communicated verbally to the writer, 1902. See p. 29. )
& Except possibly Maquata Basin, a region below sea level around the Laguna
Maquata (see fig. 10, p. 102) , in Lower California, just south of the boundary line, which
may some day rival the Salton Basin as a date-producing region, as it can be irrigated
from the Hardy River and is protected by mountain ranges on nearly all sides. It
would be very desirable to explore more fully this interesting region, which, though
adjoining our boundary, is one of the least known areas in North America.
136 THE DATE PALM.
In view of the great number of seedling dates that occur in Lower
California and Sonora, it is probable that there are among them some
valuable sorts which should be found and introduced into Arizona for
trial. Unfortunately the older trees, whose value is best known, have
long ago ceased to produce offshoots, so that such sorts can not be pro-
pagated.
PROFITS OF DATE CULTURE.
Wherever the Deglet Noor and other choice late varieties of dates
can be grown date culture will be exceedingly profitable. In a region
like the Salton Basin, California, where the winters are never cold
enough to harm seriously old date palms, where the spring arid
autumn seasons are practically rainless, preventing injury to the
flowers or to the ripening fruits, and, above all, where the summers
are always hot enough to insure the perfect ripening of the fruit, the
certainty of a crop is almost absolute, especially as the land is very
fertile and the irrigation water of good quality.
The average yield of a Deglet Noor date palm is variously put at
from 88 to 132 pounds. Counting only 75 pounds to a tree, the yield
per acre would be 4,500 pounds if the trees were planted at the usual
distance of 26f feet. Such dates, even of the second grade, sell on
our markets at from 35 to 50 cents a pound at retail when packed in
fancy boxes, and would bring probably one-quarter as much in bulk at
wholesale, or from 8 to 12 cents a pound, especially as the}^ would ripen
in the Salton Basin early enough for the Holiday markets. Allow-
ing 10 per cent for loss in packing, there would still be 4,000 pounds
of dates to the acre. Of this crop about 1,000 pounds would be of the
first grade (see p. 35), worth, say, 10 cents a pound at wholesale;
1,300 pounds would be second grade, such as now reach our markets
packed in three-quarter pound paper boxes, worth about 8-j- cents a
pound, and the remaining 1,700 pounds would be third-class dates, to
be sold in bulk at, say, 2 cents a pound, or in all some $250 worth
from one acre. The care required by the date palm is much less than
that necessary for any other fruit tree, and the fruit cures naturally
on the tree and can be gathered quickly and easily by cutting off a
whole bunch at a time. It is probable, therefore, that $100 per acre
would cover all the fixed expenses of an orchard of Deglet Noor
palms in full bearing, leaving a profit of some $150 per acre.
Offshoots bear fair crops of fruit from three to five years a after
being planted, which is but little, if any, longer than many other fruit
trees, such as the orange, fig, pear, etc., require to reach fruiting age.
The date palm comes into full bearing from eight to twelve years after
being planted, and lives to a much greater age than any other fruit
A proof of the ability of a date offshoot to fruit abundantly at an early age is
afforded by the Deglet Noor offshoot shown in Plate XXII, which was set out at
Tempe, Ariz., in July, 1900, and which when photographed in August, 1903, just
three years and one month later, bore three fair-sized bunches of fruit.
PROFITS OF DATE CULTURE. 137
tree, bearing profitable crops even when a century or more old. No
expensive pruning is required by this fruit tree, and it is remarkably
free from diseases and injurious insect pests. The amount of labor
required in a date plantation is very much less than for most other
fruit culture, and this constitutes a great advantage in its culture,
especially in desert regions, where labor is scarce and high priced.
The fruit does not ripen suddenly and need immediate care, but may
often be left on the tree for a week or two after it matures without
being injured.
It would be difficult to imagine a fruit better adapted for growing
in the Salton Basin than the choice late varieties of the date, and at
the same time a culture better suited to the needs of the country.
Although not offering promise of being so unusually lucrative as the
culture of the Deglet Noor dates, the production of good second-class
dates, comparable with the best grades of so-called Persian dates, may
nevertheless prove to be a paying industry, yielding profits equal to
those given by other fruit cultures. The Salt River Valley in Ari-
zona, which may be warm enough to permit the culture of even the
Deglet Noor dates, can certainly produce the best grade of second-class
dates, suitable for household use and serving as a substitute for Deglet
Noor dates for dessert fruit or for use in confectionery. The American
growers will have the great advantage over their rivals in the Persian
Gulf region of much greater proximity to the centers of consumption,
which will enable them to put their crop on the market earlier in the
season and in fresher condition. a
Even the growing of ordinary dates, like those sold in bulk at the
fruit stands, may prove a paying culture if carried on on an extensive
scale where land and irrigation water are cheap. Being packed
tightly together in boxes holding a hundred pounds or so, the labor of
preparing them for market is much less than for the finer dates,
which must be arranged carefully in small boxes to prevent the fruit
from being crushed or deformed by mutual pressure. The flood-plain
of the Colorado River in California and Arizona, where land that is
naturally irrigated arid fertilized by the annual overflow of the river
can be had cheaply, offers promise of being suited for the profitable
culture of such ordinary dates.
Another great advantage of American-grown dates will be their superior clean-
liness. Fairchild says (Persian Gulf Dates, p. 29), in regard to the ordinary Persian
dates of our fruit stands, "the stories which one hears in the region of the conditions
in the packing sheds and the personal uncleanliness of the men, women, and children
who put up the dates are enough to disgust a sensitive person and to prevent his
ever eating packed dates again without having them washed. No old inhabitant
thinks of eating a date without first thoroughly washing it in a glass of water, unless
the cook has prepared it beforehand, and the sale of dates in America might fall off
decidedly were it generally known how intimately the unwashed hands, bodies, and
teeth of the notably filthy Arabs often come in contact with the dates which are sold
by every confectioner."
138 THE DATE PALM.
EXTENT OF THE MARKET.
The enormous quantities of dates imported into this country every
year are a measure of the extent of the market for the cheaper grades
of this fruit. The average value of the imports of dates was $402,762
per annum for the ten years ended June 30, 1900, and the following
table gives the quantities and values of imports during the last five
years, almost entirely from Bassorah and Maskat: .
TABLE 46. Quantities and values of dates imported into the United States. 1
Year ended June 30
Quantity.
Value.
1897 .
Pounds.
11, 847, 279
Dollars.
284, 056
1898
13, 661, 434
371, 992
1899
12, 943, 305
324, 087
1900
19 902 512
410 349
1901
18, 434, 917
372, 400
1 Yearbook, Department of Agriculture, 1901.
The value per pound is very low for these common dates, amounting
to 2.06 cents in 1900 and 2.02 cents in 1901. These values are those
invoiced at the port of export, and the dates probably sell at wholesale
for at least 50 per cent more at the receiving port. a
Even at these prices it is probable that date culture would be profita-
ble if varieties that yield abundantly and regularly were planted on"
rich, naturally irrigated lands, and it is evident that the market is
practically unlimited if the cost of production can be kept low enough
to permit competition with the oriental dates.
There exists already a large market for a date of superior quality,
suitable for household uses and for emplo3 7 ment in confectionery,
while the demand for the finest grades of Saharan Deglet Noor dates
far exceeds the supply even when they are sold for more than selected
Smyrna figs. American orders fora quarter of a million pounds have
been refused by the Algerian producers because the supply barely
suffices for the European demand. The consumption of these deli-
cious dates is certain to increase as their merits become better known;
they reach the same class of consumers as Smyrna figs, and like them
can be served as a dessert fruit which can be eaten without soiling the
lingers. At somewhat lower prices a practically unlimited market
would exist for Deglet Noor dates, and the American grower would
have the great advantage over his rivals in the Sahara of being able to
gather the crop in abundant time for the Holiday trade.
Thus Mr. E. W. Maslin shows that while the average invoiced value of figs
imported into the United States is 5. 7 cents a pound, the prices brought by these figs
at auction sales in New York City range from 9 to 28 or 30 cents a pound. ( See Eisen,
G., The Fig, Bulletin 9, Division of Pomology, U. S. Dept. of Agriculture, p. 289.)
LIFE HISTORY INVESTIGATIONS. 139
IMPORTANCE OF LIFE HISTORY INVESTIGATIONS IN DEMON-
STRATING THE FEASIBILITY OF DATE CULTURE.
The importance of a detailed study of the climatic and soil require-
ments of the date palm is clearly shown in treating of the regions in
the United States adapted to its culture, as well as in the discussion of
the heat requirements and of the alkali resistance of this remarkable
plant. No other crop plant can withstand so much alkali in the soil
or in the irrigation water, and tens of thousands of acres of alkali lands
in the irrigated areas in the Southwest can be reclaimed and put to
profit only by growing dates. This renders it of the greatest impor-
tance to determine the extreme geographical limits of the regions
where dates can be produced with profit in order that this invaluable
plant may be utilized on alkali lands wherever possible.
Not only is it possible as a result of life history investigations to
indicate with some degree of precision the regions where dates can be
grown, but also to predict the types of varieties which alone can
succeed in each region, and further, to indicate in which of the date-
growing countries of the Old World such types can most likely be
secured. For example, in order to secure hardy late-ripening sorts
able to withstand the winter cold in Texas and southern Nevada,
search should be made in the oases of central Persia, near the
northern limit of date culture, where the winters are so severe that
even old, bearing palms are sometimes killed, but where the summers
are nevertheless very hot. North Africa on the contrary, is the least
promising region to search for such sorts because of the mildness
and equability of the winter climate, even in the oases situated on the
slopes of the Atlas Mountains limiting the Sahara to the north.
On the other hand, early maturing sorts, suitable for culture in the
interior valley region of California and in the flood-plain of the
Colorado River in Arizona and California, where the winters are
relatively mild and the summer heat deficient, are most likely to be
secured in just these oases on the slopes of the Atlas Mountains,
though such varieties may be expected to occur in oases at high
altitudes in the interior of the Sahara and in Arabia. Choice late
sorts of date palms, suitable for culture in the hotter valleys of
Arizona and in the Salton Basin, California, are most likely to be
found in the oases at low altitudes in the interior of the deserts of
Sahara, Arabia, and Persia.
It is also possible, from a study of the life-history factors of the date
palm, to warn intending planters against attempting its culture in
regions where it can not succeed. Thus it becomes possible to estab-
lish a new fruit industry in a rational manner without having to await
the tardy results of costly and often badly conducted trials made with-
out adequate foreknowledge of the requirements of the plant. Such
trials often lead to elusive hopes on the one hand and to unjust
140 THE DATE PALM.
condemnations on the other. To attempt to produce dates in Florida or
in the coast region of California because the date palm grows well there,
would be to commit a capital error, for no marketable dates can be
produced in climates so humid as that of Florida or so cool as that of
the California coast. To try to grow drying dates of the ordinary mid-
season or late sorts in the interior valley region of California because
the Wolf skill date palm at Winters produces every year a good crop
of palatable dates would be an error almost as disastrous, because
only very early sorts, for the most part unsuited for drying or for
export, can be matured in this region.
It is confidently to be expected that in a few years this new branch
of biologic and economic science which concerns itself with the deter-
mination of the exact requirements of crop plants as to climate and
soil, and with the finding of the limits of their powers to resist unfa-
vorable influences such as cold, excessive heat, drought, alkali, violent
winds, etc., along with a study of the cultural requirements and market
conditions of the new industry, will become so well known and its value
so well recognized that it will become a comparatively easy matter to
enlist the necessar} T capital and skill in a new culture when once detailed
life history investigations have furnished a sound basis for judgment
as to the chances of its proving a financial success in any given region.
After such studies have been made, or during their progress, a few
carefully planned demonstrations in suitable localities conducted by
the Department of Agriculture, the State experiment stations, or in
cooperation with skillful planters will take the place of haphazard
testing by experimenters, and of the usually indecisive and often enor-
mousry expensive trials b} 7 private growers.
Millions of dollars have been thrown away in attempts to grow crop
plants in regions where a properly carried out life history investiga-
tion would have shown that there was no hope of success. Unfounded
inflation of values "of agricultural lands, and the rush into new cultures
in unsuitable regions by whole communities at a time as the result of
a " boom," could largely be avoided were it possible to furnish the
would-be planter with a black-and-white statement of the necessities
of the crop plants under discussion, whereby he would be able to
question intelligently whether the region were adapted to the pro-
posed cultures.
At present it is no exaggeration to state that the life history require-
ments and the limits of the power to resist unfavorable environmental
conditions are far better known for many microscopic lower plants,
such as bacteria, fungi, and algae, even for species having no economic
importance, than for the most important crop plants whose culture
provides employment for tens of millions, and whose products consti-
tute the daily food of hundreds of millions of human beings. Such a
condition is discreditable alike to biological and to agricultural science
and should not longer continue.
SUMMARY. 141
SUMMARY.
The date palm can endure any degree of heat and any amount of
dry ness in the air, and is even favored by hot winds and by a rainless
summer. The best sorts can mature only in regions having a very
long and very hot growing season.
/ It can endure more alkali in the soil than any other profitable crop
plant and can thrive on soils containing from 0.5 to 1 per cent of
alkali, even when irrigated with brackish water containing 0.43 per
cent (430 parts per 100,000) or more of injurious alkali. It can with-
stand without injury accumulations of alkali at the surface of the soil
that would kill all other crop plants, even those considered to be very
resistant to alkali.
>< The choicest date that reaches America and Europe, the famous
Deglet Noor of the Algerian and Tunisian Sahara, is very sweet, of
exquisite flavor, and is adapted to serve as a dessert fruit; it sells for
more than Smyrna figs, being the most expensive dried fruit on our
markets. The demand for these dates during the holidays is never-
theless greater than the supply, and if they could be sold somewhat
cheaper the consumption of this fruit would be enormous.
v^The Salton Basin or Colorado Desert, in southeastern California,
recently put under irrigation, has a hotter and drier summer climate
than the Algerian and Tunisian Sahara, where the best grades of
Deglet Noor dates are grown, and is, indeed, better adapted to the cul-
ture of this fruit, since not only is the climate more favorable but the
soils are richer and the irrigation water is of better quality.
^The date palm will prove of equal value on the more alkaline areas
of other arid regions in the Southwestern States where the winters are
warm enough to permit it to grow. Most regions do not have suffi-
cient summer heat to mature the Deglet Noor date, and other sorts
which ripen earlier must be planted.
vV It is very probable that the culture of the best second-class dates,
suitable for employment in confectionery and for household uses, will
prove a profitable industry in the Salt River Valley, Arizona, and it is
possible that the Deglet Noor variety may mature there.
Even the growing of ordinary sorts, such as the oriental dates,
which are imported into this country in enormous quantities, may pay
in some favored regions, such as the flood-plain of the Colorado River
in Arizona and California, where exuberantly fertile lands can be had
cheaply, and where the annual overflow and seepage from the river
render artificial irrigation unnecessary.
\ Although date palms are likely to be grown first on soils too alka-
line for other crops, the culture of the finer sorts promises to be a most
profitable fruit industry that would warrant planting on the very best
lands and the employment of the most modern horticultural methods.
142 THE DATE PALM
DESCRIPTION OF PLATES.
PLATE I. Old date palms at Hermosillo, northern Mexico. Orange trees, peppers,
and alfalfa are growing under the palms. December, 1899. Negative by the
author.
PLATE II. Map of a portion of the Sahara Desert, in southern Algeria, showing the
principal centers of date culture, Zibane, Oued Rirh, Oued Souf , etc. Reduced from
1 : 800,000 map of Service geographique de FArrnee, Paris. Scale 1 : 2,400,000.
Localities where soil samples were secured are marked with a star. The fine
lines indicate caravan routes. The railway does not yet extend beyond Biskra.
PLATE III. Map showing distribution of soil types and of alkali in the Imperial area
in the Salton Basin, California. Prepared by the Bureau of Soils, U. S. Depart-
ment of Agriculture, in 1903.
PLATE IV. Relief map of California, showing the principal regions where dates can
be grown. Reduced from a drawing made after a photograph (furnished by
Prof. Alexander G. McAdie) of a relief map of California exhibited at the
World's Columbian Exposition, Chicago, 1893.
PLATE V. Fig. 1. Date garden in Old Biskra, Algeria. Bunches of nearly ripe fruit
are seen on the taller palms; fig trees are growing underneath in the partial
shade. August, 1902. Negative by Thos. H. Kearney and Thos. H. Means.
Fig. 2. Date palms at Old Biskra, Algeria. To left, two old male date palms,
showing more abundant leaves and thicker trunks than the female trees beyond.
Negative by the author.
PLATE VI. Fig. 1. Native gardeners (Rouara) at Ourlana, Algeria, putting date
offshoots into sacks, preparatory to shipment by camel back; to the right is seen
the corner of the date plantation. Soil samples (Ourlana, Station No. 1) were
obtained a few rods from here, May, 1900. Negative by Charles Trabut. Fig.
2. Caravan loaded with date palm offshoots for the Tempe garden, Arizona,
starting from Ourlana northward toward Biskra, Algeria, May, 1900; negative
by Charles Trabut. Fig. 3. Final trimming of date offshoots at Algiers, pre-
paratory to packing for shipment to America, June, 1900. Negative by the author.
PLATE VII. Fig. 1. Flower cluster of male date palm just emerged from sheath;
flowers opening and letting pollen escape. (One-fifth natural size.) Fig. 2.
Three female flower clusters. To left, just opening, ready to pollinate; in center,
pollinated, male twig tied fast; to right, ten days after pollination. (One-fifth
natural size.) Fig. 3. Male and female flowers of the date palm, magnified:
Above, young fruits turning green a week or so after pollination; in middle,
female flowers ready to be pollinated; below, male flowers just shedding pollen.
(Three times natural size. ) Negatives by the author.
PLATE VIII. Fig. 1. Forest of old date palms at Biskra, Algeria; an Arab has climbed
the tallest tree (in the background), and is pollinating the flowers, May, 1900.
Negative by the author. Fig. 2. Arab pollinating a date palm, Ramley, Egypt,
March 24, 1901; a rope passed around the trunk and attached to a broad belt at
the waist aids in climbing. Negative by D. G. Fairchild. Fig. 3. Arabs demon-
strating the operation of pollinating the date palm; the cluster of female flowers
is partly removed from the sheath and a sprig of male flowers is just being
inserted with the right hand; the fiber with which the flowers will be tied in
place is held in the mouth. Negative by the author. Fig. 4. Arabs demonstrat-
DESCRIPTION OF PLATES. 143
ing the pollination of the date palm; the next stage after Fig. 1 above; the cluster
of female flowers has been entirely removed from the sheath and is being tied
together with a palm-leaf fiber to hold the sprig of male flowers in place. Nega-
tive by the author.
PLATE IX. DegletNoor dates from the Sahara Desert. (Natural size.) Photographed
at Washington two months after being picked. Above, cut open date and two
seeds. Negative by G. N. Collins and the author.
PLATE X. Deglet Noor dates packed for the retail trade. The small paper box con-
tains about two-thirds of a pound; the wooden boxes hold about four and one-
half pounds. (One-third natural size.) Negative by G. N. Collins and the
author.
PLATE XI. Date palms growing in basin irrigated by flooding, at Bedrachin, near
Cairo, Egypt. The water ranges from a few inches to several feet deep and
remains standing about 6 weeks. September, 1902. Negative by Thos. H.
Kearney and Thos. H. Means.
PLATE XII. Fig trees growing under partial shade afforded by date palms in the
oasis of Chetma, Algeria; May, 1900. Negative by the author.
PLATE XIII. Date palms in garden at Biskra, Algeria. Soil samples ( Biskra, Station
No. 1) were secured in the foreground. An Arab is climbing the tall palm in
order to pollinate the flowers; May, 1900. Negative by the author.
PLATE XIV. Fig. 1. Date palms growing without artificial irrigation near Fougala,
Algeria; at the base of the palm trunks a bank or "goorma" is seen. Fig. 2.
Shallow well with sweep "kitara" used to irrigate date palms at Fougala, Algeria.
Negatives by the author.
PLATE XV. Fig. 1. Very alkaline undisturbed Saharan soil at Fougala, Algeria; a
scanty growth of salt bushes and samphires is seen in the foreground near where
soil sample (Fougala, Station No. 1) was taken; to left, in middle ground, young
palms are seen growing in pits. Fig. 2. Date palm in condition called "mez-
noon" or crazy, showing youngest leaves dwarfed and distorted; oasis of
Fougala, Algeria; May, 1900. Negatives by the author.
PLATE XVI, Fig. 1. Young date palms growing on very alkaline soil at Chegga,
Algeria. A white crust of alkali is shown along the edge of the irrigation ditch.
A soil sample (Chegga, Station No. 1) was secured nearby. Fig. 2. Young date
palms at Chegga, Algeria. A soil sample (Chegga, Station No. 2) was obtained
in the beef of oasis alfalfa seen on the left of the drainage ditch; May, 1900.
Negatives by the author.
PLATE XVII. Fig. 1. Date plantation on alkaline soil at Ourlana, Algeria, in the
Oued Rirh region of the Sahara Desert. A drainage ditch is shown and to
right ridges to facilitate irrigation by surface flooding. A soil sample (Ourlana,
Station No. 2) was secured between the first two trees on the right. Negative by
the author. Fig. 2. Crescent-shaped excavation, " dahir," at the base of a date
palm, to hold irrigation water, Biskra, Algeria. Offshoots ready to remove are
seen at the base of the trunk. Negative by the author.
PLATE XVIII. Fig. 1. View in the Salton Basin, near Imperial, Cal., looking south-
ward, showing level, bare desert land, with almost no trace of vegetation; Signal
Mountain, in Mexico, in the distance; January, 1901. Fig. 2. Shore of a dry,
salt lake, Chott Merouan, between Chegga and M'rai'er, Algeria, with salt-loving
vegetation; in the distance a mirage simulates a vast sheet of water, with remote
islands covered with bushes. Negative by the author.
PLATE XIX. Fig. 1. A neglected Egyptian date palm growing without irrigation in
the Salton Basin, near Indio, Cal., November, 1899. Fig. 2. Old date palms
showing reflexed, dead leaves growing at Hermosillo, northern Mexico; orange
144 THE DATE PALM.
trees grow under the palms; arid hills form the background; December, 1899.
Fig. 3. Fan palm, showing persistent dead leaves clothing the trunk, near Indio,
Cal. Fig. 4. Group of fan palms growing wild in a dry ravine near Indio, Cal.,
November, 1899. Negatives by the author.
PLATE XX. Fig. 1. Old date palms growing at San Diego Mission, near San
Diego, Cal. Negative by Park & Co., Los Angeles. Fig. 2. Seedling date palm,
showing bunches of nearly ripe fruit, growing without artificial irrigation in the
flood -plain of the Colorado Biver, near Yuma, Ariz. ; planted by Mr. Hall Han-
Ion (who stands beneath), November, 1899. Negative by the author.
PLATE XXI. View in Cooperative Date Orchard at Tempe, Ariz., showing growth
made in two years by offshoots imported from North Africa in 1900. Photo-
graphed December 31, 1902, by Prof. R. H. Forbes.
PLATE XXII. Three-year-old Deglet Noor date palm in fruit, growing in the Coop-
erative Date Orchard at Tempe, Ariz., from an offshoot imported from the Sahara
Desert in July, 1900. Photographed August 27, 1903, by W. W. Skinner.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE V.
FIG 1. FRUITING DATE PALMS AT OLD BISKRA, ALGERIA, WITH FIG TREES GROWING
UNDERNEATH, AUGUST, 1902.
FIQ. 2. DATE PALMS AT OLD BISKRA, ALGERIA. Two LARGE MALE TREES AT LEFT.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture,
PLATE VI.
FIG. 1. NATIVE GARDENERS (ROUARA) AT OURLANA. ALGERIA, PREPARING
DATE OFFSHOOTS FOR SHIPMENT BY CAMEL BACK.
FIG. 2.-
-CARAVAN LOADED WITH DATE PALM OFFSHOOTS FOR ARIZONA,
STARTING FROM OURLANA NORTHWARD, MAY, 1900.
FIG. 3. FINAL TRIMMING OF DATE OFFSHOOTS AT ALGIERS PREPARATORY
TO SHIPMENT TO AMERICA, JUNE, 1900.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE VII.
FIG. 1. FLOWER CLUSTER OF MALE DATE
PALM JUST EMERGED FROM SHEATH AND
LETTING POLLEN ESCAPE.
FIG. 2. THREE FEMALE FLOWER
CLUSTERS.
FIG. 3. MALE AND FEMALE FLOWERS OF THE DATE PALM, MAGNIFIED.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE VIII.
FIQ. 1. FOREST OF OLD DATE PALMS AT
BISKRA, ALGERIA, SHOWING ARAB POL-
LINATING FLOWERS.
FIG. 2. ARAB POLLINATING A DATE PALM
RAMLEY, EGYPT, USING A ROPE AND
BROAD BELT IN CLIMBING.
FIG. 3. ARABS DEMONSTRATING THE POL-
LINATION OF THE DATE PALM. SPRIG OF
MALE FLOWERS BEING INSERTED.
FIG. 4. CLUSTER OF FEMALE FLOWERS
BEING TIED TOGETHER TO HOLD THE
SPRIG OF MALE FLOWERS IN PLACE.
Bui. 53, Bureau of Plant Industry, U. S. Dept of Agriculture.
PLATE IX.
DEGLET NOOR DATES FROM THE SAHARA DESERT (NATURAL SIZE).
Jul. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE X.
, v
DEGLET NOOR DATES PACKED FOR THE RETAIL TRADE.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE XI.
DATE PALMS GROWING IN BASIN IRRIGATED BY FLOODING AT BEDRACHIN, NEAR CAIRO,
EGYPT, SEPTEMBER, 1902.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE XII.
FIQ TREES GROWING UNDER PARTIAL SHADE AFFORDED BY DATE PALMS, OASIS OF
CHETMA, ALGERIA.
Bui. 53, Bureau of Plant Industry, U. S Dept. of Agriculture
PLATE XIII.
ARAB CLIMBING TALL PALM IN A GARDEN AT BISKRA, ALGERIA, TO POLLINATE THE
FLOWERS, MAY, 1 900.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture. PLATE XIV.
FIG. 1. DATE PALMS GROWING WITHOUT IRRIGATION NEAR
FOUGALA, ALGERIA.
FIG. 2. SHALLOW WELL USED TO IRRIGATE DATE PALMS AT
FOUGALA, ALGERIA.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture. PLATE XV.
FIQ. 1. VERY ALKALINE UNDISTURBED SAHARAN SOIL AT FOUGALA,
ALGERIA. YOUNG PALMS GROWING IN PITS.
FIG. 2. DATE PALM IN DISEASED CONDITION CALLED "MEZNOON,
CAUSED BY EXCESS OF ALKALI, FOUGALA, ALGERIA.
Bui 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE XVI.
FIQ. 1. YOUNG DATE PALMS GROWING ON VERY ALKALINE SOIL
AT CHEGGA, ALGERIA.
FIG. 2. -YOUNG DATE PALMS AND SAHARAN ALFALFA AT CHEGGA,
ALGERIA.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE XVII.
FIQ. 1. DATE PLANTATION ON ALKALINE SOIL AT OURLANA, ALGERIA.
FIG. 2. CRESCENT-SHAPED EXCAVATION AT THE BASE OF A DATE PALM TO HOLD
IRRIGATION WATER, BISKRA, ALGERIA.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture
PLATE XVIII
FIG. 1. VIEW IN THE SALTON BASIN, NEAR IMPERIAL, CAL., SHOWING LEVEL, BARE
DESERT SOIL.
FIG. 2. SHORE OF A DRY SALT LAKE, CHOTT MEROUAN, BETWEEN CHEGGA AND
M'RAIER, ALGERIA.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE XIX,
FIQ. 1. A NEGLECTED EGYP-
TIAN DATE PALM GROWING
WITHOUT IRRIGATION IN THE
SALTON BASIN, NEAR INDIO,
CAL.
FIG. 2. OLD DATE PALMS AT HERMOSILLO, NORTHERN
MEXICO, WITH ORANGE TREES GROWING UNDERNEATH.
FIG. 3. FAN PALM SHOWING DEAD LEAVES
CLOTHING TRUNK, NEAR INDIO, CAL.
FIG. 4. GROUP OF FAN PALMS GROWING
WILD IN A DRY RAVINE, NEAR INDIO, CAL.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture,
PLATE XX,
FIQ. 1. OLD DATE PALMS GROWING AT SAN DIEGO MISSION, NEAR SAN DIEGO, CAL.
FIG. 2. SEEDLING DATE PALM WITH NEARLY RIPE FRUIT, GROWING WITHOUT IRRIGATION
IN THE FLOOD PLAIN OF THE COLORADO RIVER IN CALIFORNIA.
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE XXI.
o
Bui. 53, Bureau of Plant Industry, U. S. Dept. of Agriculture.
PLATE XXII.
THREE-YEAR-OLD DEGLET MOOR DATE PALM IN FRUIT, GROWING IN THE COOPERATIVE
DATE ORCHARD AT TEMPE, ARIZ., FROM AN OFFSHOOT IMPORTED FROM THE SAHARA
DESERT IN JULY, 1900. PHOTOGRAPHED AUGUST, 1903.
ND.EX.
Page.
Aeration, imperfect, danger in date culture, note 121
necessity to roots of date palm 50
of soil about date palm, effect, notes 78, 80
importance in irrigation of dates 47
Age. See Bearing age.
Al Shelebi, Medina date, description 40
Alfalfa, killing by alkali near date garden at Tempe, Ariz., note 100
Saharan, as crop in alkaline soil in date orchard 23, 87, 115
Algeria, alkali conditions in relation to date culture 76-99
bearing age, continuance and yield of date palms 26
Fougala, unusual drainage conditions in date growing 51
irrigation of date with warm water, remarks 49
M'Zab date region, valuable dates 37
records of atmospheric humidity and rain in date regions 55
shipment of date offshoots to Arizona 21, 42
sum of mean maximum temperature in date season 68
sum of mean temperatures in date region 66
temperature curves in date region 63-64
Alkali at Palm Canyon, near Sal ton Basin, date region Ill
black, effect on plant roots and on humus 1 01
resistance of date palm 119-120
cause of disease of dates 116, 120
comparison in water and soil at two Algerian stations 95
crops resistant, notes 23, 87, 115, 121
destruction of young date plants, and remedy therefor 21
effect in clay soil, note 109
on seedling date palms, caution 18
electrical determination in soil 75
excess, effect on date palm 79, 83, 116, 120
explanation of term in connection with date culture 72
freedom of land near Colorado River 130
in Colorado River water, remarks 1 05
relation to date culture in Salt River Valley, Ariz 99-101
soil at Fougala, Algeria, graphic representation 81
resistance of date palm, note 11
soils, study and analyses to determine amount 73
surface soil, relation to date growing 117
injury to date palms in Sahara - 83, 86, 118
nitrates in Sahara; in Salton Basin 85, 113
relation to date culture in Salton Basin, Cal 101-114
removal by irrigation and drainage 78
resistance of date palm 72-121
importance, remarks 76
limits -- 115-121
summary 141
rise, possible benefit to date palm ' 117
Salton Basin, chemical composition 112
treatment for modification in date culture 47
Alkaline lands, superior value of date for cultivation 121
soils from Sahara, analyses other than in present publication 97
subsidiary cultures with date plantations 115
water, use in irrigation of date palm 50
Amaree, early date, note 31
13529 No. 5304 10 145
146 THE DATE PALM.
Page.
Amreeyah date, note 129
Analyses of Saharan soils for alkali, method 73
soils and waters of date regions for alkali, tables 76,
77,80,82,83-89,91-98
in Arizona for alkali 100
Salton Basin, Cal., for alkali 107-113
Arab cultivators, management of date palm offshoots 15
Arabia, dates of promise for United States 40
Khalas date from Hassa. .. 36
Arabs, date cultivation, notes 17
drying and packing of dates 30
planting of date palm, notes 22
practice of keeping pollen 28
skill in climbing date palm and pollinating flowers 27
watering of young date palm offshoots 21
Areshtee date, large yield, note 26
Arid regions of Southwest, suitability for date growing 11
United States. See Arizona, California, etc.
Arizona, amount of water needed in irrigation of date 46
atmospheric humidity, records 53
bearing age of date palm 25
character of male dates 20
cooperative date garden, notes 41, 128
date culture, probable success 126-133
prospects 13
dates to be secured 38
varieties, very large collection at date garden 128
early importation of dates 41
growing of dates, present 32, 128-129
insufficiency of heat for seedling dates, note 18
notable yields of dates 26
number "of male date palms, note 23
peculiarity of cold air drainage in relation to date 61
profits of date culture, estimates 137
rainfall, records 53, 55, 56, 57
ripening of Deglet Xoor date, doubtfulness 67
Salt River Valley, alkali character, remarks 101
in relation to date culture 99-101
second importation of date offshoots 42
seedling dates of value 32, 128-129
summer temperatures, sum 66
Tempe and Salt River Valley, drainage problem 51
introduction of Dakar male date palm. 24
planting of Deglet Noor dates 35
temperature variations 50, 00
temperatures, mean and mean maximum, sums 66, 68
University, establishment of date garden 41
warmth o'f water in irrigation of dates
Yurna, climatic peculiarities, relation to date growing 50
Artesian wells in Salton Basin, proposed use for irrigation Ill
irrigation in Algeria, remarks; analysis of water 90, 91
of date palms " 121
use in irrigation of date in Sahara, notes 44, 45, 79, 82, 84
warm water for irrigation of dates 49
Assyrians, cultivation and use of dates
discovery of pollination of dates 26
Atriplex semibaccata" saltbush, resistance to alkali 121
Bagdad, dates of promise for United States 39-40
Baluchistan, dates and date region
Barley as crop in alkaline soil in date orchard 23
resistance to alkali, note 115
Barrows, David P., remarkson Colorado desert 103
Bassorah, date exports, notes - x
soil and cultivation 109
Bearing age of date palms, discussion; note 25, 136
continuance, of date palm 26
INDEX. 147
Page.
Ben Chabat, Arab, remark on distance apart in planting date palms 22
Bent Keballa date, notes 32, 37
Bennet date, notes 32, 128
Biskra, Algeria, alkali conditions in relation to date culture; clay soils. . . 76, 77
date region, temperature curves 63-64
evaporation records ; irrigation practice 46, 47
Black alkali. See Alkali.
Blooming of date trees, season and manner (see also Flowering) 16, 27, 54
Botanical relations and characters of date palm 14-16
4 ' Boussaafa' ' or ' ' Meznoon' ' disease of date from alkali 116
Briggs, L. J. , devising of instrument for determining soil moisture 75
BuHafs date, note 39
Bud of date palm, importance 14
Burton, Pilgrimage to Mecca, remarks on dates 40
Calcium sulphate and chlorid, relations in soil water of Sahara 74
Calexico, outlook for date growing, notes 104, 108
California and Arizona, rainfall and irrigation (see also Salton Basin) 49
date culture, probable success 122-125
fig growing, remarks 14
Lower (Mexico) , date production 135
peculiarity of cold-air drainage in relation to date culture 61
Salton Basin, conditions favorable to date growing 12
seedling dates, experiments 20
Camels, relation to date culture in Sahara 17
Canary Island palm, possible use in hybridizing 125
Carbonates in Salton Basin soil, showing of analyses 112, 113
soil in Arizona as shown in analysis 100
resistance of date palm 119
Chegga, Algeria, comparison of soil and water with Ourlana, Algeria 95
Chlorids in Salton Basin soils 112, 113, 114
soil in Arizona, as shown in analyses 100
maximum and injury, in Sahara, note 87
resistance of date palm 118
Clay soil, alkali, effect on date palm 109
soils, use for dates, notes 77, 108, 109
Climate, California, relation to date culture 122-125
conditions favorable for date growing, notes 11
for date palm, humidity 52-58
sunshine and heat 58-70
summary 141
for date palm, ideal 56
hot summer, advantages for date growing 63-70
of Salton Basin, remarks 112
Coachilla date, seedling, description 31
Coast region, southern California date culture, chances of success 125
Cold, effect on date (see also Climate, Temperature) 21, 49, 59, 60, 61, 133
Colorado Desert. See Salton Basin.
River flood, effects 50,103,105,129
peculiar climatic conditions, relations to date growing 50
quality of water, remarks 105, 106
Valley, date culture, probable success 123, 129-133
Yuma, similarity in alkali to Sahara 87
Cook, O. F., report of dates in Morocco and Liberia 39, 97
suggestion as to use of dry dates 31
Crop plants, resistance to alkali, limit, note 121
Crops, garden and field, in vacant space in date orchard 22
with dates on alkali soils, remarks 115
Cuinet, note on Khalas date 36
Cultivation of date, suitable climate and soil; work required 11, 25
Curing, gathering, and packing dates 29-30
Dakar majahel, male date palm, introduction and value for pollination 24
Date, Bearing, age 25, 136
culture, importance of life history study (see alxo Date growing) 139-141
in western Zab, peculiar system 78
Mexican competition, freedom from danger 134-136
148 THE DATE PALM.
Page.
Date, culture, profits (sec also Date growing) 136-138
regions of United States of probable success 122-125
(fruit), description 17
garden, cooperative at Tempe, Ariz 42, 128
experimental at Mecca, Cal 110
gardens, sunken, of Souf country, Sahara, remarks 69
growing, care of tree, pollination, gathering, curing, and packing dates. . . 25-30
in United States, types and varieties of dates suitable 30-44
season, water supply in Salton Basin 105
thinning of bunches on tree (see also Date culture) 28
palm, alkali resistance, discussion 115-121
amount of water necessary in irrigation 44
and dates, care, discussion *. 25-30
general remarks on conditions in United States 11-13
areas in Salton Basin for growing 110
as shelter for other fruit trees 43
destruction by rain at Moorzook, Fezzan, Sahara 118
drainage, discussion . . ., 50-52
effect of excess of alkali 79, 83, 116, 120
effects of atmospheric humidity and rain, discussion 52-58
wind, discussion 70-72
heat requirements, discussion 58-70
irrigation, discussion 44-50
necessity of sunshine, and heat requirements 58
offshoots, successful shipment 20-21
propagation 18-25
resistance to alkali 72-121
usefulness and botanical characters, etc 14-17
plantations on alkaline soils, subsidiary cultures 115
variation of heat requirement for different sorts 63
varieties for cultivation in Arizona 32, 128, 129
Dates, early sorts from Sahara for United States 32
finest grades, shortness of supply 138
gathenng, caring, and packing 29-30
of commerce, varieties, remarks 38
importance for United States, names and notes 39, 40
ordinary, probable success of culture; summary 132, 142
Persian Gulf, importation into United States, note 132
promising varieties introduced into United States 37
Saharan, importation into United States 41
soft and dry, notes 20
types, three, remarks 30-31
De Candolle, statement of lowest temperature for date palm 63
Death Valley, date culture, chances of success 122
Deglet Noor date, certainty of ripening in Salton Basin 67
derivation of name 36
disease, Boussaafa 116
high quality, summary 33, 141
notes. 30, 41, 58, 63, 68, 69, 70, 89, 110, 116, 122, 123, 128, 133, 136, 137
quality, grades, prices, yield, requirements in growing, etc. . 33-36
Salt River Valley, for growing 128
Salton Basin, for growing 67
shortness of supply. 138
yield, prices and profits 136
Desert regions, records of rainfall (see also Sahara, etc. ) 57
Disease, date palm, from alkali 116
' ' Merd el Ghram ' ' due to bad drainage 120
freedom of date palm 137
Distances between trees in planting dates 22
Drainage, bad, cause of disease in date palm 120
connection with irrigation in Sahara 78, 86
for the date palm, discussion 50-52
in Colorado Valley, necessity except in date culture 131
use in Salton Basin in date culture, note .' . 110
value in alkali lands for date culture, note 73
w r ater from alkaline soils, irrigation of date in Sahara 98
"Dry dates," description 31
INDEX. 149
Page.
Egypt, dates, notes '32,39,41,129
irrigation by flooding, remarks 48
Egyptians, ancient, cultivation of date, notes 17
Electricity, use in soil investigations, notes 75, 79
Evaporation, relation to irrigation of dates 46
Exportation of dates, manner and importance 14
Fairchild, D. G. , description of irrigation and drainage system 48
observation of date soils on Persian Gulf 109
packing dates on Persian Gulf 137
opinion as to Bagdad, Khalas and Mozaty dates 37, 38, 40
Fan palm in Salton Basin, fruit like date; alkali resistance Ill, 112
Fard date, exports to United States, note 38
Female flowers of date, description and method of pollination 27
differences from male flowers 19
Fig growing in California, reniarks 14
under date palm 44
Fischer, Th. , calculations of temperature for date flowering 64
remarks on Mozaty date 37
Flooding as method of irrigation, probable value in date growing 48
Flower clusters of date, description and number 26-27
Flowering of date palm, lateness as safety from frost (see also Blooming) 61
lowest temperature limit 63
Flowers and fruit of date, disastrous effect of rainy weather 54
date, effect of pollination on value of fruit 28
of date palm, male and female, growth; distinguishing marks 16, 19
Forage crops with dates on alkali soils, notes 115
Forbes, Prof. R. H. , experience with date palms in alkali soil 18, 21, 42
observation on date palm roots 112
ripening of dates, artificial, method 135
Rhars date, observation 32
study of water and irrigation 99, 105
Fougala, Algeria, alkali in relation to date culture 78-84
French, planting of date palm in the Sahara, notes 22
Fritsch, G. , conclusion as to germination of date 19
Frosts, escape of date by late flowering 61
Fruit and flowers of date, disastrous effect of rainy weather 54
date, heat required for maturing 65-70
of date palm, need of dry air for proper development 52
.trees, shelter of date palm 43
Fruiting of date palm, effect of pollination on value of date 28
lowest temperature limit 63
necessity of high temperature 62-65
Fruits for growing, with dates on alkali soils, notes 115
Fukus date, note 39
Gardens, date, experimental in Arizona and California 42, 110, 128
sunken, of Souf, Sahara, description 69
Gathering, packing, and curing dates 29-30
Geography and geology of Salton Basin, California 101
Geological Survey, estimate of irrigable lands on Colorado River 130
Geology and geography of Salton Basin, California 101
Germination of date palm (seed), need of water 19
Gila Valley, Arizona, date culture, probable success, notes 126, 133
Gypsum in Saharan soils, note 73
solubility in soil moisture 74
use in reclamation of black alkali lands 119
Habitat, natural, of date palm, indications ' 19
Malawi date, note 38
Hamraya date, note 26, 37
Hanlon date plantation, climatic peculiarities 50
Hardpan, drainage in date lands 51, 78
Hayani date, note 32
Heat, amount required to mature date (see also Temperature) 65-70
requirements of date palm, discussion 58-70
History of date cultivation, remarks 17
150 THE DATE PALM.
Page.
Honey, date, production and use 30
Humidity, atmospheric, and rain, effect 011 date palm 52-58
exceptionally low in Sahara 70
Hybridizing, plant breeding, remarks 24, 98, 125
Ibn-el-Fasel, Andalusian Moor, note 72
Imperial soils, Salton, Cal., value for date 107-110
Importation of date palms and dates 35, 41, 132
Indians, Coahuila, tradition as to Salton Basin 103
Irrigation, areas of promise in Colorado River Valley 130
date, amount and application of water in United States 46
growing without use 131
in alkali desert, Algeria 78-80
palm, discussion 44-50
use of drainage water 98
with alkaline water, note * 50
earlier ripening of date by use of warm water 67
lack of water in Death Valley 123
of date lands in Salton Basin, notes , 108, 110
Salton Basin, history and progress 104
water for dates, advantages of warmth 49-50
Iteema date, note 37
Juice of date, draining off and preservation 30
Jus, M., estimate of water necessary for date palm 44
Kales date, note 128
Khadrawi date, note 38
Khalas date, quality, description, etc 36-37
Leaves, date palm, description, habit of growth 15
toughness and resistance to wind 71
use as shade 13
Life history investigations, importance in new crops, notes 139, 140
Loam soil, use for dates, notes 107, 108
Loozee date, note 26
LountNo. 6, date, notes 32, 128
Magnesium chlorid, preponderance in Ourlana (see also Alkali) 94
sulphate, high content in soil at M'rai'er, Algeria 89
Maktumdate, notes 39, 40
Male date palm, characteristic differences from female 25
pollination, chief requisite 24
palms, varieties, remarks 24
trees, proportion in planting 23
flower of date, differences from female flower 19
flower cluster of date, description , 26
Maquata Basin, Mexico, date growing, advantages 103, 135
Market and prices in United States for Deglet Noor dates 34
for dates in United States, extent .' 138
Maskat, exports of dates, notes 38, 41
Masselot, F., publications, references 26, 36
Maturity. See Ripening.
McClatchie, Prof. A. J., notes on date culture 129
Means, Thomas H. , analyses of date soils
Menakher date, quality, and need for trial in United States
' ' Merd el Ghram ' ' disease of date palm due to overirrigation 120
Mexican competition in date culture, improbability 134-136
Mexico, date culture, packing and production 41, 135
region, probable 103
insufficiency of heat for seedling dates, note .
male date palms, character and number, notes 20-23
"Meznoon" or "boussaafa" disease of dates 116
Mirhage date, notes 39, 40
Mohave Desert, date culture, chances of success 123
Moors, introduction of date growing into Spain 17
Moorzook, Fezzan, Sahara, effect of rain on date 118
INDEX. 151
Page.
Morocco, excellence of dates, remarks 39, 40
Mozaty or Mazauty date, note 37
M'rai'er, Algeria, alkali in relation to date culture 88
Mulch, use in propagation of date, note 22
M'Zab, Algeria, dates 37
Nevada, date culture, probable success 125-126
kind of date required 33
New Mexico, date culture, probable success 133
Nice, date palm, ripening of fruit, notes 124, 125
Nitrate in Salton Basin soil, value and use 114
Nubia, dates of promise for United States 40
Offshoots, date, packing, and shipment, innovation by writer 42
loss of seedling date varieties by too close trimming 25
propagation of date palm 20
reproduction of date palm 15
Olive trees, protection of date palm 43-44
Orange orchards, Riverside, Cal. , injury by alkaline waters 121
Orchards, date, scientific starting (see also Offshoots, Propagation, etc. ) 25
seedling date, advisability of planting in Salton Basin 18
Oued Rirh, Algeria, date culture, remarks 89-90
Ourlana, Algeria, alkali in relation to date culture 89-95
Packing, gathering, curing of dates 29-30, 33, 137
offshoots (young date plants) for shipment, innovation by writer ... 42
Palgrave, W. G., remarks on Khalas date 36
Palm. See Date palm.
Pangh Ghur region in Baluchistan, dates 1 . 37
Persia, dates of promise for United States 40, 126, 134
Persian Gulf, date, damage by " shamel" wind 71
region, soil 109
dates, imports into United States, note 132
packing 137
tidal irrigation 48
oases, possible source for dates useful in Nevada and Texas 126
Phoenix canariensis, possible use in hybridizing date 125
reclinata (?) native growth and use in hybridizing 98
Phosphoric acid of Colorado River water, benefit to Salton Basin soil 106
Pit. See Seed.
Plant breeding, hybridizing, remarks 24, 98, 125
Plant introduction, early maturing dates 133, 139
Planting and care of date palm offshoots 21
of date orchard, distances between trees 22
number to acre in desert, notes 45
proportion of male trees 23
seed, remarks 18
Plateau region, California, date culture, chances of success 123
Pollen of date, effect of character on fruit 24
shipment 29
Pollination, importance of labor, and ease for young trees 29
need of simplification of method 28
of date, difficulties 27,28
palm, discussion 26-29
dates, origin and practice 16
supply of male trees 23, 24
practice of Arabs in keeping pollen 28
value of Dakar majahel, male date palm, at Tempe, Ariz 24
Pomology, Division, early importation of date palms 41
Potassium chlorid in Salton Basin soil, value 1 14
Prices of dates, remarks '. 136-138
Profits of date culture 136-138
Propagation of date palm by offshoots -. 20
. seedlings 18
discussion 18-25
. proportion of male trees in plantations 23
dates, failure of seedlings in trueness to type 19
Pruning of date palm, trimming off of leaves 15, 25
152 THE DATE PALM.
Rain and atmospheric humidity, effects on date palm, discussion ............ 52-58
at Moorzook, Fezzan, Sahara, destruction of date ....... . ........... _. . 118
in Death Valley, lack ................................................ 123
injury to flowers and fruit of date palm ................... ............ 54
notes on amount at various date-growing points ...................... 57
Rainfall, sufficiency, for dates in parts of California and Arizona (see also Rain ) 49
Rainy days and rainless months in date regions, records . ................... 56
Reproduction of date palm in natural state ................................. 15
Rhars date, good qualities ........ ....................................... 32, 33
notes ................................................. 30, 41, 50, 132
Rohlfs, Gerhard, remark regarding dates in Morocco ......... . .............. 39
Ripening of dates, artificial, method ....................................... 135
benefit of hot dry wind ................................. 71
hastening by use of warm water in irrigation ............. 67
heat requirement ....................................... 65-70
Deglet Noor date, remarks ................................. 67, 68, 69
Rirh River. See Oued Rirh.
Rolland, M. , estimate of water supply for date _____ ......................... 45
Roots of date palm, characteristics ......................................... 19
depth in alkali soil .................................... 112
moisture in earth, necessity ............................ 46
need of aeration . ...................................... 50
offshoots starting after planting ........................ 21
trimming in transplanting ............................. 20
fan palm in alkali, remarks ..................................... 112, 119
Rose, M. le commandant, estimate of water supply for date .................. 45
Sacramento and San Joaquin valleys, date culture, probable success ......... 123
Sahara, comparison of water supply with Colorado River ................... 105
dates and date palms .......................................... 39, 40, 41
importance of date growing .............................. ......... 17
investigation of alkali-resisting power of date palm .................. 73-99
protection of fig and olive by date palms ........................... 44
ratio of male date palms, note ..................................... 23
season of flowering of date ........................................ 27
Souf country, growing of Deglet Noor dates ........................ 35
sunken date gardens, description ..................... 69
study of alkali resistance of date palm ........................... 115-120
temperature curves in date region. . ................................ 63-64
temperatures, mean and mean maximum ........................... 66-68
Saharan alfalfa, use on alkaline soils in date orchard ........................ 23
varieties of date palms, introduction into United States ............. 41-43
Salt River Valley, Ariz., alkali in relation to date culture (see also Arizona) . . 99-101
climatic conditions for date .................... 53, 55, 57
date culture, probable success ..................... 127
irrigation water, temperature and -composition ---- i 49, 99
seedling dates ........................... ....... 32, 128
Saltbush, Australian, resistance to alkali ........................... I ..... 115, 121
Saltoii Basin, Cal. , alkali as compared with Algeria ........................ 93, 113
character ...................................... '. . 101
conditions in relation to date culture ........ ---- 101-114
amount of water needed for irrigation of date, note ....... 46
artesian wells .......................................... Ill
chemical composition of alkali ................ , ....... 112-1 13
climate, remarks ............................... - ....... 112
culture of Deglet Noor dates .............. 33, 65, 67, 69, 110, 136
crop growing by Indians in early days ...... . . ........... 103
danger, possible, to date from cold ...................... 72
date culture advantages, summary ....................... 141
probable success . .......... ..'. 5, 12, 33, 67, 122, 136
growing areas .................. - .................. 110
dates to be secured .....................................
distribution of alkali, by depths ....................... 117-118
drainage for date growing, remarks ..................... 51-52
experimental garden at Mecca .......................... 110
fan-palm oases ......................................... HI
fertility of soil ...................... r .................. 114
INDEX. 153
Page.
Salton Basin, Cal., geography and geology 101
irrigation and water supply 12, 104
name, use 12
need of late sorts of dates, note 43
opening for date culture 33
Palm Canyon, comparison of soil with Sahara 112
profits of date culture, estimates 136
record of rainless months 56
region, promising, for date 67, 122
seedling date orchards, advisability of planting 18
similarity of conditions to Fougala, Algeria 83
to M'rai'er and Oued Birh regions, Sahara 88, 111
sum of mean maximum temperatures. < 68
mean temperatures 66
temperature curves. 63-64
treatment of alkali land in date culture 47
variation in temperature 59, 60
warmth of water for irrigation of dates 50
winter cold greatest danger to date 60
San Diego, date, failure to ripen 125
Joaquin and Sacramento valleys, date culture, probable success 123
Sandy soil, usefulness for dates, notes 107, 108
Sayer date, note
Schweinfurth, Dr. Georg, claim as to influence of male date on seed
Season for setting out date palm offshoots ^ 21
of flowering (bloom) of date 16, 27, 54
male date palm, relation to pollination 23
Secretary of Agriculture, inauguration of date study and introductory plantings 41
Seed and Plant Introduction anjd Distribution, Office, aid in study of date 41
of date, peculiarties of germination 19
Seedling date palms, growing near Yuma, Ariz 131
management in nursery, suggestions 19
dates, failure of reproduction true to type, note 19
in Arizona 32,128
of Mexico, probable value in United States 136
palms in propagation of date, discussion 18-20
Seeds of date, Deglet Noor, notes 33
importance to value of fruit 28
varietal characteristics 24
Seewahdate, note 32,61,129
oasis, origin of wahi date, note
Seidell, Atherton, analysis of Sahara soils for alkali 73
Setting out date palm. See Planting.
Sex of date palm, determination 29
"Shamel," hot wind of Persian Gulf, damage to dates 71
Shelter, for other fruit trees, value of date palm 43
Shipment of date palm offshoots, success 20-21
Simoons, effect on date palm 70-71
Sirocco, effect on date palm 70-71
Sodium sulphate, relations in soil water in Sahara 74
"Softdates," description 30
Soil conditions in Salton Basin, discussion 106-111
moisture, means of determining in study for date palm 75
reaction in relation to date culture ~ 119
samples near Palm Spring, Cal. , analysis Ill
Soils, Bureau, relation to date growing of researches in Salton Basin, Cal 12
study of soils of Sahara for alkali, cooperation 73
of Sahara, investigation of alkali in relation to date culture 73-99
Salton Basin, analyses; fertility 113, 114
results of analyses at ten Saharan stations 96
Tempe, Ariz., analyses '. 100
used in date raising on Persian Gulf 109
water content in relation to alkali 75
Spain, introduction of date growing 17
Springs and wells, irrigation of dates in alkali deserts, Algeria 78-80
Subsoil, alkali, importance in date growing 116
Suckers. See Offshoots.
154 THE DATE PALM.
Page.
Sulphates, in Sahara in soils, notes (see also Analyses) 73, 87
Salton Basin soil, showing of analyses 112, 113
soil in Arizona, as shown in analyses ".. 100
resistance of date palm 87, 119
Sultani date, note 40
Summers, hot, necessity for date culture 63-65
Sunshine, necessity for date palm 58
Table dates, remarks .. 30
Tafi let, Morocco, excellence of dates, note 39
Taylor, Col. Sam., experiments with seedling date trees 20
Teddala date, notes 32, 33, 37, 132
Tedmama date, note 32
Tempe, Ariz. See Arizona.
Temperature curves for date regions 63
heat requirements of date palm 58-70
high, necessity for fruiting of date 62
inversion by cold-air drainage, relation to date culture 61
limits of cold for date palms of varying age 60
low, cold-air drainage, cause of injury to date 61
endurance by date palm 59-60
mean annual range in several date regions 59
relation to growth of date fruit 52
Temperatures, sums for date season at various desert stations 66, 68
Tennessin date, note 32
Texas, kind of date required 33, 61
southwestern, date culture, probable success 134
Thermometer, need of device for finding date needs exactly 67
Thinning date bunches on tree, remarks 28
Tidal irrigation of dates, remarks 48
Timjooert date, notes 32, 37
Tourney, Prof. James W. , study of date in Arizona 41, 127
Trimming. See Pruning.
Tunis, dates, suitable varieties for use in United States 133
male date palm for late pollination 24
United States, dates suitable for culture, discussion 30-44
importation of dates 14, 138
introduction of Persian Gulf and Saharan varieties of dates 41-43
names and notes on dates of promise 39, 40
regions of probable success of date culture 122-125
southwestern, importance of hardy dates 61
varieties of dates to be secured 38
Wahi date, origin, quality, description 39
Warm irrigation water for dates, advantages, discussion 49-50
Water, alkaline, use for date palms 44, 52, 121
amount needed for date palm, discussion 44-49
artesian, irrigation of date palm 82, 84, 90
Colorado Kiver, use for dates; composition 50, 105
drainage, use in irrigation of date palm 98
Salt River, composition 99
warm, advantage for irrigation of date palm 49-50
Weather, California, relation to date culture (see also Climate) 122-125
rainy, disastrous effect on flowers and fruit of date 54
Weevils, attacks on dates 31,39
Wells and springs, irrigation of dates in alkali desert, Algeria 78-80
Wheeler, Prof. H. L., experiments as to soil reaction, note 120
Whitney, Prof. Milton, attention to analyses of date soils 11, 73, 111
devising of instrument for determining soil moisture 75
Wind, effects-on date palm, discussion 70-72
pollination of date palm in wild state 26
Winds, cold, effect on date culture in Algeria and Persia 71-72
prevention of date culture on California coast 124, 125
Salton Basin, protection by mountains 101-103
sea, effect on date ripening in Mexico 135
INDEX. 155
Page.
Winter, resistance of date palm to cold 59-60
Wolfskil 1 date, failure in reproduction by seedlings 20
notes 31,49,63,124
Yield of date palms in pounds, and continuance of bearing 26
dates, remarks 136-138
sunken gardens, and value of trees 70
Deglet Noor date 35
Hamraya date 37
Yuma, Arizona. See also Arizona arid Salton Basin.
advantages for irrigation 87
date culture, conditions 131
9
Zab, Western, date region in Sahara, description, etc 78
Zero point for date culture 63-64
o
[Continued from pain- '2 of cover.]
No. 21. List of American Varieties of Vegetables for flu- Years 1901 and 1902. 1903.
Price. 35 cents.
22. Injurious Kffects of Premature Pollination. IDOL*. Price, 11) cents.
23. Berseem: The Great Forage and Soiling Crop of the Nile Valley. 1902.
Price, 1") cents.
24. The Manufacture and Preservation of I'nfermented ({rape Must. 1902.
Price, 10 cents.
25. Miscellaneous Papers: I. The Seeds of Rescue < irass and ( Miess. II. Saragolla
Wheat. HI. Plant Introduction Notes from South Africa. IV. Congres-
sional Seed and Plant Distribution Circulars, 1902-190:5. 190:5. Price, 15
cents.
26. Spanish Almonds and Their Introduction into America. 1902. Price, 15
cents.
27. Letters on Agriculture in the West Indies, Spain, and the Orient. 1902.
Price, 15 fenls.
28. The Mango in Porto Rico. 190:5. Price, 15 cents.
29. The Kffect of Hlack Hot on Turnips: A Series of Photomicrographs, Accom-
panied by an Explanatory Text. 1903. Price, 15 cents.
:;o. Pudding the Pecan. 1902. Price, 10 cents.
31. Cultivated Forage Crops of the Northwestern States. 1902. Price, 10 cents.
32. A Disease of the White Asli Caused by Polyporus Fraxinophilus. 1903.
Price, 10 cents.
33. North American Species of Leptochloa. 1903. Price, 15 cents.
34. Silkworm Food Plants: Cultivation and Propagation. 1903. Price, 15
cents.
35. Recent Foreign Explorations, as Bearing on the Agricultural Development
of the Southern States. 1903. Price, 15 cents.
3(>. The "Hluing" and the "Red Hot" of the Western Yellow Pine, with Spe-
cial Reference to the Black Hills Forest Reserve. 1903. Price, 30 cents.
37. Formation of the Spores in the Sporangia of Rhizopus Nigricans and of Phy-
comyces Nitens. 1903. Price, 15 cents.
38. Forage Conditions and Problems in Eastern Washington, Eastern Oregon,
Northeastern California, and Northwestern Nevada. 1903. Price, 15
cents.
39. The Propagation of the Easter Lily from Seed. 1903. Price, 10 cents.
40. Cold Storage, with Special Reference to the Pear and Peach. 1903. Price,
15 cents.
41. The Commercial Grading of Corn. 1903. Price, 10 cents.
42. Three Xew Plant Introductions from Japan. Price, 10 cents.
!.">. Japanese Ham boos and Their Introduction into America. 1903. Price, 10
cents.
44. The Hitter Rot of Apples. 1903. Price, 15 cents.
45. The Physiological Role of Mineral Nutrients in Plants. I 'rice, 5 cents.
4i. The Propagation of Tropical Fruit Trees and Other Plants. Price, 10 cents.
47. The Description of Wheat Varieties. 1903. Price, 10 cents.
4S. The Apple in Cold Storage. 1903. Price, 15 cents.
49. The Culture of the Central American Rubber Tree. 1903. Price, 25 cents.
50. Wild Rice: Its l*ses and Propagation. 1903. Price, 10 cents.
51. Miscellaneous Papers: Parti. The Wilt Disease of Tobacco and its Control.
1903. Price, 5 cents. Part II. The Work of the Community Demonstra-
tion Farm at Terrell, Texas. 1904. Price, 5 cents.
52. Wither-Tip and Other Diseases of Citrous Trees and Fruits Caused by Colle-
totrichum (.Jlu-osporioides. 1904. Price, 15 cents.
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