UNIVERSITY OF CALIFORNIA PUBLICATIONS
IN
AGRICULTURAL SCIENCE
Vol. 3, No. 12, pp. 369-498, 33 text-figs., pis. 43-74 June 30, 1919
ARE SOILS MAPPED UNDER A GIVEN TYPE
NAME BY THE BUREAU OF SOILS METHOD
CLOSELY SIMILAR TO ONE ANOTHER?
BY
ROBERT LAKIMORE PENDLETON
CONTENTS
PAGE
Foreword 369
Introduction 370
Need of a classification of soils 371
Historical development of the classification of soils 371
Plan of the present study 376
Discussion of results '. 377
Mechanical analysis 380
Chemical data 395
Bacteriological data 414
Greenhouse data 432
General discussion 467
Summary 481
Appendices 483
A. Methods and technique 483
B. Soil sample locations 490
FOREWORD
It is due the author, as well as to the undersigned, that a few
words be said by way of preparing the reader for what follows in this
paper. It will be observed, first, that the manuscript was, for an
unusually long time, in the printer's hands. Those who appreciate,
as few do today, the great rapidity with which the theories and the
methods in soil and plant study change, will readily catch the signifi-
cance of the foregoing sentence. Much of the work done by Mr.
Pendleton and some of the methods used may now properly be con-
sidered obsolete, or, conservatively speaking, at least obsolescent.
Nevertheless, I deem it of some importance to give the results obtained
in more or less detail, because of their historical value, and because Mr.
370 University of California Publications in Agricultural Sciences [Vol. 3
Pendleton's residence in India since the paper was written by him
has rendered satisfactory changes and deletions practically impossible.
Under these circumstances, with the burden of preparing the paper
for the press and the reading of the proof falling to me, the author
cannot well be held responsible for the inaccuracies and the infelicities
of expression which have been carried over from the original manu-
script without change. Moreover, the investigation was carried out
under my direction, and the plan of attack on the problem, together
with the methods employed, were suggested by me. Much that, in the
light of present knowledge, is superfluous or patently inexact or
erroneous in the paper is due to points of view held by me in 1915,
but now happily discarded. For all these, I assume the entire
responsibility, and absolve Mr. Pendleton in that regard.
On the other hand, the work having been carried out at my sugges-
tion and under my direction, I feel constrained, in justice to myself,
to say that the views expressed in this paper, and the conclusions
drawn are wholly Mr. Pendleton's and are not in agreement with those
held by me. I fail to see the cogency of the arguments set forth for
soil classification and mapping at this juncture in soil studies, and
cannot admit the pertinence of the analogy between classification of
other objects and of soils which the author of this paper employs.
My own general conclusion from the results obtained by Mr. Pendle-
ton is that they cast grave doubt on the validity of the Bureau of Soils
method of soil classification and mapping, and, incidentally on all
methods devised for that purpose to date. I cannot see how such
methods can serve us in scientific work at all, and, from the practical
standpoint, it would surely seem that guides for the purchaser of land
could be arranged more cheaply and less elaborately than by the soil
mapping methods extant. This statement has particular reference to
the subdivision of types very minutely, such as, for example, sandy
silty clay, clay loam adobe, etc. Such minute classification and sub-
division in view of the present state of our knowledge of soils, is
analogous, in my opinion, to carrying figures out to four decimal
places when it is known that the accuracy of the method makes it
impossible for them to be correct beyond the first decimal place. In
support of this seemingly radical conclusion, the reader will find much
of interest in the recent studies of this laboratory on variability in
soils, which have already appeared in this same series.
Chas. B. Lipman.
INTRODUCTION
For several years the University of California has been cooperating
with the United States Bureau of Soils in the mapping of the soils of
the agricultural portions of the State of California. The system of
mapping used is that developed by the Bureau of Soils. During the
year 1914-1915 the writer, representing the University of California,
was engaged in some of this soil survey work. In that year, in the
field, many questions arose regarding the criteria used, the methods.
1919] Pendleton: A Study of Soil Types 371
and the results of the scheme of mapping. It was thought that pos-
sibly some of the many questions could be answered through a labora-
tory study of some typical soils. This paper is a description of cer-
tain parts of the Avork done in this connection.
THE NEED OP A CLASSIFICATION OF SOILS
Since soils consist of a number of more or less distinct groups they
are fitting subjects for classification. In fact, it is my belief that it
is as necessary to have a classification for soils as for any other group
of natural objects in order that "the various and complex relations
may be shown as far as practicable," 1 and that there be a definite
basis for systematic and thorough investigations. 2 The advantages of
a classification of soils are apparent. But because soils grade gradu-
ally into one another, rather than exist as discrete individuals which
can be more easily considered and treated from a systematic stand-
point, the problem of evolving a satisfactory classification has been
particularly difficult. The many and diverse classifications proposed,
and the difficulty of applying many of these classifications under con-
ditions other than those for which they were evolved, testify to the
difficulty of the task in question.
The mapping of soils without a classification is impossible, and
so a brief summary of the development of soil mapping will bear a
close relation to the development of soil classification.
HISTORICAL DEVELOPMENT OF THE CLASSIFICATION
OF SOILS
The early history of the making of soil maps is that of geologic
maps as well, when soils, from the agricultural standpoint, and the
less distinct geological formations as such, were not sharply distin-
guished. Blanck 3 has an excellent treatment of the development of
soil mapping and of the modern continental European conceptions of
the nature and significance of soil maps. According to Blanck the
earliest record of a proposal to make a map to show something of the
nature of the actual material composing the surface of the earth is
that of Lister's proposal, in 1683, to the Royal Society of London.
i Coffey, G. N., Proc. Amer. Soc. Agron., vol. 1 (1909), p. 175.
2 Cameron, F. K., Eighth Internat. Cong. Chem., vol. 26 (1912), sees, via-xib;
app. pp. 699-706.
sFuhling, Landw. Ztg., vol. 60 (1911), pp. 121-45.
372 University of Calif ornia Publications in Agricultural Sciences [Vol. 3
But it was not until 1743 that Packe executed a map of Kent, showing
the occurrence of minerals by symbols. Apparently the next advance
was by the Germans, when Fuchsel, 1773, and Gloser, 1775, first used
colors to show granite, limestone, etc. This work constituted the first
real geologic map in the modern sense. There was not much activity
in this line of geologic work until 1870 or later. Such activity as there
was showed a lack of emphasis on soils in the agricultural sense of
the term.
The work on the geologic drifts of northern Europe, and studies of
the more recent lowland formations and soils of Germany led to soil
mapping. The first real soil map, according to Blanck, was prepared
by Benningsten-Forder of Halle, in 1864-67 ; while Carnot 4 states
that in 1863 M. Scipion Gras used superposable maps of the Depart-
ment of Isere, showing (1) geology, (2) agricultural soils, (3) alti-
tudes of agricultural regions, and (4) culture. The first true geologic-
agronomic map published by the Preussischegeologische Landesan-
stalt appeared in 1878.
The school of soil classification and mapping just mentioned, using
the geologic maps and methods as a point of departure have evolved
numerous though similar systems of recording the agrogeologic data
on the map. The geologic formation is shown by the color, and the
soil textures by sjmibols, while one or more of the following groups
of data appear and may be shown : topography by contours, subter-
ranean water by blue figures, location of borings in red with figures
referring to tables, amount of plant food elements or substances by
figures or hatchings, varying directions, color, or nature of lines, etc.
The nature and amount of the data shown and the manner of repre-
senting them vary a great deal. Some soilists, to use a term proposed
by Coffey, 5 advocate and use superposable maps to show one or more
groups of data, thus avoiding unnecessary confusion on the main map.
Hazard proposed a scheme of classification which is quite as
directly connected with the economic factors controlling the crops
grown, and with the assessable valuation of the land, as with the
actual or potential fertility of the soil itself. There are several classi-
fications of this type, involving the assessable values of the land.
i Rapport BUT Les cartes agronomiques, Bull. Min. Agr. France, 1893, no. 8,
pp. 956 73.
• r > Jour. Amor. Soc. Agron., vol. 8 (1916), p. 239.
eLandw. Jahrb., vol. 29 (1900), pp. 805-911.
Gregoire, A., and Halet, F., Bull. Inst. Chem. et Bact. Gembloux, 1906, no. 75,
pp. 1-43.
1919] Pendleton : A Study of Soil Types 373
This development of the mapping of soils as an outgrowth of areal
geology in France and Germany may be contrasted with the develop-
ment of soil classification from other viewpoints, such as that of the
Russian school. In Russia there is not the predominance of residual
and shallow soils which characterize much of western Europe and
which in France especially have led to the adoption of the geologic
basis of classification. Dokoutchayev and Sibirtzev have been the
chief proponents of a classification of soils based upon the ' ' conception
of a soil as a natural body having a definite genesis and a distinct
nature of its own. ' ' r
The genetic conditions of the formation of natural soils include
the following variable factors which cause variation :
(1) The petrographic type of the parent rock; (2) the nature and intensity of
the processes of disintegration, in connection with the local climatic and topo-
graphic conditions; (3) the quantity and quality of that complexity of organisms
which participate in the formation of the soil and incorporate their remains in it ;
(-4) the nature of the changes to which these remains are subjected in the soil,
under the local climatic conditions and physico-chemical properties of the soil
medium; (5) the mechanical displacement of the particles of the soil, provided
this displacement does not destroy the fundamental properties of the soil, its geo-
biological character, and does not remove the soil from the parent rock; and (6)
the duration of the processes of soil formation.
Upon this genetic basis there has been developed a series of soil zones,
ranging from the laterite soils in the tropics to the tundras in the
Arctic regions. The outstanding and controlling factor in the scheme
proposed is the relation of these zones to climate. For this reason the
statement usually seen is that climate is the basis of the classification. 8
There are nearly as many groups of intra-zonal and azonal soils as
of those belonging to the zones proper. The former include alkali,
marshy, alluvial, and other soils.
Hilgard, while actively interested in the' genetic viewpoint of soil
classification, was the foremost proponent of a classification upon
the basis of the natural vegetation growing upon the soil. 9 This
criterion is not always available, though some groups of plants, as the
alkali tolerant ones, are almost invariably present where the condi-
<Exp. Sta. Record, vol. 12 (1900), p. 704.
See also Sibirtzev, Cong. Geol. Intern., 1897, pp. 73-125; abstract in Exp. Sta.
Eec. vol. 12 (1900-01), pp. 704-12, 807-18.
Tulai'koff, X., The Genetic Classification of Soils, Jour. Agr. Sci., vol. 3 (1908),
pp. 80-85.
s Coffey, U. S. Bur. Soils, Bull. 85 (1912), p. 32; Jour. Amer. Soc. Agron.,
vol. 8 (1916), p. 241.
9 Hilgard, E. W., Soils (New York, Macmillan, 1906), pp. 487-549.
374 University of California Publications in Agricultural Sciences [Vol. 3
tions are unfavorable for the less resistant plants. Later Hilgard
and Loughridge 10 claimed that it is impracticable to attempt "a sat-
isfactory tabular classification in which each soil shall at once find its
pigeonhole prepared for it . . . because the subject matter is as yet
so imperfectly known. ' ' However, this does not dispute the justifica-
tion for making classifications for specific purposes or of specific
regions. With respect to this point there seems to be confusion. The
question is not whether soils can be classified at all or not, for every
observant farmer classifies the soil with which he is familiar, but
whether a satisfactory classification is possible over a large territory,
where soils are subject to the varying action of the important soil
forming agencies.
Still another type of soil mapping is that of Hall and Russell,
which is given in their admirable Report on the Agriculture and Soils
of Kent, Surrey, and Sussex." 11 In this district the soils are largely
residual, and form quite distinct groups, depending upon the parent
geologic formation. These groups of soils, such as the Clay-with-
flints and the Thanet beds, have very definite agricultural properties ;
hence the treatment of all phases of agriculture upon each separate
group of soils. Hall and Russell 12 present an excellent discussion of
the methods of soil classification and the interpretation of the soil
analyses used in their study. Russell 13 gives a very similar though
briefer treatment.
There are other more or less specialized classifications that have
been applied to local conditions and problems. As an example may
be cited Dicenty's work on grape soils. 14
Various modifications of the above schemes of classifying and map-
ping soils are found in general texts on soils. 15 Nowacki 16 proposes a
curious system, Genera et Species Terrarum. It is in Latin terminology.
The genera are based on the quality of the soil, whether stony, sandy,
clayey, peaty, etc., and the species are dependent upon the quantities
of organic matter and clay.
10 The Classification of Soils, Second Intern. Agrogeol. Conf., Stockholm, 1910,
p. 281.
ii London, Bd. Agr. and Fish., 1911.
12 Jour. Agr. Science, vol. 4 (1911), pp. 182-223.
is Soil Conditions and Plant Growth (London, Longmans, 1913), pp. 132-48.
14 Die ampelogeologische Kartierung. First Intern. Agrogeol. Cong., Budapest,
1909, pp. 257-71.
'■"• Ramann, E., Bodenkunde, Berlin, Springer, 1911.
Mitscherlich, E. A., Bodenkunde, Berlin, Parez, 1905.
i« Praktwche Bodenkunde (Berlin, 1892), pp. 130-80.
1919] Pendleton: A Study of Soil Types 375
Soil Surveying in the United States. — In a brief way, it has been
shown how there arose the different systems of soil classification.
Only a few typical systems of classifications, and something of the
reasons for the divergences, have been mentioned. 17 Probably the one
agency that has carried on the most extensive soil classification and
mapping is the Bureau of Soils of the United States Department of
Agriculture. It is now proposed to discuss and in a measure criticize
the work of the Bureau of Soils, the one organization that has, more
than any other, succeeded in applying a detailed system of soil classi-
fication over extensive areas.
The problems that the Bureau had to face during its early exist-
ence were special studies of the soils of certain crops, especially of the
tobacco districts. 18 Later the soil utilization work of the Bureau of
Soils was transferred to other branches of the Department of Agri-
culture, leaving as the main task for the Bureau the systematic classi-
fication and mapping of the soils of the United States.
Coffey 19 has so well discussed the present day conceptions of the
bases for the classification of soils, that it does not seem necessary to
repeat any portion of that excellent statement here. He showed that
the Bureau of Soils, in its method of classifying soils, uses a combina-
tion of a number of systems. This matter is dealt with more in detail
in an article b} r Coffey, 20 and the Report of the Committee on Soil
Classification of the American Society of Agronomy. 21 The question
often arises as to the validity of making the close distinctions regard-
ing color, texture, geologic origin, etc., and is one which should be
dealt with in order to render less empirical the nature of most of the
criteria which are used at present. See the Report of the Committee
on Soil Classification and Mapping. 22
Because of different views regarding soils and soil fertility from
those held by the Bureau of Soils, the Illinois Agricultural Experi-
ment Station has undertaken a soil survey and classification, under the
direction of Dr. C. G. Hopkins, which is independent of the Bureau
17 See Coffey's excellent treatment of the soil survey work in this country.
The Development of Soil Survey Work in the United States with a Brief Reference
to Foreign Countries, Proc. Amer. Soc. Agron., vol. 3 (1911), pp. 115-29.
is Whitney, Extension and Practical Application of Soil Surveys, Off. Exp.
Sta., Bull. 142 (1903), pp. 111-12; The Purpose of a Soil Survey, U. S. Dept.
Agr., Yearbook, 1901, pp. 117-32.
is A Study of the Soils of the United States, U. S. Bur. Soils, Bull. 85 (1912),
pp. 24-38.
20 Jour. Amer. Soc. Agron., vol. 8 (1916), pp. 239-43.
2i Ibid., vol. 6 (1914), pp. 284-88.
22 Ibid., vol. 8 (1916), pp. 387-90.
376 University of California Publications in Agricultural Sciences [Vol. 3
of Soils, and differs from its methods in a number of ways. Since the
soils of Illinois are of a much narrower range of variation than are
those of the whole of the United States, the system of classification
for the state need not be so elaborate. The soils are divided accord-
ingly as they have been glaciated or not, and if glaciated, in what glaci-
ation period. They are further divided according to color, topogra-
phy, and texture of soil and subsoil. 23 Correlation of the types of
soil mapped in the various areas, one of the greatest sources of criti-
cism of the Bureau of Soils survey methods, is more easily handled
in the Illinois work, since it is possible for the one in charge of the
work to pass personally, while in the field, upon all correlation and
the establishment of all new types. It is insisted that the field men
map accurately and in sufficient detail. This insures the accuracy of
the maps as regards the standards adopted, the information is specific,
and the local users of the maps are not misled. 24 In connection with
the field classification and mapping, pot and plot cultures are carried
on, not so much to test the relative fertility of the untreated soils, but
to determine the effects of the application of various sorts and quanti-
ties of fertilizers. Hopkins, 25 to show the differences in detail between
the U. S. Bureau of Soils mapping and that of the Illinois Experi-
ment Station, compares a U. S. Bureau survey of 1902 with a state
survey published in 1911. This is not entirely fair, because with the
increase of field knowledge of soils gained by them and the realiza-
tion of the need of representing the soils in more detail, a survey
made by the Bureau in 1911 would almost certainly show much more
detail and show it with greater accuracy than the maps made in the
early period of the work. This point may be strengthened by the
notes given below on the comparison of a portion of an early survey
made in southern California by the Bureau of Soils with a recent
survey of the same soils made by the Bureau and the University of
California working in cooperation.
PLAN OF THE PRESENT STUDY
The present study is an attempt to see if certain soil types mapped
as the same from different areas in the state of California, and judged
to be the same by the criteria used by the Bureau of Soils, are the
28 Hopkins, Soil Fertility and Permanent Agriculture (Boston, Ginn, 1910)
pp. 54-57.
24 Ibid., ]>. 115.
28 Jbid., pp. 114-15.
1919] Pendleton: A Study of Soil Types 377
same or similar when examined from the laboratory standpoint. For
example, we may take the Hanford fine sandy loam, which is one of
the types that has been used in the present study. According to the
criteria of color, mode of formation, origin (as judged by the presence
of mica), nature of subsoil, texture, etc., this soil has been found and
mapped in a number of areas that have been mapped in this state.
But will these various bodies of soil, from widely separated portions
of the state, when judged by laboratory and greenhouse studies on
samples as nearly representative as possible, appear to be the same or
similar ?
The types selected for such a study as this should fulfil the follow-
ing conditions : first, they should have at least a reasonably wide dis-
tribution in the state so as to have been mapped in a number of differ-
ent soil survey areas ; and second, the several types should be repre-
sentative of different classes of soils (clays, loams, sandy loams, etc.),
so that contrasts could be obtained between the types.
In the collection of samples it was aimed to obtain representative
samples from each of a number of bodies of soil of the types selected ;
not to obtain possible variations from the ideal in any one body. In
the laboratory the soils were compared with regard to their physical
composition in the surface horizon, to their chemical composition in
three horizons, and to their relative bacteriological activities. In the
greenhouse the soils (surface horizon only) were placed in large pots
and their comparative ability to produce various crops was studied.
No claim is made that these criteria should be the ones used in
determining the systematic classification of soils or in determining
the relative fertility of the soils. They were merely used to determine
how nearly the soils classed under a given type name agree from the
standpoints named.
DISCUSSION OF RESULTS
The bacteriological and chemical determinations were run in dupli-
cate so that the figures presented are averages. It is considered that
this gives fairer figures for comparison, especially since the determina-
tions were run on separate samples, and not on aliquots of a single
solution from a single sample.
There is a very important factor which should always be kept in
mind especially when considering the bacteriological and greenhouse
comparisons. This is the factor of the probable error. Though the
378 University of California "Publications in Agricultural Sciences [Vol. 3
advisability of judging all results in the light of the probable error
is admitted, no attempt has been made to apply this factor to the
results reported in this paper. As the result of the effect which such
a factor might have upon the results of bacteriological determina-
tions carried on only in duplicate, or upon the results of greenhouse
work done in triplicate, one hesitates to draw conclusions, especially
those based upon minor variations. Hence in this work only the more
marked results will be considered of significance.
When planning the work it was thought that three or four samples
of a type would be enough to show whether or not a given type was
approximately uniform, or widely variable, and as to whether the
types were similar to one another, or quite dissimilar. But it now
seems, after comparing the determinations run on the larger number
of samples of the Hanford and San Joaquin types, 9 and 8 respec-
tively, with the determinations run on the Altamont and Diablo types,
of which there were a much smaller number of samples, 3 and 4
respectively, that the larger series gives a much better insight into the
variations of a given type and affords a much better basis for con-
clusions.
Hence, as regards the laboratory work thus far carried out, the
emphasis has been placed upon the Hanford fine sandy loam and the
San Joaquin sandy loam. Determinations have not been completed
on the Altamont and Diablo series to the extent that they have on the
former two.
It is of no little significance that the Hanford fine sandy loam and
the San Joaquin sandy loam are very widely contrasted soils agricul-
turally. The Hanford is typical of good recent alluvial soil in this
state ; while the San Joaquin is typical of wide expanses of ' ' old valley
filling" soils that are considered poor as regards crop producing
power and are underlain by compact iron-cemented hardpan. Conse-
quently, the results of comparing soils so different from an agricul-
tural point of view, and so radically different as regards soil survey
criteria (though the textures are quite similar) will be of considerable
interest. They are of greater interest than the comparisons between
the Diablo and Altamont soils, as the latter are quite similar in agri-
cultural value and use, as well as in field appearances. Between the
Diablo or Altamont and the Hanford or San Joaquin one cannot
judge as closely regarding variations, for the soils are so radically
different. On the other hand, one can compare the soils of the heavy
and light types to see to what extent the chemical and bacteriological
results differ as compared with the physical results.
02.5 0.5 /. Z. 4 9. 16. 32. 64. Grits.
Size of Particles nam -
Fig. 1. Graph showing the results of the Hilgard elutriator method of
mechanical analysis on the four samples of Diablo clay adobe.
380
University of California Publications in Agricultural Sciences [Vol. 3
Mechanical Analysis
Hilgarcl Elutriator Method. — That there is a wide variation be-
tween the samples is apparent (figs. 1-4). In fact, there is about
as wide a range of differences among the samples of the Hanford
%
45
40
35
30
20
i:.
10
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N,
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32
64 m m.
Pig. 2. Graph showing the results of the Hilgard elutriator method of
mechanical analysis on the three samples of Altamont clay loam.
fine sandy loam and among those of the San Joaquin sandy loam as
between the two types. The most outstanding differences are where
they ought to be, to show the differences that the type names presup-
pose, i.e., in the "coarse sand" (64 mm.) and the "grits." The sam-
ples of the San Joaquin sandy loam average a larger proportion of
each of these separates than do the Hanford fine sandy loam soils.
1919]
Pendleton : A Study of Soil Types
381
In the Hanford, no. 14 is notably heavier than the others, as shown
by its silt content, which is nearly half again as great as that of the
next highest sample.
The gravel content (sizes above 2 mm.) is interesting in its uni-
formity. In the San Joaquin soils the two samples above 1% are
:lqy Q25 0.5 I 2. 4- 8 16 32 64- Grits
Size of Particles. mm
Fig. 3. Graph showing the results of the Hilgard elutriator method of
mechanical analysis on the eight samples of San Joaquin sandy loam.
nos. 11 and 26. The material in the latter soil is composed almost
wholly of iron concretions, leaving sample no. 11 as the only soil with
more than 1% actual gravel. In the Hanford samples none were
found to have more than 1.5% gravel.
The Hilgard method does not include any precise subdivision of
the soils into groups or classes according to texture. Dr. Hilgard was
not in favor of making the fine distinctions in texture that other
382
University of California Publications in Agricultural Sciences [Vol. 3
investigators have emphasized. But if there were such a scheme,
similar to that which the Bureau of Soils uses, 26 it would be an easy
matter to compare the results obtained through the use of the elutri-
ator, and determine whether or not the soils examined belong to a
given class. The simple comparison of the quantities, in different
40%
0^5~ 0.5 1.0 2.0 4.0 8.0 16. 32. 64-. Grits.
Size of Particles. mm.
Fig. 4. Graph showing the results of the Hilgard elutriator method of
mechanical analysis on the nine samples of Ilanford fine sandy loam.
samples, of any given separate or separates is not absolute. For it
must be realized that the conception of a soil class includes a certain
range in the quantities of particles of the various sizes. This must
be so since soils are ordinarily grouped into but ten or twelve class
textures, while there exist among soils those with all gradations in
the quantities of particles of the various sizes.
28 Instructions to Field Parties, U. S. Bur. Soils, Bull. 1914, p. 75; ibid.,
Bull. 85 (11)12;, p. 28.
1919]
Pendleton: A Study of Soil Types
383
And because the ranges in the sizes of the soil particles separated
by the Bureau of Soils method cut across those of the Hilgard
method, it is impossible to regroup the results so that the Bureau of
Soils grouping into textures may be applied. But without any such
scheme, desirable as it may be, it has been pointed out that there is
clearly apparent a rather wide variation in the analyses of the several
samples of a type. All the soils representative of a given type are by
no means closely similar to one another.
Table 1 — Comparison of Textures
Texture determined by
Texture as judged in the field
mechanical analysis
*1
Diablo clay adobe
Clay
2
Diablo clay adobe
Clay
3
Altamont clay loam
*Silty clay
4
Altamont clay loam
Clay loam (sandy)
5
Diablo clay adobe
Clay
6
Diablo clay adobe
Clay
7
Altamont clay loam
Clay loam (heavy)
10
San Joaquin sandy loam
*Fine sandy loam
11
San Joaquin sandy loam
Sandy loam (heavy)
12
San Joaquin sandy loam
*Fine sandy loam
13
San Joaquin sandy loam
*Fine sandy loam (heavy)
14
Hanford fine sandy loam
Fine sandy loam (loam)
15
Hanf ord fine sandy loam
Fine sandy loam
16
Hanford fine sandy loam
* Sandy loam
17
San Joaquin sandy loam
Sandy loam
18
San Joaquin sandy loam
Sandy loam
19
Hanford fine sandy loam
* Sandy loam (heavy)
20
Hanford fine sandy loam
Fine sandy loam
21
Hanford fine sandy loam
Sandy loam
22
Hanford fine sandy loam
Fine sandy loam
23
Hanford fine sandy loam
Fine sandy loam
24
Hanford fine sandy loam
Fine sandy loam
25
Hanford fine sandy loam
Fine sandy loam
26
San Joaquin sandy loam
Sandy loam
Note. — Textures not judged correctly in the field.
Mechanical Analysis by the Bureau of Soils Method. — Among the
other determinations made by the Division of Soil Technology on the
surface horizons of the twenty-four soils used in this investigation
was that of making the mechanical analysis. The tables show the
percentages of the several separates. In all cases the figures represent
averages of duplicate determinations and in some cases the averages
of quadruplicate determinations. With this method, as well as with
the Hilgard elutriator, there are shown wide variations between the
384 University of California Publications in Agricultural Sciences [Vol. 3
.005 .005 .05 JO .25 .5 1.0
mm. -.05 -JO -£5 -.5 -/.Q -2.0
miD. mm. mm. mm. mm. mm.
Pig. 5. Graph showing the results of the Bureau of Soils method of
mechanical analysis on the four samples of Diablo clay adobe.
1919]
Pendleton: A Study of Soil Types
38:
samples of a given type. But the graphs of the percentages (figs.
5-8), determined by the Bureau of Soils method for the several types
are not as closely similar as the graphs of the elutriator results for
the same types. That is, using the Bureau of Soils method, the graph
of the Hanford fine sandy loam does not resemble th,at of the San
Joaquin sandy loam as much as do the graphs of the results made
Fig. 6.
.005 .005-.05 .05-. 10 .10-. 25 .25-. 5 .5-1.0 1.-2.
Graph showing the results of the Bureau of Soils method of
mechanical analysis on the three samples of Altamont clay loam.
upon the same soils by the Hilgard elutriator method. This would
lead one to believe that the Bureau of Soils method of mechanical
analysis is the better suited for separating soils into groups; even
though these soils which were classified in the field according to the
differences which are the more prominent would be expected to show
greater differentiations when examined by the Bureau of Soils labora-
tory methods.
386
University of California Publications in Agricultural Sciences [Vol. 3
Comparison of Textures. — Table 1 gives the texture as shown on
the soil survey map of the locality, as well as the results of the labora-
tory check. This texture as given on the map was also judged by me
.005 .005 .05 .10 25
-.05 -./O -Z5 -.5
Size of Particles.
Pig. 7. Graph showing the results of the Bureau of Soils method of
mechanical analysis on the eight samples of San Joaquin sandy loam.
in the field to be more or less true to the type as mapped. I say more
or less true, for the field notes, as given in appendix B, show that in
several cases I was unable to obtain in the locality what I believed to
1919]
Pendleton: A Study of Soil Types
387
be a sample of the soil thoroughly typical of the class and type in
question. Sample no. 3 had a large lime content which I thought
might more or less obscure the texture. ''Slightly heavy, and barely
enough sand for a sandy loam" is the comment on sample 12, while
"a heavy sandy loam, approaching a loam" is found in the notes on
sample 13. The second column of the table shows the class sub-
divisions into which the soils were placed according to the mechanical
analysis. The words in parenthesis show modifying conditions but
do not indicate a change in the class. In considering the class groups
such as sandy loam, fine sandy loam, etc., it should be remembered
that though the groups are rather broad, the limits are arbitrary
and quite sharp. So the results of a mechanical analysis may place
a soil in the sandy loam class if 25% or more is fine gravel, coarse and
medium sand, while if less than 25% be present the soil belongs to the
fine sandy loam class, providing at the same time the amounts of silt,
clay, and fine sand are within the specified limits. The two soils may
be a great deal alike in texture though placed in different classes.
The failure of my judgment regarding the texture shows one of the
difficulties that the field man is continually facing. And his failure
to judge textures correctly is one of the causes of criticism of soil
survey work.
Table 2 — Mechanical Analyses,
HlLGARD ELUTRIATOR METHOD
Diablo Clay Adobe
Separates
Samples
r
Diameter,
mm.
Velocity,
mm. per
second
Name
1-A
%
2-A
%
5-A
%
6-A
%
Clay
.01
0.25
44.16
35.81
44.97
64.63
Fine silt
.01 -.016
0.25
23.91
34.08
25.57
25.13
Medium silt
.016-.025
0.5
5.97
7.37
4.14
1.03
.025-.036
1
8.10
9.09
5.28
1.83
Coarse silt
.036-.047
2
7.77
7.47
5.45
1.99
.047-.072
4
6.05
4.09
6.18
2.13
Fine sand
.072-.12
8
3.28
1.33
5.81
2.07
.12 -.16
16
0.48
0.43
1.73
0.90
Medium sand
.16 -.30
32
0.08
0.21
0.38
0.21
Coarse sand
.30 -.50
64
0.18
0.11
0.49
0.11
Total weight
of separates, gm.
19.18
19.62
19.30
19.68
Weight of original sample, gm.
18.83
18.88
18.66
18.16
Grits, %
0.5-2.0 mm.
0.26
0.29
0.57
0.10
Hygroscopic
moisture, %
6.20
5.93
7.18
10.12
University of California Publications in Agricultural Sciences [Vol. 3
.005 .005 .05 JU .25 .5 1.0 mm
-.05 , -.1.0 -Z5 -.5 -1.0 2.0 mm.
Size of Particles
Pig. 8. Graph showing the results of the Bureau of Soils method of
mechanical analysis on the nine samples of llnnford fine sandy loam.
1919]
Pendleton: A Study of Soil Types
389
Table 3 — Mechanical Analyses, Hilgard Elutriator Method
Allamont Clay Loam
Separates
'
Diameter
mm.
Velocity
mm. per
second
A
Name
3 -A
%
4-A
%
7-A
%
Clay
.01
0.25
28.48
26.41
22.65
Fine silt
.01 -.016
0.25
43.42
17.73
41.18
Medium silt
.016-.025
0.5
2.96
2.39
4.67
.025-.036
1
4.37
4.82
8.51
Coarse silt
.036-.047
2
4.95
4.89
6.01
.047-.072
4
5.52
7.52
7.90
Fine sand
.072-.12
8
5.14
8.83
5.54
.12 -.16
16
3.89
13.61
1.98
Medium sand
.16 -.30
32
0.88
10.40
0.95
Coarse sand
.30 -.50
64
0.21
3.39
0.61
Total weights
of separates,
gm.
18.71
19.54
20.96
Weight of ori
ginal sample,
gm.
18.50
19.16
19.21
Grits, %
.5-2.0 mm.
3.98
8.09
1.63
Hygroscopic moisture, %
8.08
4.37
4.09
Table 4 — Mechanical Analyses, Hilgard Elutriator Method
San Joaquin Sandy Loam
Separates
Sampl
es
Diameter
t mm.
Velocity,
mm.
per
second
Name
10-A
%
ll-A
%
12-A
%
13-A
%
17-A
%
18-A
%
21-A
%
2 6- A
%
Clay
.01
0.25
11.14
15.46
8.99
10.75
10.53
8.72
8.35
16.64
Fine silt
.01 -.016
0.25
20.24
31.88
26.57
24.04
16.20
18.56
14.73
20.78
Medium
silt
.016-.025
0.5
1.44
2.73
2'.31
4.64
1.81
3.06
3.54
3.83
.025-.036
1
6.54
9.11
1.33
9.86
5.89
6.93
6.98
9.24
Coarse silt
.036-.047
2
8.36
10.23
1.19
9.59
5.82
6.90
7.10
7.09
.047-.072
4
9.50
8.41
10.14
10.05
8.46
8.45
7.67
8.89
Fine sand
.072-.12
8
10.66
7.47
10.72'
10.92
12.04
9.72
12.86
5.77
.12 -.16
16
10.30
5.97
10.88
16.14
13.43
10.56
13.53
3.85
Medium
sand
.16 -.30
32
14.69
6.91
11.75
1.96
19.21
16.59
3 3.05
0.86
Coarse san
d .30 -.50
64
7.11
1.32
3.54
2.12
6.60
10.50
12.14
23.04
Total weight of separates, gm.
20.02'
20.44
19.99
20.10
20.38
20.06
20.33
20.14
Weight of
original sample, gm.
19.80
19.51
19.72
19.76
19.85
19.86
19.85
19.69
Grits, %
0.5-2.0 mm.
16.70
23.54
8.84
8.10
23.12
32.00
28.50
36.00
Hygroscop
>ic moisture
, %
0.98
2.48
1.38
1.22
0.75
0.70
0.75
1.57
Note. — All weighings made on the water free basis.
390
University of California Publications in Agricultural Sciences [Vol. 3
Table 5 — Mechanical Analyses, Hilgard Elutriator Method
Han ford Fine Sandy Loam
Separates
Name
Clay
Fine silt
Medium
silt
Coarse silt
Fine sand
Medium sand
Coarse sand
Velocity,
mm.
Diameter per
mm. second
0.25
0.25
0.5
1
2
4
8
16
32
64
.01
.01 -.016
.016-.025
.025-.036
.036-.047
.047-.072
.072-12
.12 -.16
.16- .30
.30- .50
Total weight of separates, gm.
Weight of original sample, gm.
Grits, % 0.5-2.0
Hygroscopic moisture, %
14- A
%
12.89
37.25
4.19
8.63
7.95
6.23
5.26
7.15
8.81
1.43
20.19
19.46
4.12'
2.73
Samples
15-A
%
8.16
19.39
3.05
5.04
6.57
10.23
12.31
13.93
15.29
6.02'
20.23
19.90
13.23
0.49
16-A
%
11.97
24.61
3.22
5.06
5.99
7.27
8.57
9.76
16.05
7.51
20.53
19.69
25.47
1.54
19-A
%
11.09
5.95
1.67
5.27
7.14
12.76
17.79
12.00
24.20
2.13
20.08
19.82
7.85
0.89
20-A
%
10.55
22.09
6.40
8.40
7.68
9.93
10.48
12.29
10.03
2.70
20.27
19.73
6.71
1.34
22-A 23-A
7.97
14.15
3.15
5.29
6.47
11.30
17.15
17.39
14.87
2.27
20.06
19.81
3.07
0.94
8.68
22.57
5.90
6.89
10.53
13.03
12.71
7.94
9.88
1.85
20.30
19.78
7.24
1.10
2 4- A
%
6.47
11.11
1.20
5.08
7.48
13.91
19.27
21.56
12.36
1.50
20.26
19.83
6.85
0.84
25-A
%
6.65
14.54
1.59
6.36
7.91
12.64
18.11
9.55
19.15
3.50
19.18
19.78
3.83
1.10
Table 6 — Mechanical Analyses, Bureau of Soils Method
Diablo Clay Adobe
Separates
Sampb
3S
Name
Diameter
mm.
l-A
2-A
%
5-A
%
6-A
%
Clay
.005
44.81
44.44
45.67
56.01
Silt
.005- .05
32.00
42.51
23.01
14.28
Very fine sand
.05 - .10
19.61
11.35
21.58
25.58
Fine sand
.10 - .25
1.36
1.33
4.81
2.10
Medium sand
.25 - .5
0.26
0.69
0.95
2.05
Coarse sand
.5 -1.0
0.58
0.20
1.56
0.00
Fine gravel
1.0 -2.0
0.03
0.02
0.04
0.00
Note. — Determinations made by the Division of Soil Technology.
Table 7 — Mechanical Analyses, Bureau of Soils Method
Altamont Clay Loam
Separates
Samples
Name
Diameter
mm.
3-A
%
4-A
%
7-A
%
Clav
.005
33.19
26.50
31.84
Silt
.005- .05
31.76
17.35
37.40
Very fine sand
.05 - .10
22.81
39.15
24.70
Fine sand
.10 - .25
8.97
6.08
3.27
Medium sand
.25 - .5
1.99
7.78
0.92
Coarse sand
.5 -1.0 "
1.74
3.06
0.55
Fine gravel
1.0 -2.0
1.01
1.22
0.22
NOTE. — Determinations made by the Division of Soil Technology.
1919]
Pendleton: A Study of Soil Types
391
Table 8 — Mechanical Analyses, Bureau of
Soils Method
San Joaquin Sandy
Loam
Separal
es
Samples
A
Name
^
Diameter
mm.
10-A
%
ll-A
%
12-A
%
13-A
%
17-A
%
18-A
%
21-A
%
2 6- A
%
Clay
.005
10.78
15.77
16.16
16.94
11.77
10.49
8.28
17.38
Silt
.005- .05
21.60
35.97
25.04
22.70
15.97
2'6.74
17.70
18.17
Very fine sand
.05 - .10
28.07
18.53
27.42
47.01
20.42
12.02'
15.92
13.84
Fine sand
.10 - .25
19.96
2.66
17.07
3.99
22.57
16.61
21.27
10.26
Medium sand
.25 - .5
9.20
6.96
5.80
4.69
10.75
13.85
13.57
14.72
Coarse sand
.5 -1.0
9.08
8.51
6.52
2.96
13.81
16.52
21.41
24.26
Fine gravel
1.0 -2.0
1.34
12.52'
2.15
1.81
3.13
4.07
2.07
2.02
Note. — Determinations made by the Di
vision of
Soil Technology.
Table 9 — Mechanical Analyses, Bureau of Soils Method
Ranford Fine Sandy Loam
Separates
A
Samples
A
f *\
Diameter
Name mm.
14-A
%
15-A
%
16- A
%
19- A
%
20-A
%
22-A
%
23-A
%
2 4- A
%
25-A
%
Clay .005
14.10
12.08
16.84
15.28
15.95
7.79
10.61
9.83
7.60
Silt .005- .05
39.25
22.42
16.16
15.03
32.90
22.70
24.38
11.42
12.90
Very fine sand .05 - .10
22.66
37.12
16.46
32.87
22.58
36.15
38.73
42.05
67.37
Fine sand .10 - .25
17.54
6.51
17.32
8.13
18.20
27.78
16.51
28.73
5.88
Medium sand .25 - .5
4.71
11.40
11.70
15.42
4.97
4.21
4.66
4.27
3.47
Coarse sand .5 -1.0
1.99
8.49
15.54
9.27
3.07
1.47
3.28
3.01
1.27-
Fine gravel 1.0 -2.0
0.13
1.91
5.27
3.63
0.20
0.20
1.48
1.02
1.02
Note. — Determinations made
by the Division i
af Soil Technology.
Moisture Equivalent. — The moisture equivalents of the surface
horizon samples were determined by the Division of Soil Technology
(table 10, and figs. 9, 10). The different types gave quite distinct
averages, though there was considerable variation within the type.
The Diablo clay adobe varied from 37% to 57%, with an average of
47%. The Altamont clay loam varied from 22% to 37%, with 28%
as an average. The San Joaquin sandy loam varied from 7% to
15%, with the average of 11%. The Hanford fine sandy loam varied
from 11% to 25%, with 15% as the average. These figures show
that as a whole the moisture equivalents of the several types are
distinct, though there is the usual overlapping in some cases. The
samples of a given type are in many instances closely similar, though
not always or even usually so.
392 University of California Publications in Agricultural Sciences [Vol. 3
60
55
50
45
10
30
25
20
15
10
1
/
1
\
\
\
\
\
\
/
/
/
/
Moisture
Equivalent
Hygro.
Coef.
35
;;<>
20
10
\
\
\
\
\
\
\
\
\
\
\
\
^-
Moisture
Equivalent
Hygro.
Coef.
12 5 6 Soils 3 4 7 Soils
Fig. 9. Graph showing the results of the determination of the moisture
equivalent and of the hygroscopic coefficient on the four samples of Diablo
clay adobe and the three samples of Altamont clay loam.
1919]
Pendleton: A Study of Soil Types
393
Table 10 — Moisture Equivalent
Diablo Clay
A
Adobe
Altamont Clay Loam
San
No.
Joaquin
Loam
A
Sandy
Hanford Fine
Loam
A
Sandy
r
No.
%
Average
No.
%
Average
%
%
Average
%
No.
%
Average
1-A
49.70
3-A
38.10
10-A
10.30
14-A
25.80
48.90
49.30
37.80
37.95
10.10
10.20
25.20
25.50
2-A
37.40
4-A
23.41
11-A
15.52
15-A
11.50
36.80
37.10
22.35
22.88
15.54
15.53
11.20
11.35
5-A
46.55
■ 7-A
23.90
12-A
13,72
16-A
15.60
48.10
47.32
23.90
23.90
13.62
13.67
15.60
15.60
6-A
58.80
Average
28.94
13-A
14.50
19-A
13.30
56.80
57.80
14.60
14.55
14.30
13.80
Average
i 47.88
17-A
8.90
20- A
18.41
8.98
8.94
18.38
18.39
18-A
2 1-A
26-A
7.92
7.87
7.16
7.09
11.30
11.81
7.89
7.12
11.55
22-A
2 3-A
24-A
12.73
12.22
11.08
10.90
16.30
16.17
12.47
10.99
16.23
Average
! 11.18
25-A
11.17
12.72
11.94
Average
15.14
Note. — Determinations made by the Division of Soil Technology.
Table 11 — Hygroscopic Coefficient
Diablo Clay
A
Adobe
Altamont Clav
A
Loam
San Joaquin
Loam
A
Sandy
Hanford Fine
Loam
A
Sandy
No.
%
Average
%
No.
Average
% %
No.
%
Average
%
No.
%
Average
%
1-A
15.88
3-A
17.48
14-A
5.35
10-A
2.46
15.08
15.48
18.45
17.93
4.70
5.03
2.51
2.49
2-A
9.90
4-A
9,60
15-A
1.31
11-A
3.44
9.48
9.69
7.00
8.30
1.39
1.35
3.45
3.44
5-A
14.18
7-A
7.92
16-A
3.90
12-A
3.58
13.90
14.04
5.92
6.92
3.60
3.75
3.45
3.52
6-A
15.20
Average
11.05
19-A
1.66
13-A
2.50
15.70
15.45
1.80
1.73
2.60
2.55
Average
s 13.66
20- A
2.90
17-A
1.84
3.02
2.96
1.62
1.73
22-A
2.48
2.89
2.69
18-A
2.10
2.00
2.05
23-A
2.38
2.53
2.46
21-A
1.98
1.92
1.95
24-A
2.39
26-A
3.57
24-A
2.39
3.52
3.55
2.37
2.38
Average
2.66
25-A
1.78
1.84
1.81
Note. — Determinations made by the Division of Soil Technology.
394 University of California Publications in Agricultural Sciences [Vol. 3
15
10
Moisture
Equiv.
Hygro.
Coef.
10
11
12
13
18
21
2G Soils
20
ir>
10
X
\
^
\
-""
Moisture
Equiv.
10
20
22
23
24
Hygro.
Coef.
23 Soils
Fig. 10. Graph showing the results of the determination of the moisture
equivalent and of the hygroscopic coefficient on the eight samples of San
Joaquin sandy loam and the nine samples of Ilanford fine sandy loam.
Hygroscopic Coefficient. — The determination of this coefficient,
also by the Division of Soil Technology, shows no very distinct values
for the several types under consideration (table 11, figs. 9,10). The
Diablo clay adobe samples vary from 9.6% to 15.4%, with the average
of 13.69? • The Altamont clay loam samples vary from 6.9% to
17.9%, averaging 11%. The San Joaquin sandy loam varies from
1919]
Pendleton: A Study of Soil Types
39;
1.7% to 3.5%, with the average of 2.66%, while the Hanford fine
sandy loam varies from 1.3% to 5%, with the average of 2.68%.
There is no question that here the range of values within every type
is greater than that from type to type. Even excluding those sam-
ples shown by the mechanical analysis to be not true to name there
is a wide range within each type — a range too wide to allow one
to answer the question of this paper in the affirmative.
%
V.6
0.2
0.1
00
P 2 5
N
6 Soils
Fig. 11. Graph showing the percentages of nitrogen and of phosphorus in
the four samples of Diablo clay adobe.
The Chemical Data
Total Nitrogen
Diablo clay adobe. — There is more variation in nitrogen content
between the different representatives of the type than one would
expect from a visual examination of the soils (table 12 and fig. 11).
No. 2 would be expected to contain less nitrogen than no. 5 because of
the lighter color, but such is not the case. In the A horizon, no. 5
shows the lowest notal nitrogen content with 0.084%, no. 2 is higher
with 0.092%, no. 1 with 0.104%, and no. 6 is the highest with 0.117%.
The decrease in the nitrogen content with the increase in depth is
normal. In the C horizon, no. 1 has the lowest total nitrogen content
with 0.057%, and no. 6 the highest, with 0.078 %.
Altamont clay loam. — The agreement between the A samples is
fairly close (table 13, and fig. 12). No. 4 has 0.103%, no. 7, 0.104%,
and no. 3 has 0.123%. This gives an average for the surface soil of
0.110%, as compared with 0.099% in the Diablo clay adobe. It is to
be noted that the nitrogen content of the subsoil is relatively less
than that in the Diablo subsoils, 0.071% and 0.056% in the Altamont
B and C horizons, respectively, as against 0.076% and 0.065% in the
396
University of California Publications in Agricultural Sciences [Vol. 3
B and C horizons of the Diablo. The average amount of nitrogen is
higher in the A horizon of the Altamont than in the Diablo, contrary
to what one would expect from the color of the soils, since the Alta-
mont is typically a brown soil and the Diablo a dark gray to black soil.
San Joaquin sandy loam. — The nitrogen content of these soils is
uniformly low (table 14 and fig. 13), from 0.03% to 0.05%, and is but a
third to a half of what Hilgard believed adequate for crop production.
0.6
0.2
0.1
00
P 2 5
7 Soils
Fig. 12. Graph showing the percentages of nitrogen and of phosphorus in
the three samples of Altamont clay loam.
^ P 2 Q 5
0.0
26 Soils
Fig. 13. Graph showing the percentages of nitrogen and of phosphorus in
the eight samples of San Joaquin sandy loam.
The nitrogen content is seen to vary more or less directly with the
amount of the finer sediments present in the soil — nos. 11 and 12
being heavy members of the type, with 0.05% and 0.047% respec-
tively, and nos. 17 and 18 light members of the type with 0.029% and
0.027% respectively. It may be noted that the nitrogen content of
the various horizons are not as far apart as in the other types. The
averages for the three horizons are: A — 0.037%, B — 0.027%, and
C — 0.026%. It must be borne in mind that the San Joaquin sandy
Loam horizons are not full 12-inch samples, and that the total depth
of the sampling is less.
1919]
Pendleton: A Study of Soil Types
397
Han ford fine sandy loam. — Here again in the A horizon the nitro-
gen content is fairly uniform (table 15, and fig. 14), with from 0.045%
to 0.072%, if the extra typical no. 14, with 0.119%, be left out of
consideration. One would suppose these soils to be higher in their
or
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
x
/
\
— — -~
— -^.^
P205
16
19
20
22
23
24
25 Soils
Fig. 14. Graph showing the percentages of nitrogen and of phosphorus in
the nine samples of Hanford fine sandy loam.
nitrogen content, as compared with the San Joaquin series, than the
results show. The B and C horizons of the Hanford samples contain
0.038% and 0.028% nitrogen, respectively, showing that with the
increase of deriih there is a more rapid decrease of nitrogen than in
the San Joaquin samples, with the nitrogen content of the C horizon
of the Hanford only 0.002% above that of the C horizon of the San
398
University of California Publications in Agricultural Sciences [Vol. 3
Joaquin. The greenhouse pot cultures showed the effect of the much
higher nitrogen content in no. 14 in giving better color and growth
to the plants and especially to the grains. The increase of the nitrogen
in the surface of no. 23, as compared with the B and C horizons,
might be ascribed to the fertilizers applied to the orange grove where
this sample was collected; yet no. 24 is a truck soil which has been
fertilized to a considerable extent with barnyard manure. The nitro-
gen content of this type, as judged by the previous standards, is
quite inadequate.
Compare the nitrogen content of the A horizons of the four types :
The Diablo has an average of 0.099%, with a range or from 0.084%
to 0.117% ; the Altamont has an average of 0.110%, with a range of
from 0.103% to 0.123%; ; the San Joaquin has an average of 0.037%?,
with a range of from 0.027% to 0.050% ; and the Hanford has an
average of 0.062%, with a range of from 0.045% to 0.119%. Thus
the total nitrogen content of the several types is reasonably constant
within the type and rather distinct for the types.
Table 12-
-Total Nitrogen
Diablo Clay Adobe
Horizon
A
le
A
%
Average
%
B Average
% %
C
%
Average
%
0.109
0.105
0.076 0.069
0.056
0.057
0.101
0.063
0.059
0.100
0.072
0.062
0.084
0.092
0.064 0.068
0.058
0.060
0.085
0.065
No sample
0.084
0.084
0.065 0.065
0.114
0.097
0.075
0.122
0.118
0.107 0.102
0.083
0.079
iver
age
0.100
0.076
0.065
Sample
3
A
%
0.123
0.124
0.103
0.103
0.106
0.104
Table 13 — Total Nitrogen
Altamont Clay Loam
Horizon
Average
Average
%
0.123
0.103
0.105
0.110
B
%
0.089
0.087
0.054
0.053
0.070
0.077
Average
%
0.088
0.053
0.073
0.071
C
%
0.069
0.067
0.041
0.041
0.061
0.059
Average
%
0.068
0.041
0.041
0.060
0.056
1919]
Pendleton: A Study of Soil Types
399
Table 14 — Total Nitrogen
San Joaquin Sandy Loam
Horizon
Sample
A
%
Average
%
B
%
Average
%
C
%
Average
%
10
0.037
0.026
0.022
0.038
0.037
0.029
0.027
0.020
0.021
11
0.051
0.042
0.038
0.051
0.051
0.046
0.044
0.040
0.039
12
0.049
0.032
0.042
0.045
0.047
0.034
0.033
0.040
0.041
13
0.040
0.038
0.033
0.040
0.040
0.043
0.040
0.033
0.033
17
0.028
0.019
No sample
0.030
0.029
0.018
0.018
18
0.028
0.016
0.018
0.028
0.017
0.016
0.021
0.019
21
0.029
0.012
0.014
0.030
0.029
0.012
0.012
0.014
0.014
26
0.041
0.026
0.016
0.041
0.041
0.027
0.026
0.017
0.016
Average
0.038
0.027
0.026
Sample
14
15
16
19
20
22
23
24
25
Average
Table 15-
—Total
Nitrogen
Hanford
Fine Sandy Loam
Horizon
A
A
%
Average
%
B
%
Average
%
C
%
Average
%
0.113
0.084
0.060
0.126
0.119
0.081
0.082
0.057
0.058
0.052
0.039
0.028
0.055
0.053
0.043
0.041
0.027
0.028
0.058
0.030
0.020
0.054
0.056
0.030
0.023
0.021
0.046
0.025
0.024
0.023
0.044
0.045
0.025
0.025
0.023
0.023
0.062
0.032
0.024
0.058
0.060
0.034
0.033
0.022
0.023
0.057
0.033
0.025
0.061
0.059
0.036
0.034
0.023
0.024
0.075
0.028
0.020
0.071
0.073
0.030
0.029
0.016
0.018
0.050
0.032
0.034
0.028
0.028
0.045
0.031
0.022
0.047
0.046
0.032
0.031
0.024
0.023
0.062
0.038
0.027
400
University of California Publications in Agricultural Sciences [Vol. 3
Humus
Diablo clay adobe. — The variations in the humus content of the A
samples (table 16, and fig. 15) are moderate, 1.1% to 1.4%, while the
B and C horizons do not agree so closely with each other or with the
Loss on
Ignition
/
/
/
/
/
/
/
/
/
/
/
/
/
/
_.
/
/
—• — :: -~"
N>..
<■ -*K,
/
/.
X.
X
X
\
. —
2 .-__
MgO
K 2
Humus
■ CaO
Soils
Fig. 15. Graph showing the loss on ignition, the amount of humus, and
the percentages of calcium, magnesium, and potassium in the four samples
of Diablo clay adobe.
surface foot. The average content of humus in the A samples is
1.26%, in the B samples 0.95%, and in the C samples 0.75%. It is
worthy of note that soil no. 2, with the lightest color of the four, and
what might be supposed to be a lower humus content, has next to the
highest amount.
1919]
Pendleton: A Study of Soil Types
401
Altamont clay loam. — Here the variations in the humus content
(table 17, and fig. 16) are small in the A horizon, 1.1% to 1.3%. The
average is 1.24%. The B and C samples show a good parallelism
among themselves, but not so good when compared with the surface.
The average of the B horizon is 0.84%, and of the C horizon 0.57%.
\
\
V
y
/
/
/
/
^L-
/
Loss on
Ignition
K 2
Humus
CaO
MgO
3 4 7 Soils
Fig. 16. Graph showing the loss on ignition, the amount of humus, and the
percentages of calcium, magnesium, and potassium in the three samples of Alta-
mont clay loam.
San Joaquin sandy loam. — This type contains a considerable quan-
tity of humus (table 18, and fig. 17) when one takes into considera-
tion the popular criteria for the presence of humus, for the red to
reddish brown San Joaquin soils are very different from the brown
Altamont or the black Diablo soils. The samples of this type gave
40:
University of California Publications in Agricultural Sciences [Vol.3
light colored or nearly colorless humus solutions. But when the ali-
quots were ignited, after evaporation, there was a very noticeable
blackening and charring of the residue, together with a considerable
/
\
/
\
/
\
/
/
\
/
\
/
/ J
/
i \\
/
/
/
"v\
/
/
/
/
v
/
\ /
/
/
\\
Y
/
/
s
/
/
V
A
/ \
/ \
/
/ x
V-— ..
/
/
/
\
^^**».
\ /
\
\/
\
\
/ \
\
/
t- :
" **
....
^
\
""■:./
*««
... *"^»l
****■••—..
\,
y
•• <Sv ^
-><
y
"-N...
^
Loss on
Ignition
K2O
Humus
MgO
CaO
10
12
L3
17
IS
21 26 Soils
Fig. 17. Graph showing the loss on ignition, the amount of humus, and
the percentages of calcium, magnesium, and potassium in the nine samples of
San Joaquin sandy loam.
loss in weight. This phenomenon, in the light of the work of Gortner, 27
shows that these soils have a "humus" content above that which they
might be supposed to have, because of the almost complete absence of
27 soil Science, vol. 2 (1916), pp. 395-442.
1919] Pendleton: A Study of Soil Types 403
the "black pigment." Soil no. 26, probably the only virgin soil in
the series, shows a particularly high content of humus for such a soil,
though from the color of the soil one would suspect but very little
humus. The agreement between the three horizons of the San Joaquin
sandy loam samples is close. The average content of humus was
0.68% in the A, 0.51% in the B, and 0.38% in the C horizon.
Han ford fine sandy loam. — The variations in humus content in this
type are greater than in any of the others (table 19, and fig. 18). This
is possibly because of two factors : the open texture of the soil, hence
the rapid loss of organic matter by oxidation processes ; and secondly,
the high agricultural value of this soil, which has led to a greater appli-
cation of fertilizers than has been the case with the other soils. The
actual variations in the humus content are large, 0.7% to 2.1% with
the average of 1.15% for horizon A, from 0.5% to 1.8% with the aver-
age of 0.81% for B, and from 0.44% to 1.07% with the average of
0.59% for C. The extra-typical sample no. 14 is above any of the
others in the total humus content. The variations in the subsoil
humus content are more or less parallel to those of the surface soil.
The following averages of the humus content of horizon A, Diablo
1.26%, Altamont 1.24%, San Joaquin 0.68%, Hanford 1.15%, show
that there is not much difference between the soils, except for the San
Joaquin sandy loam, which has an average of half the others. Within
the type the soils may be nearly alike, as in the San Joaquin and Alta-
mont, or may be variable to a large degree, as in the Hanford. The
variations in the humus content of the soils are small, considering the
diverse nature of the soils, and the usual methods for judging the
quantity of humus.
Table 16 — Humus (and Humus Ash)
Diablo Clay Adobe
Humus
Horizons
A
Humus ash
Horizons
A
Sample
A
%
Average
%
B
Average C
% %
Average
%
A Average
% %
B
%
Average
%
C
%
Aver-
age
%
1
1.08
0.51
0.18
0.55
0.75
0.45
1.08
1.08
0.51
0.51
0.24
0.21
0.56
0.56
0.73
0.74
0.46
0.46
2
1.40
1.16
1.09
1.01
0.96
1.09
1.38
1.39
1.15
1.15
1.02
1.06
1.03
1.02
0.96
0.96
0.96
1.03
5
1.17
0.87
1.08
1.19
1.12
1.15
0.91
0.89
1.10
1.09
1.14
1.17
6
1.48
1.26
0.95
0.98
0.88
0.78
Werag
1.37
3
1.43
1.26
1.26
1.26
0.95
0.99
0.97
0.72
0.95
0.96
0.91
0.91
0.90
0.95
0.85
0.81
0.77
404
%
University of California Publications in Agricultural Sciences [Vol. 3
Humus
14 15 H> 19 20 22 23 24 25 Soila
Pig. 18. Graph showing the loss on ignition, the amount of humus, and
the percentages of calcium, magnesium, and potassium in the nine samples of
Hanford fine sandy loam.
1919]
Pendleton: A Study of Soil Types
405
Table 17 — Humus (and Humus Ash)
Altamont Clay Loam
Humus
Horizons
A Average B Average C Average
Sample % % % % % %
3 1.06 0.89 0.59
1.13 1.09 0.84 0.86 0.58 0.59
4 1.30 0.69 0.59
1.33 1.31 0.71 0.70 0.28 0.43
7 1.32 0.95 0.68
1.31 1.32 0.96 0.96 0.68 0.68
Average 1.24 0.84 . 0.57
Humus ash
Horizons
Aver-
A Average B Average C age
% % % % % %
1.29 1.08 0.95
1.23 1.26 1.28 1.18 0.95 0.95
0.80 0.98 0.91
0.85 0.83 0.98 0.98 1.03 0.97
0.72 0.87 1.09
0.75 0.74 0.88 0.88 1.08 1.08
0.94 1.01 1.00
Table 18 — Humus (and Humus Ash)
San Joaquin Sandy Loam
Humus
Horizons
A
Humus ash
Horizons
A
Sample
A Average
% %
B Average
% %
C Average
% %
A Average
% %
B Average
% %
C
%
Aver-
age
%
10
0.66
0.66
0.53
0.53
0.27
0.27
1.31
1.31
1.33
1.33
0.67
0.67
11
0.75
0.41
0.37
0.51
0.66
0.58
0.71
0.73
0.41
0.37
0.69
0.60
0.66
0.58
12
0.62
0.49
0.32
0.88
1.50
0.80
0.65
0.64
0.49
0.32
0.95
0.91
1.50
0.80
13
0.75
0.50
0.35
1.38
0.90
1.02
0.78
0.77
0.50
0.35
1.36
1.37
0.90
1.02
17
0.51
0.51
0.51
0.38
0.38
0.53
0.57
0.55
1.23
1.23
18
0.56
0.60
0.42
0.61
0.76
1.79
0.60
0.58
0.58
0.59
0.42
0.56
0.59
0.75
0.76
1.79
21
0.52
0.19
0.18
0.53
0.37
0.37
0.52
0.52
0.21
0.40
0.21
0.19
0.54
0.53
0.37
0.37
0.48
0.42
26
1.04
0.79
0.68
0.89
3.57
5.28
1.01
1.02
0.79
0.79
0.82
0.75
0.76
0.83
3.63
3.60
5.46
5.35
Average
0.66
0.51
0.38
0.83
1.24
1.51
Excluding no.
26
0.95
0.87
Loss on Ignition
The loss on ignition of the A horizon varies directly with the tex-
ture of the soil, the heavier soils losing more on heating. Obviously
the water of combination of the clay is a large factor in this loss. In
the San Joaquin sandy loam the loss on ignition was determined in
the three horizons. In the other three types the A horizon was the
only one examined (tables 20, 21, and figs. 15-18).
406
University of California Publications in Agricultural Sciences [Vol. 3
Table
19 — Humus
(and
Humu
s Ash
.
Hanford Fin
,e Sandy Loam
Humus
Horizons
Humus ash
Horizons
Sample
A
%
Average B
% %
Average C
% %
Average
A Average
% %
B Average
% %
C
%
Aver-
age
%
14
2.11
1.81
1.10
1.14
1.24
1.01
2.09
2.10
1.78
1.79
1.05
1.07
1.17
1.16
1.27
1.26
1.09
1.05
15
1.79
0.88
1.04
1.88
0.94
0.92
1.77
1.78
0.93
0.90
0.67
0.86
1.85
1.86
0.89
0.92
0.91
0.92
16
1.20
0.73
0.41
0.91
0.93
0.90
1.20
1.20
0.73
0.73
0.46
0.44
0.91
0.91
1.47
0.93
0.90
0.90
19
0.73
0.51
0.45
0.48
0.57
0.78
0.74
0.73
0.50
0.51
0.55
0.50
0.47
0.48
0.58
0.58
0.76
0.77
20
1.08
0.86
0.59
0.52
0.90
0.79
1.06
1.07
0.89
0.88
0.50
0.55
0.56
0.54
0.90
0.90
0.78
0.78
22
0.96
0.73
0.58
0.59
0.60
0.58
0.96
0.96
0.71
0.72
0.56
0.57
0.59
0.59
0.60
0.60
0.63
0.61
23
1.04
0.59
0.38
0.58
0.45
0.39
1.07
1.05
0.62
0.61
0.38
0.38
0.57
0.58
0.41
0.43
0.37
0.38
24
0.73
0.55
0.56
0.58
0.69
0.82
0.73
0.73
0.61
0.58
0.51
0.54
0.56
0.57
0.69
0.69
0.80
0.81
25
0.71
0.58
0.45
0.57
0.67
0.74
0.69
0.70
0.56
0.57
0.42
0.44
0.61
0.59
0.71
0.69
0.78
0.76
Average
1.15
0.82
0.59
0.81
0.78
0.78
Diablo clay adobe. — The variation in these samples was from
5.6% to 8.6%, with the average of 6.8%. The Altamont clay loam
has a variation of from 5% to 8.7%, averaging 6.7%. The San Joa-
quin sandy loam has a range of variation between 1.6% and 4.2%,
with an average of 2.6%. The loss on ignition of the lower horizons
increases over that of the surface, because of the increase in texture.
The B horizon shows an average loss of 3.9% and the C horizon of
4.67%. The Hanford fine sandy loam range of variation in the loss
on ignition is, excluding no. 14, from 2.2% to 3.9%, with an average
of 3.4%. Thus the curve for this type is quite uniform, except for
no. 14, which shows a loss of 6.9%.
It is seen that the averages in the loss on ignition of the A horizons
of the Diablo and Altamont soils are close, and high, 6.8% and 6.7%
respectively. The averages of the San Joaquin and Hanford sam-
ples, 2.6% and 3.4% respectively, are low and not widely separated.
Since the values for the types overlap considerably, and the averages
are not distinct, except between the light and heavy groups, there is
no significant distinction between the four types by this determination.
1919]
Pendleton: A Study of Soil Types
407
Table 20 — Loss on Ignition
(Surface horizon only)
Diab
lo Clay Adobe
A *
%
Altamont Clay
%
Loam
%
Hanford Fine
Loam
A
Sandy
^
%
%
1-A
6.62
3-A
8.74
14-A
6.90
6.66
6.64
8.82
8.78
6.95
6.92
2-A
6.57
4-A
5.05
15-A
2.27
6.64
6.60
5.05
5.05
2.30
2.28
5-A
5.61
7-A
6.58
16-A
3.26
5.61
6.46
6.52
3.24
3.25
6-A
8.67
8.71
8.69
A
verage
6.78
19- A
3.10
3.13
3.11
Average
6.88
20-A
3.90
3.94
3.92
2 2-A
3.06
3.07
3.06
23-A
3.48
3.45
3.46
24-A
2.60
2.60
2.60
2 5-A
2.68
2.72
2.70
Average
3.48
Table 21 — Loss on Ignition
San Joaquin Sandy Loam
Sample
A
%
Average
%
10
2.13
2.17
2.15
11
3.23
3.20
3.21
12
5.37
3.22
4.29
13
2.94
2.96
2.95
17
1.85
1.88
1.86
18
1.82
1.83
1.82
21
1.68
1.69
1.68
26
3.30
3.30
Avera
ge
2.66
Ho
rizon
A
B
%
Average
%
2.32
2.27
2.29
6.33
6.16
6.24
2.97
3.18
3.07
6.58
6.75
6.66
2.54
2.61
2.57
2.18
2.18
2.18
1.60
1.56
1.58
6.97
6.95
6.96
3.94
c
%
3.10
3.08
6.57
6.67
Average
3.09
6.62
5.54
5.54
3.97
6.07
5.02
NO!
sample
2.90
2.89
2.89
3.31
3.33
3.32
6.18
6.18
4.67
408 University of California Publications in Agricultural Sciences [Vol. 3
Calcium
The Diablo, Altamont, and Hanford soils were analyzed for their
calcium in the A horizon only, while the A, B, and C horizons of the
San Joaquin sandy loam were analyzed (tables 22, 23, and figs. 15-18).
Diablo clay adobe. — There is much divergence in the amounts of
CaO in this type, varying from 0.36% to 2.05%, with the average
of 1.23%.
Altamont clay loam. — In this type there is a little greater varia-
tion than in the Diablo samples, with a range of from 0.78% to 5.64%,
averaging 2.44% CaO. In both this soil and in the Diablo the wide
variation in the lime content is undoubtedly due to the nature of the
parent rock, since the soils are residual:
San Joaquin sandy loam. — In the CaO content there is no uni-
formity among the samples. The A samples of this type contain from
0.47% to 2.98%, with an average of 1.65%. It would seem that the
materials from which the soils were derived were of varying composi-
tion. For from the present climatic conditions soil no. 25 is the one
subject to the least leaching, and yet has the least CaO content. The
B and C percentages follow the surface very closely — sufficiently so
to necessitate no particular explanation. The range of variation in
the B horizon is from 0.11% to 2.42%, and the average is 1.42%.
The C samples vary from 0.17% to 2.81%, with the average of 1.52%.
Hanford fine sandy loam. — The A samples of this type contain
from 2.56% CaO to 4.69%, with 3.33% as the average. The varia-
tions are not so marked among the series of this type as in the cases
of the other three soils. The absolute range is nearly as great, but
the relative variation is less.
Even though there are differences between the average CaO con-
tent in the several types, the wide variation in the amount found in
the several samples of a given type, and the overlapping of these
amounts from the different types entirely preclude any statement
that as regards the calcium content the soils of any one type are
closely similar to one another, or that one type has a higher or lower
lime content than another.
1919]
Pendleton: A Study of Soil Types
409
Table 22 — Calcium as CaO
(Surface horizons only)
Bh
iblo Clay Adobe
A
%
Altamont Clay
A
Loam
Hanford Fine
Loam
Sandy
r ~
%
%
%
%
1-A
1.86
3-A
5.64
14-A 2.91
1.80
1.83
5.64
2.99
2.95
2-A
2.12
4-A
0.92
15-A 2.98
1.98
2.05
0.88
0.90
3.22
3.10
5-A
0.56
7-A
0.89
16-A 2.48
0.17
0.36
0.67
0.78
2.65
2.56
6-A
0.67
0.67
A
verage
2.44
19-A 3.28
3.17
3.22
Average
1.23
20-A 2.69
2.73
2.71
22-A > 3.80
3.92
3.86
23-A 2.88
3.00
2.94
24-A 3.88
4.00
3.94
25- A 4.58
4.80
4.69
Average
3.33
Table 23 — Calcium as CaO
San Joaquin Sandy Loam
Horizon
Sample
r
A
%
Average
%
B
Average
%
C
%
Average
%
10
0.67
0.82
1.11
0.62
0.64
1.03
0.92
1.12
1.11
11
1.94
1.62
1.65
1.26
1.60
1.70
1.66
1.55
1.60
12
3.12
2.21
2.61
3.50
3.31
2.21
3.01
2.81
13
2.83
2.38
2.46
3.13
2.98
2.46
2.42
2.79
2.62
17
1.83
1.92
No
sample
2.08
1.95
2.08
2.00
18
1.40
1.00
1.48
1.34
1.37
1.45
1.22
1.42
1.45
21
0.91
0.89
0.85
0.84
0.87
0.83
0.86
0.89
0.87
26
0.48
0.13
0.17
Avei
0.47
age
0.47
1.65
0.10
0.11
1.42
0.17
0.17
1.52
410
University of California Publications in Agricultural Sciences [Vol. 3
Magnesium as MgO
Diablo clay adobe. — This type shows a moderate variability in the
magnesium content, with from 1.13% MgO to 3.26%, averaging
2.09%. The largest quantity is three times that of the smallest,
(tables 24, 25, figs. 15-18).
Altamont clay loam. — Within the three samples of this type the
range in the MgO content is very great, from 0.07% to 1.90%, with
the average of 1.05%. The largest is twenty-seven times that of the
smallest.
San Joaquin sandy loam. — The total MgO in the samples of the
type is low, considering that some soils reported by Hilgard contain
from 1% to 3% magnesia by the acid digestion. The variation within
the A horizon is from 0.34% to 0.90%, with the average of 0.62%, i.e.,
the largest is three times the smallest. The quantities in the B horizon
are somewhat erratic as compared with those of the surface, yet in
both the B and C horizons the results approach those of the surface
sufficiently to give a rough parallelism. The greater amount of clay
and fine silts with the increase of depth gives, as one would expect,
an increase of magnesium. The average MgO content in the B horizon
is 0.81%, and in the C horizon 1.05%.
Table 24 — Magnesium as MgO
(Surface horizon only)
Diablo Clay Adobe
j
ytamont Clav
A
Loam
Hani
'ord Fine S
Loam
A
andy
r
%
%
%
%
%
%
1-A
1.64
3-
-A
1.85
14- A
2.49
2.20
1.92
1.95
1.90
2.49
2.49
2-A
2.16
4-
-A
1.21
15-A
0.93
1.95
2.05
1.17
1.19
1.02
0.97
5-A
1.23
7-
-A
0.09
16-A
1.10
1.03
1.13
0.05
0.07
0.99
1.04
6-A
3.62
2.90
3.26
A
verage
1.05
19- A
2.11
1.99
2.05
Average
2.09
20- A
1.77
1.92
1.84
22-A
2.44
2.71
2.57
23-A
1.94
1.70
1.82
24-A
2.14
2.13
2.13
25-A
2.31
2.40
2.35
Average
1.92
1919]
Pendleton: A Study of Soil Types
411
Han ford fine sandy loam. — The MgO content of the surface soil
varies from 0.97% to 2.57%, averaging 1.92%. The relative varia-
tion within this type is about that of the Diablo and San Joaquin
types.
Comparing the average amounts of magnesium oxide in the sur-
face horizon of the several types, we find the San Joaquin with 0.56%,
the Altamont with 1.05%, the Hanford with 1.93%, and the Diablo
with 2.09%. The averages do not signify much, however, because of
the wide ranges within the types. Therefore as regards magnesium
the types are neither distinct nor are the soils within the type
closely similar.
Table 25 — Magnesium as MgO
San Joaquin Sandy Loam
Horizon
Sample
A
%
Average
B
%
Average
%
C
%
Average
%
10- A
0.31
0.33
0.53
0.30
0.30
0.45
0.39
0.53
0.53
11-A
0.79
1.21
1.48
0.44
0.61
1.22
1.21
1.25
1.36
12- A
0.83
0.79
1.57
0.79
0.81
0.79
1.62
1.59
13- A
0.90
1.70
1.67
0.80
0.85
1.63
1.66
1.82
1.74
17- A
0.53
0.51
No sample
0.74
0.63
0.77
0.64
18-A
0.50
0.40
0.64
0.48
0.49
0.69
0.54
0.75
0.69
21-A
0.29
0.28
0.52
0.29
0.31
0.29
0.56
0.54
26-A
0.50
0.52
0.52
0.52
0.51
0.44
0.48
0.53
0.52
Average
0.56
0.75
1.00
Phosphorus as P 2 5
Diablo clay adobe. — The variations in the P 2 5 content in the
samples of this type are relatively small, from 0.092% to 0.162%,
with 0.108% as the average (tables 26, 27, figs. 11-14).
Altamont clay loam. — The range of variation in the amount of
P 2 5 is large, from 0.031% to 0.265%, the largest quantity being eight
times the smallest. The average is 0.132%.
412 University of California Publications in Agricultural Sciences [Vol. 3
San Joaquin sandy loam. — The variations in the P 2 5 content of
the surface soil are from 0.039% to 0.11%, with the average 0.068%.
The curve is fairly regular. The subsoils follow the surface in a gen-
eral way. The B horizon samples vary in the phosphoric acid con-
tent between 0.028% and 0.156%, and average 0.069%. The C sam-
ples vary between 0.03% and 0.109%, and average 0.067%. The
averages of the three horizons are seen to be almost identical. No
particular significance can be attached to the minor variations.
Hanford fine sandy loam. — The P 2 5 content in the samples of
this type is very variable, from 0.195% to 0.819%, with the average
of 0.363%. The average of the San Joaquin sandy loam samples is
0.069%, of the Diablo clay adobe 0.108%, of the Altamont clay loam
0.132%, and of the Hanford fine sandy loam 0.363%. Except between
the Diablo and Altamont types these averages would show considerable
differences, if it were not that the samples frequently show such wide
departures from the averages. The ranges of the several types fre-
quently overlap.
Table 26 — Phosphorus as P 2 5
(Surface horizon only)
Hanford Fine Sandy
Diablo Clay Adobe Altamont Clay Loam Loam
A . „ A . A .
% % % % % %
1-A 0.088 3-A 0.278 14-A 0.373
0.096 0.092 0.252 0.265 0.292 0.333
2-A 0.064 4-A 0.081 15-A 0.287
0.078 0.071 0.117 0.099 0.260 0.273
5-A 0.137 7-A 0.034 16-A 0.260
0.082 0.109 0.028 0.031 0.277 0.268
6-A 0.143 Average 0.132 19-A 0.303
0.181 0.162 0.272 0.287
Average 0.108 20-A 0.190
0.200 0.195
22-A 0.397
0.401 0.399
23-A 0.242
0.270 0.256
24- A 0.421
0.454 0.437
25-A 0.879
0.759 0.819
Average 0.363
1919]
Pendleton: A Study of Soil Types
413
Table 27-
-Phosphorus as P 2 5
San Joaquin Sandy Loam
Horizon
A
Sample
A
%
Average
%
B
%
Average
%
C
%
Average
%
10
0.118
0.060
0.047
0.102
0.110
0.068
0.064
0.057
0.052
11
0.049
0.047
0.049
0.060
0.054
0.046
0.046
0.028
0.028
12
0.057
0.028
0.064
0.071
0.064
0.028
0.095
0.078
13
0.049
0.037
0.036
0.064
0.056
0.038
0.039
0.024
0.030
17
0.036
0.041
No sample
0.042
0.039
0.082
0.061
18
0.043
0.097
0.086
0.055
0.049
0.074
0.085
0.086
21
0.069
0.088
0.094
0.068
0.068
0.066
0.077
0.062
0.078
26
0.117
0.130
0.120
0.092
0.104
0.182
0.156
0.098
0.109
Average
0.068
0.069
0.067
Potassium as K 2
Diablo clay adobe. — There is a moderate range in the variation in
the amount of K 2 within this type, the lowest amount being 1.48%
and the highest 2.06%, the four samples averaging 1.71% (table 28,
figs. 15-18).
Altamont clay loam. — A greater variation, from 1.09% to 2.14%,
of K 2 0, occurs in the three samples of this type. The average is
1.74%.
San Joaquin sandy loam. — This type shows the greatest variation,
from 0.98% to 2.84%. But even so, the the largest quantity of K 2
is less than three times the smallest. 1.88% K 2 is the average of
the eight samples. Nos. 11 and 12 of this type show the smallest
amounts of K 2 of any of the twenty-four samples.
Hanford fine sandy loam. — The variation in the K 2 content of
the samples of this type is not great — from 1.73% to 3.16%, with
the average of 2.33%. This is the highest average, as the Diablo clay
adobe samples show 1.71%, the Altamont clay loam 1.74%, and the
San Joaquin sandy loam 1.88%. Because of the considerable range
in the amounts of K 2 for the several samples of a type, and because
of the many overlappings of the values for one type over another,
the averages do not mean much and do not show the soils within a
type to be closely similar, nor do they show the types distinct.
414 University of California Publications in Agricultural Sciences [Vol. 3
Table 28 — Potassium as K 2
(J. Lawrence Smith Method)
Hanford Fine Sandy
Dii
iblo Clay
Adobe
Altamont Clay
Loam
San Joaqu
in Sandy Loam
Loam
No.
%
Average
%
Xo.
%
Average
%
No.
%
Average
%
r
No.
Average
%
1-A
1.68
3-A
1.06
14-A
1.79
10- A
2.14
1.67
1.67
1.13
1.09
1.67
1.73
2.12
2.13
2-A
1.62
4-A
1.92
15-A
2.54
11-A
0.99
1.69
1.65
2.36
2.14
2.62
2.58
0.98
0.98
5-A
1.45
7-A
1.90
16-A
2.42
12-A
1.03
1.51
1.48
2.10
2.00
2.46
2.44
1.02
1.02
6-A
2.01
2.12
2.06
A
verage
1.74
I9-A
2.10
2.03
2.06
13-A
1.50
1.50
Average
1.71
20- A
2.00
17-A
2.40
1.81
1.90
2.24
2.32
2 2-A
2.68
2.62
2.65
18-A
2.07
2.28
2.17
23-A
3.10
3.23
3.16
2 1-A
2.81
2.88
2.84
24-A
2.29
2.21
2.25
2 6-A
2.04
2.09
2.06
25-A
2.18
Average
1.88
2.21
2.19
Average
2.33
Bacteriological Data
The bacteriological work was not entirely satisfactory, partly be-
cause the conditions in one of the incubators were not all that might
be desired, and partly because of the refractory physical properties
of some of the soils. The Diablo and Altamont types, in all three
horizons, were very heavy and hard to mix and keep in even fair
physical condition. The San Joaquin soils were predominantly of a
heavy texture in the B and C horizons, while the surface horizon
was light and the crumb structure was entirely lost if even a small
excess of water was added to the culture.
AMMONIFI CATION
There arc very marked differences between the various types in
tli is determination, though the samples in a given type vary among
themselves to a large extent.
Diablo clay adobe. — The highest ammonia production was about
three limes the lowest, 7.7 mg. and 26 mg. In both this type and
the following, the B and C horizons follow the surface horizon quite
1919]
Pendleton: A Study of Soil Types
415
-a
£ 40
O
^ 30
n
X
z
S 20
\ \
— - ^—
N
°l £ 5. 6
Soi Is.
Fig. 19-A.
Fig. 19a. Graph showing ammonification in the four samples of Diablo clay
adobe. The quantities are expressed in terms of nitrogen produced per 100
grams of soil with 2% of dried blood.
x
71
\Q
15
SO
25
\
^
A
B^^^"
JZ^~ """"
~^c
A Z. O 6.
Soils.
Fiq. 13 -B
Fig. 19b. Graph showing nitrogen fixation in the three horizons of the four
samples of Diablo clay adobe. The quantities are expressed in terms of milli-
grams of nitrogen fixed per gram of mannite in 50 grams of soil.
416
University of California Publications in Agricultural Sciences [Vol. 3
closely from sample to sample (table 28 and fig. 19a). This may be
due to the textures, which are quite similar throughout the soil column.
The averages for the three horizons were : A, 18.6 mg. ; B, 12.6 mg. ;
and C, 8.9 mg.
30
20
10
3 4 7 Soils
Mg N. as NH3 Produced
Fig. 20a. Graph showing ammonifieation in the three horizons of the three
samples of Altamont clay loam.
10.
7.5
B
\
\
\
V
N
\
\
W
\
\
2.5
3 4 7 Soils
Mg N. Fixed
Fig. 20b. Graph showing nitrogen fixation in milligrams in the three horizons
of the three samples of Altamont clay loam.
Altamont clay loam. — As regards horizon A the amount of am-
monia produced in one soil is three times that in the lowest, 10 mg.
nitrogen and 33 mg. nitrogen as ammonia, with 8.9 mg. as the average
(table 30 and fig. 20a). The amount of nitrogen as ammonia pro-
duced in the B horizon averaged 12.6 mg., in the C horizon 8.9 mg.
1919]
Pendleton: A Study of Soil Types
417
San Joaquin sandy loam. — The amount of ammonia produced in
the A horizon varied between 30.4 mg. of nitrogen and 57.1 mg., the
average was 40.2 mg. (table 31 and fig. 21a). The production of
ammonia, in milligrams of nitrogen, by the B samples varied between
4.5 mg. and 38.1 mg., with 20 mg. as the average. In the C samples
the variation was nearly as great, between 5.7 mg. and 32 mg., with
the average of 20.9 mg. Thus there are notable variations among the
12 13 17 18 21 26 Soils
Mg N. as NH3 produced
Fig. 21a. Graph showing ammonification in the three horizons of the eight
samples of San Joaquin sandy loam.
samples of this type, the proportional variation being very great, con-
sidering the three horizons. Possibly the reason that the B and C
horizons are so divergent from the surface is that there is a very
marked variation in the texture between the surface horizon and
those below the surface.
Hanford fine sandy loam. — The variation is large here also (table
32, fig. 22a), the largest quantity of ammonia produced in the surface
soil is twice that of the smallest production, 72 mg. and 35 mg. The
subsoil variations, in a general way, parallel those of the surface.
The average production of ammonia in the three horizons is as fol-
418
University of California Publications in Agricultural Sciences [Vol. 3
lows: A, 56.9 mg. nitrogen; B, 46.3 mg. nitrogen; and C, 38.7 mg.
nitrogen. In attempting to correlate the variations in ammonifying
powers with the known variations of the soils, or with the known his-
tories of the soils, there seem to be no relations of significance.
The Altamont and Diablo types are about alike in their low am-
monifying power. The Hanford and San Joaquin are both higher
and nearer to each other than to the two heavy types, yet the Hanford
is noticeably higher than the San Joaquin. This is as one would ex-
pect, from a knowledge of the soils in the field. Considering the types
as a whole, as represented by the A horizon, there are more marked
variations between the types than between the samples of a given type
though the variations within a given type are very large.
Average
Table 29 — Ammonification
Diablo Clay Adobe
Milli
grams N as
NH 3 Pi
-oduced
A
A
B
C
(
Cultures
Checks
average
Increase
over
checks
Cultures
Checks
average
Increase
over
checks
r
Cultures
Increase
Checks over
average checks
31.48
28.58
24.24
40.32
2.52
33.38
22.98
2.28
23.50
14.99
2.42 17.19
19.81
9.45
8.41
17.07
1.68
16.76
9.84
1.91
7.73
9.95
1.05 8.13
15.90
11.55
No sample
1.75
14.15
12.54
1.54
10.50
12.33
7.76
12.33
3
2.11
10.22
18.63
13.55
2.07
8.58
12.58
12.33
2.03 10.30
11.87
Table 30 — Ammonification
Altamont Clay Loam
Milli;
grams N as
NH 3 Pi
reduced
A
A
B
A
C
Sample
r
Cultures
Checks
average
> >
Increase
over
checks
Cultures
Checks
average
Increase
over
checks
Cultures
Checks
average
>
Increase
over
checks
3
8.14
6.97
5.89
10.58
1.68
7.68
7.15
1.40
5.16
4.91
1.54
3.86
4
19.75
6.59
5.41
19.12
2.66
16.77
6.67
1.36
5.27
5.12
1.19
4.07
7
28.66
19.66
8.00
27.53
2.03
26.06
1 6.25
1.75
16.20
12.37
1.33
8.95
Average
16.84
8.88
5.63
1919]
Pendleton: A Study of Soil Types
419
Table 31 — Ammonification
San Joaquin Sandy Loam
Milligrams N as NH 3 Produced
B
Sample
10
Cultures
54.24
Checks
average
Increase
over
checks
r
Cultures
42.63
Checks
average
Increase
over
checks
r
Cultures
28.89
1
Checks
average
>
ncrease
over
checks
41.95
1.72
46.73
36.11
1.28
38.09
38.25
1.59
31.98
11
44.47
7.47
6.05
73.23
1.70
57.15
12.52
1.81
8.18
6.78
1.68
4.78
12
44.48
18.73
10.91
40.07
1.56
40.71
21.81
1.50
18.77
6.11
1.14
7.87
13
41.66
5.41
3.80
45.04
1.30
42.50
5.36
0.86
4.52
15.17
0.88
8.60
17
30.19
27.59
No sample
33.88
1.66
30.37
20.68
1.51
22.62
18
35.04
30.56
21.96
35.24
1.48
33.66
22.81
1.30
25.38
16.92
1.47
17.97
21
34.44
37.41
25.72
30.89
1.48
31.18
37.74
1.38
36.19
29.66
1.42
26.27
26
40.81
7.50
9.08
1.64
39.17
8.41
1.44
6.51
5.43
1.54
5.71
A vera s
:e
40.18
20.03
12.89
Table 32 — Ammonification
Hanford Fine Sandy Loam
Milligrams N as NH 3 Produced
B
Sample
Cultures
Checks
average
Increase
over
checks
r
Cultures
Checks
average
Horizons
Increase
over
checks
r
Cultures
Checks
average
Increase
over
checks
14
37.35
27.96
14.39
43.57
1.78
38.68
48.46
1.46
36.75
41.70
1.24
26.80
15
33.11
45.68
59.90
41.75
1.75
35.68
48.38
1.70
45.33
52.59
1.62
54.62
16
56.59
44.08
44.58
56.77
1.83
54.85
42.10
1.61
41.48
52.10
1.69
46.65
19
52.92
46.70
24.56
51.85
1.47
50.91
38.92
1.13
41.68
28.12
1.24
25.10
20
72.49
45.49
22.05
74.21
1.36
71.99
38.52
1.03
40.97
30.35
1.00
25.20
22
64.92
57.44
46.08
67.56
1.75
64.49
55.34
1.51
54.88
47.55
1.60
45.21
23
71.56
50.84
35.15
68.66
1.61
68.50
43.01
1.37
45.55
35.23
1.35
33.84
24
65.02
50.09
37.56
59.51
1.50
60.76
46.54
1.32
46.99
40.21
1.33
37.55
25
68.20
69.29
61.01
67.29
1.43
66.31
60.03
1.25
63.41
47.70
1.22
53.13
Average
56.91
46.34
38.67
420
University of California Publications in Agricultural Sciences [Vol. 3
Nitrogen Fixations
Diablo clay adobe. — This type shows the highest quantity of nitro-
gen fixed, 9.6 m'g., with the subsoil quantities, much lower than the
surface. The variation within the type is seen to be the largest of that
in any of the types.
Altamont clay loam. — The surface samples have 1.0, 4.7, and 9.1
mg. nitrogen (table 34 and fig. 20b). The soils shows a wide diver-
gence between the surface samples and between the surface and sub-
soils. This is to be expected in the heavier soils.
7.5
C
2.3
\
\ 7*
\
\
\ \
\
\
\
X
______ _^^+
^
10
11
12
13 17
Mg N. Fixed
IS
21
26 Soils
Fig. 21b. Graph showing nitrogen fixation in the three horizons of the
eight samples of San Joaquin sandy loam.
San Joaquin sandy loam. — The quantity fixed in the A horizon
(table 35 and fig. 21b) is small and quite variable. It is between
nothing and 5.5 mg., with the average of 1.9 mg. Instead of nitrogen
fixation denitrification took place in a number of cases, especially in
horizon C. Considering the wide variation in textures of the horizons,
it is rather odd that there should not be a greater variation between
the soils from the various depths.
Han ford fine sandy loam. — The amount of nitrogen fixed by the
surface soil (table 36, and fig. 22b) averages much higher, 5.7 mg.,
than that in the San Joaquin sandy loam, though the range of varia-
tion is about the same. It is noticeable that the amounts of nitrogen
fixed by the B and C horizons of the soils nos. 14 and 19 are much
28 All of the figures on nitrogen fixation refer to the milligrams of nitrogen
fixed per gram of mannite in 50 grams of soil (table 33 and figs. 9-13).
1919]
Pendleton : A Study of Soil Types
421
less (even to denitrification) absolutely and relatively as compared
with the surface horizons, than the amount fixed by the B and C
horizons of the soils nos. 20 to 25 inclusive.
Comparing the nitrogen fixation of the various types, there seem
to be no characteristic differences between the heavy Altamont and
Diablo types, while the lighter Hanford and San Joaquin types are
considerably different from each other. As a whole there is but a fair
degree of similarity between the samples of a given type. The degree
of variation within types is large.
Table
33 — Nitrogen Fixation
Diablo Clay Adobe
Millisri
ams N per
gram of
mannite
A
A
B
A
C
A
Sample
f
Cultures
Checks
average
Increase
over
checks
Cultures
Checks
average
Increase
over
checks
r
Cultures
Checks
average
Increase
over
checks
1
60.25
31.52
22.77
63.40
52.22
9.60
29.56
34.67
-4.13
24.87
28.61
-4.79
2
55.34
32.92
30.47
49.39
45.88
6.48
38.18
33.80
1.75
32.22
29.77
1.57
5
48.68
35.73
No sample
48.68
41.92
6.76
37.12
32.39
4.03
6
45.88
39.64
35.02
46.86
58.49
-12.12
42.72
50.77
-9.59
39.01
39.05
-2.03
Average
4.71
1.44
0.52
Table 34 — Nitrogen Fixation
Altamont Clay Loam
Milligrams N fixed per gram of mannite
B
Sample
Cultures
Checks
average
Increase
over
checks
r
Cultures
Checks
average
Increase
over
checks
r
Cultures
Checks
average
Increase
over
checks
3
71.26
49.04
37.13
70.40
61.71
9.12
51.84
43.78
6.66
38.51
33.76 .
4.06
4
60.25
28.02
20.31
52.19
51.49
4.73
27.32
26.48
1.19
21.01
20.48
0.18
7
52.95
37.75
30.81
53.44
52.12
1.08
37.40
36.60
1.00
27.18
29.94
-0.94
Average
4.98
2.95
1.41
422 University of California Publications in Agricultural Sciences [Vol. 3
7d
:.o
40
30
20
10
.
/^/
1
1
1
N /
N /
S /
/
\
\
/
/'«
/ /
t
1
1
1/
/ \
\
\
— *—
/
/ ,
/ /
X
\
\
\
N
\
-— -""
/ /
/
/
/
/
/
/
/
\
\
\
\
\
\
/
/
/
/
/
/
\
\
\
\
^"
/
/
<
\
\
>
/
/
-
15
16
23
24
19 20 22
Mg N. as NH3 produced
Fig. 22a. Graph showing ammonification in the three horizons of the nine
samples of Hanford fine sandy loam.
26 Soils
10
7.5
2.5
//
\\
\\
/
><
s
//
/
/
/
1
l \
23
21
15 16 19 20 22
Mm N. Fixed
Pig. 22b. Graph showing nitrogen fixation in the three horizons of the nine
sum pies of Hanford fine sandy loam.
25 Soils
1919]
Pendleton: A Study of Soil Types
423
Table 35 — Nitrogen Fixation
San Joaquin Sandy Loam
Milligrams N fixed per gram of mannite
A
A
B
A
C
Sample
Cultures
Checks
average
Increase
over
checks
r
Cultures
Checks
average
Increase
over
checks
r
Cultures
Checks
average
Increasi
over
checks
10
25.01
17.16
15.83
23.47
18.73
5.51
16.67
13.59
3.32
18.14
10.33
6.65
11
27.25
22.91
21.72
31.87
25.15
4.41
22.84
21.78
1.09
22.00
19.43
2.43
12
25.85
20.17
18.98
23.82
23.26
1.57
17.09
16.56
2.07
20.10
20.41
-0.87
13
22.77
18.49
13.31
21.58
20.00
2.17
17.86
20.21
-2.04
14.50
16.35
-2.45
17
13.52
13.45
9.46
10.23
No samp]
[e
18
15.55
8.76
9.18
13.24
13.73
0.66
8.20
8.09
0.39
11.42
9.74
0.56
21
14.85
7.98
6.58
16.11
14.50
0.98
6.44
5.96
1.25
7.28
7.01
-0.07
26
19.54
12.61
7.14
19.34
20.34
-0.94
12.82
13.34
-0.72
7.36
8.24
-0.99
Av
erage
1.91
1.09
1.20
Table 36 — Nitrogen Fixation
Hanford Fine Sandy Loam
Milligrams
N fixed per gram
of mannite
A
A
B
C
A
Sample
r
Cultures
Checks
average
Increase
over
checks
r
Cultures
Checks
average
^
Increase
over
checks
r
Cultures
Checks
average
Increase
over
checks
14
71.52
41.61
31.10
63.05
59.61
7.67
41.69
41.01
0.64
30.19
29.07
1.57
15
38.18
22.07
12.40
29.56
26.55
7.32
21.09
20.12
1.46
14.08
13.87
-0.63
16
30.33
16.46
9.67
32.92
27.84
3.78
16.04
14.85
1.40
8.97
10.61
-1.29
19
25.56
14.43
11.77
26.41
22.49
4.49
13.59
12.29
1.72
12.33
11.80
-0.25
20
38.04
22.84
17.09
38.11
29.66
8.41
23.61
16.39
6.83
20.60
11.52
7.32
22
35.59
22.20
17.30
31.80
29.17
4.52
23.40
17.23
5.57
16.46
11.87
5.0T
23
38.95
19.19
11.90
43.57
36.10
5.16
20.25
14.57
5.15
11.98
8.90
3.04
24
28.79
19.89
18.52
34.61
25.67
6.03
21.52
16.95
3.75
17.51
13.91
4.11
25
26.55
17.86
15.55
26.41
22.70
3.78
17.93
15.51
2.38
13.87
11.31
3.41
Average
5.69
3.21
2.27
424
University of California Publications in Agricultural Sciences [Vol.3
NITRIPICATION29
The most noticeable thing about the nitrification results is the
very wide range of variation in the various representatives of the
Hanford fine sandy loam as compared with the quite uniform and
consistent results obtained with the other types.
Diablo clay adobe. — The percentage of nitrogen nitrified (table
37, 38, and fig. 23) is uniformly low. The B samples showed a less
vigorous nitrifying flora (except in the case of no. 6) than the sur-
face ones. Dried blood in the quantities used seems to depress the
A S. N.+ Cottonseed Meal
-A S. N.+ (NH 4 ) 2 S04
A S. N. + Dried Blood
A Soil Nitrogen
12 5 6 Soils
Percentages of N. Nitrified
Fig. 23. Graph showing the percentages of nitrogen in various nitrogen
containing materials nitrified in the four samples of the Diablo clay adobe.
normal activity (A horizon average 0.81%), while the (NH 4 ) 2 S0 4
(A horizon average 3.03%) and the cottonseed meal (A horizon
average 2.91%), as compared with the incubated control tend to in-
crease the percentage of nitrogen nitrified. It should be kept in mind
that an absolute increase in the nitrogen content may accompany a
decrease in the percentage, due to the greatly increased amount of
nitrogen present after the addition of a nitrogenous substance. The
variation of the samples within this type is very moderate as compared
with the San Joaquin and Hanford types.
29 The figures used in the discussion shows the percentages of the nitrogen in
the cultures which were nitrified. There are two tables for the samples of each
type. The percentages of nitrogen nitrified are rearranged in a second table for
greater ease in comparing results.
1919]
Pendleton: A Study of Soil Types
425
Altamont clay loam. — The percentages of nitrogen nitrified (tables
39 and 40, fig. 24) are as a whole lower than in the Diablo soils. A
similar relative effect of the several nitrogenous materials is seen, for
(NH 4 ) 2 S0 4 is first, cottonseed meal, second, the soil's own nitrogen
third, and dried blood fourth in the percentages of nitrates produced.
As in the Diablo soils the variation is not great from soil to soil.
San Joaquin sandy loam. — A wide range of variation (tables 41,
42, and fig. 25), from 1.2% £o 4.5%, is found in the incubated control,
possibly due, in part, to the considerable variations in the physical
nature of the samples. The relative action of the nitrogenous ma-
A S. N.+ (NH 4 ) 2 S04
A S. N. +Cottonseed Meal
A Soil Nitrogen
A S. N. + Dried Blood
4 7 Soils
Percentages of N. Nitrified
Fig. 24. Graph showing the percentages of nitrogen in various nitrogen
containing materials nitrified in the three samples of the Altamont clay loam.
terials in the soils of the San Joaquin samples as compared with that
in the Diablo and Altamont soils is well shown by the following aver-
ages of the A horizon: dried blood had 0.02%. cottonseed meal had
0.33%, and ammonium sulfate had 0.56% of the nitrogen nitrified,
while the incubated control had 2.47% nitrified. The soils are normally
low in nitrogen, and this, together with the poor physical condition,
made an unfavorable medium for any bacterial activity. This applies
especially to horizons B and C.
Han ford fine sandy loam. — This is by far the most inexplicable
set of results in the nitrification studies (tables 43, 44, and fig. 26).
The physical nature of this type is admirably suited for bacteriological
tumbler cultures, the soil being friable, not puddling readily, and
while in the incubator may be kept at the approximately optimum
moisture content with little difficulty. This property is fairly con-
426 University of California Publications in Agricultural Sciences [Vol. 3
stant throughout all the samples (except no. 14) and cannot well
be supposed to affect the results greatly. No. 14 has a low nitrifying
power throughout, but it is not representative of the type, for it is
heavier in texture than the rest. Moreover, it had been submerged
by river overflows shortly before the collection of the sample. One
would expect these factors to influence the numbers and the activity
of the bacterial flora. There is but little similarity in the way the
different samples of the A or B horizons behave toward any given
/
-— _
\
/
/
\
\
/
\
/
/
\
/
/
\
\
/
/
\
^
v^
\
""•N
'^^"
A. Soil Nitrogen
A. S. N.+ (NHO2SO4
S. N. -{-Cottonseed Meal
10
12
21
26 Soils
13 17 18
Percentages of N. Nitrified
Fig. 25. Graph showing the percentages of nitrogen in various nitrogen
containing materials nitrified in the eight samples of the San Joaquin sandy
loam.
nitrogen containing material. Variations from 1% to 50%, from
0% to 14%, from 4.5% to 8%, or from 15% to 15.5% from soil to
soil, without regularity, give slight basis for generalizations. The
average effect of the A horizon samples of the Hanford fine sandy
loam as regards the several nitrogenous materials is as follows : dried
blood, 5.62%; cottonseed meal, 13.72%; ammonium sulfate, 3.29%;
incubated control, 1.55%. In a general way there is a similarity
between the effects of a given nitrogen containing material on the
surface sample, and on the B horizon. This should be so, since these
soils are very deep and uniform in texture. However, in the C
horizon there were still greater decreases in the bacterial activity.
1919]
Pendleton: A Study of Soil Types
427
As regards nitrification in general there is difficulty in showing
any greater resemblance between the samples of a type than there is
from type to type. In certain features, however, the types are some-
what distinct : ( 1 ) The relation of the nitrification of the soil 's own
nitrogen to the soil's action upon added nitrogen is rather distinct
for the types. The normal soil in the San Joaquin type gave a much
larger per cent of nitrogen than did the soil plus the added nitrogen
containing materials. In the Diablo type (fig. 25) the normal soil
was about midway in its production as compared with the soils to
which the nitrogenous materials were added. In the Hanford fine
sandy loam the normal soils gave a much lower percentage nitrifica-
tion than in the greater number of instances where the soils were
treated with nitrogenous materials. (2) The relative nitrification of
the various nitrogenous materials is somewhat distinct for the types.
The Diablo, Altamont, and San Joaquin show the ammonium sulfate
first, with the cottonseed meal second, and the dried blood third. The
Hanford type shows cottonseed meal first, with dried blood second and
ammonium sulfate third.
Table 37 — Nitrification
Diablo Clay Adobe
Soil nitrogen
a
Soil nitrogen and
ammonium sulfate
A
Soil nitrogen :
dried blood
A
and
Soil nitrogen and
cottonseed meal
A
Sample
6 si
11
o
w .
a. bfl
'as
_, o
Eh
>
si
6 si
®tJ
« s
u $
0)
<k si
_ o
n <°
o.S
s>d£
O li
o si
to •
a> Suo
o.S
6H
O U
o si
<Dntf
If
a> si
£•1
« w
o.S
za
g' 5
1-A
0.90
104.43
0.86
5.35
146.82
3.65
2.20
347.22
0.63
5.00
198.42
2.50
1-B
0.28
93.34
0.30
0.77
135.74
0.57
Tr.
336.14
Tr.
187.34
1-C
0.19
57.22
0.33
0.25
99.62
0.25
0.07
300.02
0.02
0.16
151.22
2-A
0.47
91.76
0.51
3.47
134.16
2.58
4.07
334.56
1.22
6.82
185.76
3.77
2-B
0.33
67.60
0.49
1.17
110.00
1.06
0.08
310.40
0.19
161.60
0.12
2-C
0.59
59.54
0.29
101.94
0.80
302.34
0.80
153.54
5-A
0.47
83.82
0.56
3.81
126.22
3.02
1.66
326.62
0.51
3.76
177.82
2.12
5-B
0.36
64.78
0.56
0.42
107.18
0.39
0.19
307.58
0.06
0.97
158.78
0.61
6-A 0.59 116.58 0.51
6-B 1.65 101.54 1.63
6-C 0.96 78.10 1.23
4.58 158.98 2.88
3.00 143.94 2.08
1.01 120.50 0.84
3.13 359.38 0.87
1.19 344.34 0.35
0.37 320.90 0.01
6.88 210.58 3.26
4.55 195.54 2.32
0.47 172.10 0.27
I
428
University of California Publications in Agricultural Sciences [Vol. 3
55
oil
1
\
4o
\
\
40
\
\
35
\
1
o! )
\
1
J.J
\
1
20
\
1
1.)
\
1
!
\
Jo
\
\
s
5
-^
s
/ \
/ \
s
s .
-v
15
L6
23
24
Fig. 26.
containing
loam.
17 20 22
Percentages of N. Nitrified
Graph showing the percentages of nitrogen in various nitrogen
materials nitrified in the nine samples of the Hanford fine sandy
A S. N. + Cottonseed
Meal
^ A S. N.+ (NH 4 ) 2 S04
A Soil Nitrogen
A S. N. + Dried Blood
25 Soils
1919]
Pendleton: A Study of Soil Types
429
Sample
1
2
5
6
Average
A
0.86
0.51
0.56
0.51
0.61
Table 38 — Nitrification — Percentages of Nitrogen Nitrified
Diablo Clay Adobe
Soil nitrogen and Soil nitrogen Soil nitrogen
Soil nitrogen ammonium sulfate and dried blood cottonseed meal
— * , , a * , a ; , a *
BC ABC ABC ABC
0.30 0.33 3.65 0.57 0.25 0.63 0.02 2.50
0.49 2.58 1.06 1.22 3.77 0.12
0.56 3.02 0.39 0.51 0.06 2.12 0.61
1.63 1.23 2.88 2.08 0.84 0.87 0.35 0.01 3.26 2.32 0.27
0.74 0.52 3.03 1.02 0.36 0.81 0.10 0.01 2.91 0.76 0.09
Table 39 — Nitrification
Altamont Clay Loam
So
il nitrogei
A
i
Soil nitrogen and
ammonium sulfate
Soil nitrogen and
dried blood
A
Soil nitrogen and
cottonseed meal
A
6 &i
CO •
eg
u S
CD
a> be
6 tx
CD
CD fafi
6 tx
CD
tffl
0- fcJD
$
J--T3
Sample
If
_ O
^3 cc
o h
®T3
_ o
O U
1*
Is
_ o
Is M
o.S
Eh
o u
IS
^_ o
• ©.a
3-A
0.60
123.42
0.49
4.12
165.82
2.49
1.17
366.22
0.32
3.57
217.42
1.64
3-B
0.04
87.56
0.05
0.39
129.96
0.32
0.18
330.36
0.03
181.56
3-C
0.27
67.52
0.40
0.20
109.92
0.18
0.10
310.32
0.10
161.52
4-A
1.30
102.58
1.27
2.95
144.98
2.05
2.34
345.38
0.68
4.83
196.58
2.46
4-B
0.45
52.96
0.85
95.36
0.10
295.76
146.96
4-C
40.96
83.36
283.76
0.20
134.96
0.15
7-A
0.50
104.24
0.48
1.35
146.64
0.93
0.40
347.04
0.12
1.27
198.24
0.64
7-B
0.25
73.20
0.34
0.32
115.60
0.28
316.00
167.20
7-C
59.88
102.28
302.68
153.88
Table 40 — Nitrification — Percentages of Nitrogen Nitrified
Altamont Clay Loam
Soil nitrogen
ABC
Soil nitrogen and
ammonium sulfate
A
Soil
and d:
nitrogen
ried blood
Soil nitrogen and
cottonseed meal
A
Sample
A
B
^
c
A
B C
A B
C
3
0.49
0.05
0.40
2.49
0.32
0.18
0.32
1.64
4
1.27
0.85
2.05
0.68
2.46
0.15
7
0.48
0.34
0.93
0.28
0.12
0.64
Average
0.75
0.41
0.13
1.82
0.20
0.06
0.37
1.58
0.05
430
University of California Publications in Agricultural Sciences [Vol. 3
Table 41 — Nitrification
San Joaquin Sandy Loam
Soil nitrogen
Soil nitrogen and
ammonium sulfate
Soil
nitrogen and
Iried blood
Soil nitrogen and
cottonseed meal
A
Sample
10- A
O bi
0.52
a3
a> bi
&a
_ o
n *
Eh
37.46
o u
u *>
1.4
o si
s a
0.24
03 •
a> bSt
'aa
|.a
122.26
%8
y
p U
0.2
6 si
is
0.06
Xfl •
<a he
'as
©.a
En
302.46
Sol
O U
I"
0.02
6 m
^a
£%
0.10
<v bt
£a
_ o
|.S
121.46
y
p ^
I*
0.08
10-B
0.23
27.18
0.9
0.08
111.98
0.07
292.18
111.18
10-C
0.07
20.66
0.3
0.06
105.46
0.06
285.66
0.08
104.66
0.08
11-A
1.25
50.30
2.5
0.50
135.10
0.4
0.27
315.30
0.09
0.95
134.30
0.7
11-B
41.56
0.02
126.36
0.08
306.56
0.03
0.02
125.56
11-C
0.14
38.86
0.4
Tr.
123.66
Tr.
303.86
Tr.
122.86
12- A
0.80
46.52
1.7
0.55
131.32
0.4
0.09
311.52
0.03
2.05
130.52
1.6
12-B
0.18
33.12
0.5
0.11
117.92
0.09
Tr.
298.12
Tr.
117.12
12-C
0.14
40.82
0.3
0.06
125.62
0.06
305.82
0.06
124.82
13-A
0.49
40.00
1.2
0.59
124.80
0.5
0.07
305.00
0.02
0.10
124.00
0.08
13-B
0.06
40.41
0.10
125.21
0.08
0.21
305.41
0.69
124.41
13-C
0.35
32.70
1.1
0.25
117.50
0.2
0.00
297.70
0.96
116.70
17-A
0.54
28.92
1.9
0.45
113.72
0.4
Tr.
293.92
112.92
17-B
18.42
103.22
Tr.
283.42
0.08
102.42
0.08
18- A
1.25
27.46
4.5
1.00
112.26
0.9
292.46
Tr.
111.46
18-B
Tr.
16.18
Tr.
100.98
Tr.
281.18
Tr.
100.18
18-C
19.48
0.10
104.28
1.0
284.48
103.48
21-A
1.25
29.00
4.3
1.30
113.80
1.1
Tr.
294.00
0.13
113.00
21-B
11.92
96.72
276.92
95.92
21-C
0.01
14.02
0.01
98.82
0.01
0.15
279.02
0.15
98.02
26-A
0.95
40.68
2.3
0.80
125.48
0.6
Tr.
305.68
0.19
124.68
0.10
26-B
Tr.
26.28
111.48
Tr.
291.68
Tr.
110.68
26-C
16.48
101.28
Tr.
281.48
100.48
Table 42 — Nitrification — Percentages of Nitrogen Nitrified
San Joaquin Sandy Loam
Soil
nitrogen
Soil nitrogen and
ammonium sulfate
Soil nitrogen
and dried blood
A
Soil nitrogen and
cottonseed meal
Sample
r
A
B
c N
' A
B
c '
r
A
B C
A
B
c'
10
1.4
0.9
0.3
0.2
0.07
0.06
0.02
0.08
0.08
11
2.5
0.4
0.4
0.09
0.03
0.7
12
1.7
0.5
0.3
0.4
0.09
0.03
1.6
13
1.2
1.1
0.5
0.08
0.20
0.02
0.08
17
1.9
0.4
0.08
18
4.5
0.9
1.00
21
4.3
1.1
0.01
0.10
26
2.3
0.6
0.1
Average
2.47
0.17
0.3
0.56
0.03
0.18
0.02
0.33
0.01
0.01
1919]
Pendleton: A Study of Soil Types
431
Table 43 — Nitrification
Eanford Fine Sandy Loam
Soil nitrogen
Soil nitrogen and
ammonium sulfate
A
Soil nitrogen and
dried blood
A
Soil nitrogen and
cottonseed meal
r -
o &i
c
ce .
O bE
O bi
c
CO .
as
o bi
^ a
$ bi)
t —
O M
w
<U bJD
fl'g
|§
Sample 2
_ o
o.S
&S
O S-,
©T3
o.S
Eh
"S ©
£3
o.S
Eh
I 5
OT3
11
1*
o.S
Eh
O U
14-A 0.20
119.22
0.25
161.62
0.1
10.35
254.22
4.1
1.85
166.22
i.i
14-B 0.45
82.02
0.42
124.42
0.23
217.02
0.48
129.02
14-C 0.07
58.14
0.1
0.75
100.54
0.7
0.15
193.14
0.1
0.10
105.14
0.1
15- A 1.45
53.10
2.7
3.20
95.50
. 3.4
0.40
188.10
0.2
50.85
100.10
50.8
15-B 0.18
40.24
0.4
0.19
82.64
0.2
Tr.
175.24
1.42
87.24
1.6
15-C 0.03
27.74
0.1
0.01
70.14
Tr.
162.74
0.03
74.74
16-A 0.87
55.68
1.6
2.50
98.08
2.5
0.50
190.68
0.2
4.60
102.68
4.5
16-B 0.11
29.70
0.4
0.08
72.10
0.1
Tr.
164.70
3.70
76.70
4.8
16-C 0.03
21.22
0.1
Tr.
63.62
0.05
156.22
0.17
68.22
0.2
19-A 1.00
44.98
2.2
2.03
87.38
2.3
0.21
179.98
0.1
7.48
91.98
8.1
19-B 0.08
24.58
0.3
0.12
66.98
0.2
159.58
0.20
71.58
0.3
19-C 0.16
23.60
0.7
0.15
66.00
0.2
Tr.
158.60
0.20
70.60
0.3
20-A 0.77
59.32
1.3
1.24
101.72
1.2
27.39
194.32
14.1
6.19
104.32
5.9
20-B 0.12
32.78
0.4
0.11
75.18
0.1
15.50
167.78
9.2
1.45
77.78
1.9
20-C
23.04
65.44
158.04
0.07
68.04
0.1
22-A 0.83
58.34
1.4
6.48
100.74
6.4
2.68
193.34
1.4
13.58
103.34
13.1
22-B 0.27
34.46
0.8
0.26
76.86
0.3
0.04
169.46
0.02
1.91
79.46
2.4
22-C 0.85
23.74
3.6
5.40
66.14
8.2
0.52
158.74
0.3
2.50
68.74
3.6
23-A 1.45
72.20
2.0
8.95
114.6
7.8
37.25
207.20
17.9
18.25
117.20
15.5
23-B 0.75
29.14
2.6
8.90
71.54
12.5
0.47
164.14
0.3
2.65
74.14
3.6
23-C 0.32
17.80
1.8
12.40
60.20
20.6
0.02
152.80
0.01
1.30
62.80
2.1
24-A 0.80
51.34
1.6
4.10
93.74
4.4
22.35
186.34
11.9
14.35
96.34
14.9
24-B 0.03
33.90
0.1
0.36
76.30
0.5
0.46
168.90
0.3
5.91
78.90
7.5
24-C 0.33
27.82
1.1
0.33
70.22
0.5
0.63
162.82
0.4
0.73
72.82
1.0
2 5- A 0.56
45.40
1.2
1.30
87.80
1.5
1.30
180.40
0.7
8.65
90.40
9.6
25-B 0.32
31.01
1.0
0.32
73.41
0.4
Tr.
166.01
0.05
76.01
0.06
25-C 0.11
22.62
0.5
0.16
65.02
0.2
Tr.
157.62
Tr.
67.62
Table 44 — Nitrification — Percentages of Nitrogen Nitrified
Hanford Fine Sandy Loam
Soil nitrogen
Soil nitrogen and
ammonium sulfate
Soil nitrogen
and dried blood
Soil nitrogen and
cottonseed meal
Sample
A
B
C
f
A
B
C *
' A
B
c N
r "
A
B
C
14
0.1
0.1
0.7
4.1
0.1
1.1
0.1
15
2.7
0.4
0.1
3.4
0.2
0.2
4.5
4.8
0.2
16
1.6
0.4
0.1
2.5
0.1
0.2
4.5
4.8
0.2
19
2.2
0.3
0.7
2.3
0.2
0.2
0.1
8.1
0.3
0.3
20
1.3
0.4
1.2
0.1
14.1
9.2
5.9
1.9
0.1
22
1.4
0.8
3.6
6.4
0.3
8.2
1.4
0.02
0.3
13.1
2.4
3.6
23
2.0
2.6
1.8
7.8
12.5
20.6
17.9
0.3
0.01
15.5
3.6
2.1
24
1.6
0.1
1.1
4.4
0.5
0.5
11.9
0.3
0.4
14.9
7.5
1.0
25
1.2
1.0
0.5
1.5
0.4
0.2
0.7
9.6
0.06
Average
1.55
0.66
0.88
3.29
1.59
3.38
5.62
1.09
0.09
13.72
2.55
0.82
432 University of California Publications in Agricultural Sciences [Vol.3
Greenhouse Data
There are objections to all greenhouse work due to somewhat un-
natural conditions for the usual indicator crops, the lack of a normal
water supply, the small amount of root space, etc. Crowding of the
pots is also apt to cause variations. Even the slight change in the loca-
tion of a pot on the bench will affect the growth of plants, as some of
the elaborate precautions for moving the pots daily, and in a given
order, testify. The outstanding advantage of greenhouse work is that
with a given indicator crop a group of soils, or soil conditions, may be
compared under very similar conditions.
In the present case, the leaks in the sash allowed rain water to fall
into some of the pots to a considerable extent. The pots so affected
showed a poorer growth in the cases of the heavy Altamont and
Diablo samples, where the soil was readily compacted, while in the
poor Hanford and San Joaquin soils the pots receiving leakage water
showed markedly better growth.
To minimize such errors, as much as possible, triplicates were
used, as above explained, besides repeating the series. In working
out the final averages of the crop it was suggested that a selection be
made of the crop dry weights, in case that there was a marked varia-
tion between the triplicates, using the two weights close together, and
excluding the third if it were widely divergent. However, when one
begins to select certain figures from a series, and bases comparisons
upon these alone, there is apt to be the tendency to select those figures
that will prove the point in question, unless there is some known dis-
turbing factor causing the divergence and which warrants the exclu-
sion of certain figures.
Other cases that are rather hard to deal with are those in which
the number of plants reaching maturity was not up to the standard to
which the series was thinned when the plants were young. This fail-
ure may have been due to poor germination, or to accidental destruc-
tion of the plants during growth. Sometimes less than the standard
number of plants will give a much greater dry weight per plant than
the normal number. It was not deemed advisable to use the weight
per plant, but rather to use the total dry weight of the crop, and only
consider of value the series in which the number of plants per pot
was practically constant.
In the greenhouse work the Diablo clay adobe, the Altamont clay
loam, and the Hanford fine sandy loam samples were compared by
1919]
Pendleton: A Study of Soil Types
433
two croppings, while one crop was grown on the San Joaquin sandy
loam soils. The infertility of the San Joaquin soils, in some cases
extreme, greatly retarded crop growth.
Diablo clay adobe. First crop. — Due to the presence of wild oat
seed in all the four samples of this soil, and the inability to distin-
guish the young wild oat plants from the planted oats, wheat, or
barley when thinning, the value of the results of the grain crops in
this series is much decreased. The averages plotted include the total
Z5
20
*\5
a
u
10
Oats
and
Bur Clover
Bur Clover
as col us
Soils
Fig. 27. Graph showing the total dry matter produced by wheat, barley,
oats, Phaseolus, bur clover, and oats and bur clover on the four samples of
Diablo clay adobe. First crop.
crop, whether pure or with a greater or less quantity of the wild oats,
though the number of plants harvested was usually six or less.
Planting the oats and bur clover together was not a success. In three
of the soils the crop of bur clover alone was greater than that of the
six bur clover plants plus the six oat plants. Plate 44 shows how, in
some cases, the oats dominated, and in others the bur clover was
superior. On the soils of this type bur clover was the most satisfactory
crop, while the white beans were the most unsatisfactory of all.
Comparing the total crops (see fig. 27 and tables 45-50), it will
be seen that 1, 5, 2, 6 is the order for bur clover, soil no. 1 giving the
4
434
University of California Publications in Agricultural Sciences [Vol. 3
best crop and soil no. 6 the poorest, while nos. 5, 1, 2, 6 is the order
for barley and wheat. Oats show nearly double the crop on soil 5
that it does on any of the other three soils. There is thus a general
agreement between the indicators that the soils are not of the same
productivity.
Table 45 — Diablo Clay Adobe, First Crop
Wheat
Planted, November 6, 1915. Harvested, July 10, 1916
Straw Grain Total dry matter
, A . A „ , A .
r \ f \ r \
No. Average Average Average
Pot plants Weight weight Weight weight Weight weight
1-1 Wheat 2 3.65 0.25
Oats 4 2.15 0.69 6.74
1-2 Wheat
Oats 6 4.05 2.47 6.51
1-3 Wheat 1 1.83
Oats 5 5.20 5.62 1.64 1.68 8.66 7.30
2-1 Wheat 5 5.33 0.05
Oats 1 0.43 i 5.81
2-2 Wheat 4 3.53 0.03
Oats 2 0.69 0.04 4.31
2-3 Wheat 3 2.55
Oats 3 1.39 4.63 0.49 0.21 4.43 0.84
Notes
5-1
Wheat 2
4.33
Oats 4
1.56
5-2
Wheat 3
7.28
Oats 2
3.23
5-3
Wheat 3
7.09
Oats 2
0.64
6-1
Wheat 2
2.19
Oats 4
1.03
6-2
Wheat
Oats 5
1.72
6-3
Wheat 2
2.31
Oats 4
2.51
8.04
0.90
0.42
1.81
1.02
0.48
0.47
7.21
13.44
1.70 8.68 9.74
3.22
1.72
3.25 0.70 0.17 5.53 3.49
1919]
Pendleton: A Study of Soil Types
435
Table 46 — Diablo Clay Adobe, First Crop
Barley
Planted, November 6, 1915. Harvested, April 28, 1916
Straw Grain Total dry matter
Pot
No.
plants
r
Weight
Average
weight
r
Weight
Average
weight
r
Weight
Average
weight
1-1
6
5.19
1.06
6.25
1-2
Barley 5
Oats 1
4.79
0.75
5.54
1-3
Barley 4
5.75
1.34
Oats 2
5.24
0.98
1.38
8.07
6.62
2-1
6
5.12
1.05
6.17
2-2
6
4.87
1.71
6.58
2-3
Barley 5
2.78
0.49
Oats 1
0.69
4.49
0.23
1.16
4.19
5.65
5-1
6
6.59
2.12
8.70
5-2
Barley 5
3.01
Oats 1
2.56
0.25
3.25
5-3
Barley 5
3.01
Oats 1
8.43
5.86
0.04
1.95
11.48
7.81
6-1
6
4.62
1.26
5.88
6-2
6
4.36
1.25
5.61
6-3
Barley 5
0.33
Oats 1
3.49
4.16
0.24
1.02
4.06
5.18
Notes
Table 47 — Diablo Clay Adobe, First Crop
Oats
Planted, November 6, 1915. Harvested, May 8, 1916
Straw Grain Total dry matter
Pot
No.
plants
r
Weight
Average
weight
r
Weight
Average
weight
r
Weight
Average
weight
1-1
6
4.11
1.24
5.35
1-2
6
6.56
2.59
9.15
1-3
6
4.76
5.14
1.34
1.72
6.10
6.86
2-1
6
4.36
1.10
5.46
2-2
6
total
only
total i
only
6.92
2-3
6
6.66
5.51
2.06
1.58
8.72
7.03
5-1
7
7.55
2.59
10.15
5-2
6
10.66
4.38
15.04
5-3
6
10.10
3.12
13.22
6-1
6
4.70
1.48
6.18
6-2
6
6.81
1.42
8.22
6-3
6
6.78
1.09
7.88
Notes
One barley plant
436 University of California Publications in Agricultural Sciences [Vol. 3
Table 48 — Diablo Clay Adobe, First Crop
Bur Clover
Planted, November 6, 1915. Harvested, May 8, 1916
No.
plants
St
raw
Gi
rain
Total dr
r
Weight
y matter
Pot
f
Weight
Average
weight
r
Weight
Average
weight
Average
weight
1-1
5
11.01
15.13
26.32
1-2
4
9.07
14.15
23.22
1-3
6
12.18
10.75
13.02
14.16
25.20
24.91
2-1
6
8.26
9.89
18.16
2-2
5
7.45
8.93
16.39
2-3
6
7.97
7.89
8.02
8.98
15.99
16.84
5-1
7
11.14
12.33
23.48
5-2
8
10.67
13.05
23.72
5-3
7
10.55
10.79
9.76
11.71
20.31
22.50
6-1
6
7.96
8.73
16.69
6-2
6
8.26
9.76
18.02
6-3
6
6.87
7.69
6.04
8.18
12.91
15.87
Table 49—
Diablo Clay Adobe, First Crop
Notes
Oats and Bur Clover
Planted, November 6, 1915. Harvested, May 8, 1916
No.
plants
St
raw
Grain
Total di
Weight
•y matter
Pot
r
Weight
Average
weight
r
Weight
Average
weight
Average
weight
1-1
Clover 3
10.37
11.93
22.30
Oats 6
2.38
0.14
2.52
1-2
Clover 6
8.19
9.28
17.47
Oats 6
3.48
0.70
4.16
1-3
Clover 6
13.53
9.81
23.34
Oats 6
2.65
13.53
0.27
10.71
2.92
24.24
2-1
Clover 6
2.13
2.57
4.70
Oats 6
5.77
1.81
7.58
2-2
Clover 6
4.24
4.62
8.87
Oats 6
4.56
1.26
5.82
2-3
Clover 6
3.43
4.51
7.94
Oats 6
3.20
7.75
0.46
5.08
3.66
12.85
5-1
Clover 6
10.88
9.78
20.66
Oats 6
2.45
0.27
2.71
5-2
Clover 5
10.52
9.32
19.84
Oats 6
2.19
0.51
2.79
5-3
Clover 5
8.31
8.36
16.66
Oats 6
3.45
12.60
0.66
9.63
4.10
22.26
6-1
Clover 6
8.90
9.56
18.46
Oats 6
3.10
0.35
3.45
6-2
Clover 6
9.01
5.82
14.83
Oats 6
2.09
0.52
2.61
6-3
Clover 6
6.51
10.45
16.97
Oats 5
2.33
10.65
0.47
9.06
2.80
19.71
Notes
1919] Pendleton: A Study of Soil Types 437
Table 50 — Diablo Clay Adobe, First Crop
Phaseolus vulgaris
Planted, April 4, 1916. Harvested, October 7, 1916
Straw Grain Total dry matter
Notes
Growth poor and
slow through-
Pot
No.
plants
Weight
Average
weight
r
Weight
Average
weight
Weight
Average
weight
1-1
8
2.05
0.58
2.63
i
1-2
1
0.94
0.87
1.81
1-3
12
2.86
1.95
1.37
0.94
4.23
2.89
2-1
3
0.53
0.21
0.74
2-2
10
0.83
0.83
2-3
17
1.26
0.87
0.11
0.10
1.37
0.98
5-1
3
0.53
0.40
0.93
5-2
2
0.46
0.41
0.87
5-3
0.33
0.27
0.60
6-1
2
0.22
0.22
6-2
6-3
1
0.23
0.15
0.23
0.15
Diablo clay adobe. Second crop. — The. crops used in this plant-
ing were milo (two series, one following oats and bur clover, and the
other following oats alone), cowpeas, millet, and soy beans. The
crop was thinned as follows : milo to eight plants, millet to twelve,
soy beans to six, and cowpeas to six. The total dry weight (tables
51-55) of the largest leguminous crop in this planting is about one-
third of that of the bur clover in the first planting ; though the grains
are proportionately not nearly so much less than in the first crop.
Soil no. 2 has the least pronounced adobe structure, but was the most
easily puddled. The plants in one of the pots of soy beans of soil
no. 2 were entirely killed by too much water.
Comparing the relative growth on the soils, the notes made while
the crops were growing coincide very closely with the dry weights.
As to the relative crop production (fig. 28), it can be said that soils
nos. 1 and 5 produced larger crops than soils nos. 2 and 6. Thus the
second crop results substantiate those of the first crop.
438
University of California Publications in Agricultural Sciences [Vol. 3
So.y Beans
j-Milo B
•~*"f' ! ~.? M <r'Cow Peas
Millet
5 6
Soils
Pig. 28. Graph showing the total dry matter produced by milo (two
series), millet, soy beans, and cowpeas on the four samples of Diablo clay
adobe. Second crop.
Wheat
Oats + Bur CI over
Barley
Oats
Bur Clover
Phaseolas
Fig. 29. Graph showing the' total dry matter produced by wheat, barley,
oats, bur clover, Phaseolus, and oats and bur clover on the three samples of
Altamont clay loam. First crop.
Soy Beans B
5qy Beans A
Cow Peas A
Cow Peas B
Milo A
M.loB
Fig. 30. Graph showing the total dry matter produced by milo (two series),
cowpeas (two series), and soy beans (two series) on the three samples of
Altamont clay loam. Second crop.
1919]
Pendleton: A Study of Soil Types
439
Pot
No.
plants
1-1
8
1-2
8
1-3
7
2-1
8
2-2
8
2-3
8
5-1
8
5-2
6
5-3
7
6-1
9
6-2
8
6-3
8
Table 51 — Diablo Clay Adobe, Second Crop
Milo A (following oats)
Planted, June 3, 1916. Harvested, November 16, 1916
Straw Grain Total dry matter
A . A . . A .
r \ r \ r \
Average Average Average
Weight weight Weight weight Weight weight Notes
4.87 4.87 Excluded from
10.00 10.00 average
4.50 4.68 4.50 4.68
2.59 2.59
3.73 3.73
2.92 3.08 2.92 3.08
4.03 4.03
5.13 5.13
8.44 8.44
3.49 3.49
3.08 3.08
2.98 3.18 2.98 3.18
Pot
No.
plants
1-1
8
1-2
8
1-3
8
2-1
8
2-2
8
2-3
8
5-1
8
5-2
8
5-3
8
6-1
8
6-2
8
6-3
8
Table 52 — Diablo Clay Adobe, Second Crop
Milo B (following oats and bur clover)
Planted, June 3, 1916. Harvested, November 16, 1916
Straw Grain Total dry matter
. A „ . A „ , A „
r \ ( \ r \
Average Average Average
Weight weight Weight weight Weight weight
6.41 . 6.41
8.78 8.78
6.21 7.14 6.21 7.14
3.92 3.92
4.52 4.52
3.63 4.02 3.63 4.02
10.34 10.34
6.17 6.17
5.20 7.24 5.20 7.24
9.29 9.29
3.70 3.70
4.09 5.69 4.09 5.69
Notes
440 University of California Publications in Agricultural Sciences [Vol. 3
Table 53 — Diablo Clay Adobe, Second Crop
Millet (following bur clover)
Planted, June 3, 1916. Harvested, October 6, 1917
Notes
No.
plants
Straw
Gi
rain
Total dry
r
Weight
matter
Pot
r '
Weight
Average
weight
r
Weight
Average
weight
Average
weight
1-1
12
1.52
1.44
2.96
1-2
11
1.34
0.90
2.24
1-3
11
2.03
1.63
1.15
1.16
3.18
2.79
2-1
12
1.26
1.29
2.55
2-2
11
1.49
1.32
2.80
2-3
12
0.93
1.23
0.88
1.16
1.80
2.39
5-1
10
2.26
2.19
4.45
5-2
12
3.35
3.36
6.71
5-3
12
2.02
2.54
1.51
2.35
3.53
4.90
6-1
11
1.19
0.99
2.18
6-2
12
1.59
1.23
2.82
6-3
13
1.26
1.35
1.04
1.09
2.29
2.43
Table 54 — Diablo Clay Adobe, Second Crop
Cowpeas (following wheat)
Planted, August 10, 1916. Harvested, November 16, 1916
Straw Grain Total dry matter
, A . . A „ A
f \ i ^ r \
No. Average Average Average
Pot plants Weight weight Weight weight Weight weight Notes
1-1 7 2.66 2.66
1-2 7 5.30 5.30
1-3 7 3.73 3.89 3.73 3.89
2-1 6 2.57 2.57
2-2 6 4.24 4.24
2-3 6 2.86 3.22 2.86 3.22
5-1 6 2.74 2.74
5-2 6 4.30 4.30
5-3 6 3.64 3.56 3.64 3.56
6-1 6 3.28 3.28
6-2 7 4.10 4.10
6-3 6 3.41 3.60 3.41 3.60
1919]
Pendleton : A Study of Soil Types
441
Table 55 — Diablo Clay Adobe, Second Crop
Soy Beans (following barley)
Planted, June 6, 1916. Harvested, November 14, 1916
No.
plants
Straw
A
Gi
rain
A
Total dry matter
A
f \
Average
Weight weight
Pot
r
Weight
>
Average
weight
r
Weight
Average
weight
Notes
1-1
6
8.48
0.29
8.77
1-2
6
8.58
0.06
8.64
1-3
6
6.87
7.98
0.41
0.25
7.28
8.23
2-1
6
2.12
2.12
Excluded from
2-2
4
3.62
0.40
4.02
average
2-3
5
6.07
4.84
0.38
0.39
6.45
5.23
5-1
6
5.84
0.16
6.00
5-2
6
7.96
0.64
8.60
5-3
6
6.47
6.76
0.69
0.49
7.16
7.25
6-1
6
7.61
0.24
7.85
6-2
6
7.99
0.45
8.43
6-3
6
7.26
7.62
0.17
0.28
7.43
7.90
Altamont clay loam. First crop. — The crops planted in this soil
were wheat, barley, oats, bur clover, Phaseolus, and oats and bur
clover together. The standard number to which the plants were
thinned was six, except in the oats and bur clover series, where three
plants of each were allowed to remain.
With regard to the comparative crop producing power of these
soils under these conditions, soil no. 4 is the best, with soil no. 3 as
the second, and soil no. 7 was the poorest (tables 56-60, fig. 29). The
dry weight data decidedly corroborate the impression given by the
greenhouse appearance of the crops. However, as all the crops were
so small on all the series, the figures do not show as much as they
might have shown had the growth been more nearly optimum for the
several crops.
Table 56 — Altamont Clay Loam, First Crop
Wheat
Planted, February 25, 1916. Harvested, July 10, 1916
Notes
No.
plants
Straw
A
Grain
A
Total dr
Weight
y matter
A
Pot
Weight
Average
weight
Weight
Average
weight
Average
weight
3-1
6
2.62
1.23
3.85
3-2
6
2.93
1.09
3.92
3-3
6
2.86
2.80
1.04
1.12
3.91
3.92
4-1
6
4.20
1.78
5.97
4-2
6
4.03
1.22
5.25
4-3
6
6.20
4.81
1.13
1.38
7.34
6.19
7-1
6
2.64
1.11
3.76
7-2
6
2.58
0.99
3.64
7-3
6
2.90
2.71
0.71
0.93
3.61
3.64
442
University of California Publications in Agricultural Sciences [Vol. 3
Table 57 — Altamont Clay Loam, First Crop
Barley
Planted, April 4, 1916. Harvested, July 11, 1916
No.
plants
St
raw
Grain
Total dr
r
Weight
y matter
Pot
f
Weight
Average
weight
Weight
Average
weight
Average
weight
3-1
1.10
0.76
1.86
3-2
1.45
1.40
2.85
3-3
1.39
1.31
1.18
1.11
2.57
2.43
4-1
1.99
1.43
3.42
4-2
1.90
1.57
3.47
4-3
2.39
2.09
1.85
1.62
4.25
3.71
7-1
0.98
0.90
1.88
7-3
1.06
1.00
0.59
0.71
1.64
1.71
Notes
Table 58 — Altamont Clay Loam, First Crop
Oats
Planted, February 25, 1916. Harvested July 11, 1916
No.
plants
6
SI
raw
A
Grain
Total dry matter
Pot
3-1
r
Weight
1.36
Average
weight
r
Weight
0.38
Average
weight
Weight
1.74
Average
weight
3-2
6
1.60
0.67
2.27
3-3
6
1.70
1.55
0.47
0.51
2.17
2.06
4-1
6
3.05
1.42
4.47
4-2
4
2.62
1.13
3.76
4-3
4
3.46
3.04
1.81
1.45
5.27
4.50
7-1
6
1.21
0.29
1.51
7-2
6
1.00
0.42
1.42
7-3
6
0.88
1.03
0.35
0.35
1.23
1.38
Notes
Table 58 — Altamont Clay Loam, First Crop
Bur Clover
Planted, February 25, 1916. Harvested, July 8, 1916
No.
plants
6
Straw
A
Gi
*ain
Total dr
r
Weight
2.53
y matter
Pot
3-1
r
Weight
1.50
Average
weight
Weight
1.03
Average
weight
Average
weight
3-2
6
0.88
1.17
2.18
3-3
6
0.63
1.00
1.34
1.18
1.96
2.18
4-1
6
2.48
1.47
3.95
4-2
6
2.57
1.57
4.14
4-3
4
2.50
2.52
1.31
1.45
3.81
3.97
7-1
6
0.47
0.66
1.13
7-2
6
0.53
0.24
0.78
7-3
6
0.37
0.46
0.20
0.36
0.57
0.82
Notes
1919]
Pendleton: A Study of Soil Types
443
Table 59 — Altamont Clay Loam, First Crop
Oats and Bur Clover
Planted,
April 14,
1916.
Harvested, July 8, 191
No.
plants
Straw
A
Grain
A
Total di
height
•y matter
K
Pot
r
Weight
"\ r
Average
weight Weight
> r
Average
weight V\
Average
weight
3-1
B.C.
3
0.98
1.25
2.23
Oats
3
0.77
0.10
0.88
3-2
B.C.
4
0.79
1.17
1.96
Oats
4
0.68
0.22
0.90
3-3
B.C.
4
0.48
0.91
1.38
Oats
4
0.78
1.49
0.30
1.32
1.07
2.81
4-1
B.C.
3
0.67
0.32
0.99
Oats
3
2.42
1.75
4.17
4-2
B.C.
3
0.40
0.62
1.01
Oats
3
2.63
1.38
4.01
4-3
B.C.
3
0.51
0.21
0.72
Oats
3
2.77
3.14
1.09
1.78
3.86
4.92
7-1
B.C.
3
0.20
0.27
0.47
Oats
3
0.86
0.74
1.60
7-2
B.C.
3
0.28
0.22
0.50
Oats
3
1.27
0.95
2.22
7-3
B.C.
4
0.42
0.37
0.74
Oats
2
0.64
1.22
0.44
0.98
1.08
2.20
Notes
Table 60 — Altamont Clay Loam, First Crop
Beans (Phaseolus)
Planted, February 25, 1916. Harvested, July 11, 1916
No.
plants
Straw
A
Grain
Total dr;
Weight
y matter
Pot
Weight
Average
weight
r
Weight
Average
weight
Average
weight
3-1
6
2.82
0.13
2.96
3-2
6
1.24
0.35
1.59
3-3
6
1.32
1.79
0.32
0.27
1.64
2.06
4-1
5
1.71
0.25
1.96
4-2
6
1.41
0.59
2.01
4-2
6
1.81
1.64
0.59
0.48
2.41
2.12
7-1
1
0.11
0.09
0.20
7-2
6
0.53
0.53
7-3
5
0.63
0.43
0.03
0.63
0.46
Notes
Altamont clay loam. Second crop. — A slightly different scheme
was used in the planting of this series, only three crops were used,
i.e., soy beans, cowpeas, and milo. Two sets of pots were planted to
each crop, one of the two sets having previously been planted to a
legume, and the other to a non-legume. The milo was thinned so that
444 University of California Publications in Agricultural Sciences [Vol. 3
one pot of each triplicate set would have 8 plants, the second of the
set 12 plants, and the last 16 plants. It was found that the wide
variation in the number of plants had but little effect upon the dry
weight produced per pot (tables 61-66). The effect was indeed so
slight that the totals were averaged up as usual. Figure 30 shows
distinctly that there was very little variation as regards total produc-
tion among these soils, so little as not to warrant any conclusions as
regards substantiation of, or disagreement with, the first crop. It
will be noticed in the second crop of the Diablo series, as well as in
that of the Altamont series, that the maintenance of the soils under
the same conditions for a year or more seems to bring them quite
rapidly to an average crop producing power.
Table 61 — Altamont Clay Loam, Second Crop
Milo A (following wheat)
Planted, August 10, 1916. Harvested, November 17, 1916
Straw Grain Total dry matter
No. Average Average Average
Pot plants Weight weight Weight weight Weight weight Notes
3-1 8 0.77 0.77
3-2 12 1.01 1.01
3-3 16 0.97 0.92 0.97 0.92
4-1 8 1.22 1.22
4-2 12 2.32 2.32
4-3 16 2.08 1.87 2.08 1.87
7-1 8 0.59 0.59
7-2 12 0.99 1.29
7-3 16 1.29 0.95 1.29 0.95
Table 62 — Altamont Clay Loam, Second Crop
Milo B
Planted, August 10, 1916. Harvested, November 15, 1916
Straw Grain Total dry matter
. A . . A . , A .
t ^ r ^> f \
Average Average Average
Weight weight Weight weight Weight weight Notes
0.82 0.82
1.13 1.13
1.15 1.03 1.15 1.03
1.28 1.28
1.82 1.82
1.45 1.52 1.45 1.52
0.66 0.66
0.96 0.96
0.02 0.85 0.92 0.85
Pot
No.
plants
3-1
8
3-2
12
3-3
16
4-1
8
4-2
12
4-3
16
7-1
8
7-2
12
7-3
10
1919]
Pendleton: A Study of Soil Types
445
Table 63 — Altamont Clay Loam, Second Crop
Cowpeas A (following barley)
Planted, August 10, 1916. Harvested, November 17, 1916
Straw
Pot
No.
plants
r
Weight
Average
weight
3-1
6
3.48
3-2
6
4.50
3-3
6
3.00
3.66
4-1
6
2.44
4-2
6
2.59
4-3
6
3.40
2.81
7-1
6
2.64
7-2
6
1.93
7-3
6
2.15
2.24
Grain
A
Average
Weight weight
Total dry matter
Weight
Average
weight
3.48
4.50
3.00
3.66
2.44
2.59
3.40
2.81
2.64
1.93
2.15
2.24
Notes
Table 64 — Altamont Clay Loam, Second Crop
Cowpeas B (following oats and bur clover)
Planted, August 10, 1916. Harvested, November 14, 1916
Straw Grain Total dry matter
Pot
No.
plants
Weight
Average
weight
Average
Weight weight
r
Weight
Average
weight
3-1
6
4.16
4.16
3-2
6
3.63
3.63
3-2
6
2.77
3.52
2.77
3.52
4-1
6
3.35
3.35
4-2
6
2.70
2.70
4-3
6
1.94
2.66
1.94
2.66
7-1
6
1.51
1.51
7-2
6
2.10
2.10
7-3
6
2.85
2.15
2.85
2.15
Notes
Table 65 — Altamont Clay Loam, Second Crop
Soy Beans A (following oats)
Planted, August 10, 1916. Harvested, November 17, 1916
Straw Grain Total drv matter
, A . A . A .
t "\ t \ t \
No. Average Average Average
Pot plants Weight weight Weight weight Weight weight
3-1 6 4.85 4.85
3-2 6 4.25 4.25
3-3 6 4.50 4.53 4.50 4.53
4-1 6 3.53 3.53
4-2 6 3.59 3.59
4-3 6 4.88 4.00 4.88 4.00
7-1 6 3.42 3.42
7-2 6 3.34 3.34
7-3 6 3.42 3.39 3.42 3.39
Notes
446 University of California Publications in Agricultural Sciences [Vol. 3
Table 66 — Altamont Clay Loam, Second Crop
Soy Beans (following Phaseolus)
Planted, August 10, 1916. Harvested November 17, 1916
Straw Grain Total dry matter
. . A . . A . . A „
r \ f \ r \
No. Average Average Average
Pot plants Weight weight Weight weight Weight weight Notes
3-1 6 5.64 5.64
3-2 6 4.94 4.94
3-3 6 4.84 5.14 4.84 5.14
4-1 6 4.74 4.74
4-2 6 4.64 4.64
4-3 6 4.71 4.70 4.71 4.70
7-1 6 5.25 5.25
7-2 6 3.28 3.28
7-3 6 4.39 4.31 4.39 4.31
Hanford fine sandy loam. First crop. — This soil type, with sam-
ples from nine different localities in California, gave a much wider
range of conditions and made a much more interesting series. The
plants used as indicators in this series were milo (twice), millet, cow-
peas (twice), and soy beans. The milo was thinned to eight plants
per pot, the millet to twelve plants, and the cowpeas and soy beans
to six plants. Set A of cowpeas, and set B of milo were unfavorably
located, so that the results of these sets should be discounted.
It is interesting to note the large differences in the average
weights from soil to soil (tables 67-72, and fig. 31), as compared with
the photographs, in which little variation appears. See especially the
soy bean series. In this series two things are to be noted :
1. Averages on soils nos. 15 and 25 are hardly representative be-
cause in both cases excess moisture, from a leaky roof and too heavy
watering, depressed growth. The tendency to become compact and to
remain wet and cold shown by soil no. 15 aided the milo and depressed
the soy beans.
2. The loose, open texture of soil no. 22 seemingly favored the soy
bean growth, though the other plants did not do as well on this soil
as on most of the others.
1919]
Pendleton: A Study of Soil Types
447
Comparing the more satisfactory grains, milo A and millet, it will
be seen that there is somewhat of a parallelism from soil to soil. The
legumes do not always respond similarly to the grains, as in the Diablo
first crop, yet in the Diablo second crop and the Altamont first and
second crops the response of grain and legume seems quite similar.
Hence, it is not safe in every case to judge as to the relationships
shown by legumes and non-legumes.
SqyB^o/*
Fig. 31
Fig. 31. Graph showing the total dry matter produced by millet, milo (two
series), cowpeas (two series), and soy beans on the nine samples of Hanford
fine sandy loam. First crop.
Considering all the variations, one might say that soil no. 23 was
seemingly among the better soils, and soils nos. 16 and 22 among the
poorer soils. Yet when discussing whether the soils be the same or
similar, according to the criterion of the dry weight, one of the Han-
ford groups will be similar according to one crop, and an overlapping
group similar according to the second crop. It can be said with rea-
sonable certainty that these Hanford soils are not closely similar to
one another.
448
University of California Publications in Agricultural Sciences [Vol. 3
Pot
14-1
14-2
14-3
15-1
15-2
15-3
16-1
16-2
16-3
19-1
19-2
19-3
20-1
20-2
20-3
22-1
22-2
22-3
23-1
23-2
23-3
24-1
24-2
24-3
25-1
25-1
25-2
25-3
No.
plants
Table 67 — Hanford Fine Sandy Loam, First Crop
Milo A
Planted, June 10, 1916. Harvested, November 18, 1916
Straw Grain Total dry matter
„ A A . . A
( \ r \ r \
Average Average Average
Weight weight Weight weight Weight weight Notes
15.34 15.34 Most plants bore
12.50 12.50 no grain; some
10.15 12.66 10.15 12.66 ^ rain was im -
mature at har-
vest. These
cases noted,
but no grain
weighed.
13.14 13.14
14.50 14.50
15.21 14.28 15.21 14.28 Not mature
8.67 8.67
5.86 5.86
4.76 6.43 4.76 6.43
7.65 7.65
14.11 14.11
7.01 7.01
14.10 14.10
10.15 10.15
7.68 10.64 7.68 10.64 Not mature
5.34 5.34
5.88 5.88
5.35 5.52 5.35 5.52
8.90 8.90 Not mature
10.04 10.04 Not mature
8.67 9.20 8.67 9.20
10.82 10.82
9.92 9.92 Not mature
6.01 8.92 6.01 8.92 Not mature
11.26 11.26
11.26 11.26
5.70 5.70
9.33 8.76 9.33 8.76
1919] Pendleton: A Study of Soil Types 449
Table 68 — Hanford Fine Sandy Loam, First Crop
Milo B
Planted, June 10, 1916. Harvested, November 20, 1916
Straw Grain Total dry matter
A A. A
No. Average Average Average
Pot plants Weight weight Weight weight Weight weight Notes
14-., 8 10.75 10.75
14-2 8 10.95 10.95
14-3 8 8.84 10.18 8.84 10.18
15-1 5 5.25 5.25
15-2 4 4.62 4.62
15-3 2 3.92 4.60 3.92 4.60
16-1 7 7.36 7.36
16-2 2 2.18 2.18
16-3 4 2.74 4.09 2.74 4.09
19-1 3 3.73 3.73
19-2 8 4.79 4.79
19-3 8 9.60 6.04 9.60 6.04
20-1 8 8.14 8.14
20-2 8 3.23 3.23
20-3 8 3.22 4.86 3.22 4.86
22-1 6 4.74 4.74
22-2 5 3.01 3.01
22-3 7 3.19 3.64 3.19 3.64
23-1 8 5.68 5.68
23-2 5 7.72 7.72
23-3 8 6.93 6.78 6.93 6.78
24-1 3 3.16 3.16
24-2 6 5.64 5.64
24-3 6 3.26 4.02 3.26 4.02
25-1 4 3.07 3.07
25-2 3 2.34 2.34
25-3 8 4.34 3.25 4.34 3.25
450 University of California Publications in Agricultural Sciences [Vol. 3
Table 69 — Hanford Fine Sandy Loam, First Crop
Millet
Planted, June 10, 1916. Harvested: Nos. 15-25, September 20, 1916; No. 14,
October 6, 1916
No.
plants
Straw
A
Grain
Total dry matter
A
Average
Weight weight
Pot
r
Weight
Average
weight
r
Weight
Average
weight
Notes
14-1
12
3.75
2.90
6.65
14-2
13
4.23
2.95
7.18
14-3
14
3.46
3.81
2.01
2.62
5.47
6.43
15-1
12
3.63
1.02
4.65
15-2
12
4.63
1.31
5.93
15-3
12
3.86
4.04
1.12
1.15
4.98
5.19
16-1
13
1.96
0.74
2.70
16-2
12
3.10
1.81
4.91
16-3
12
1.52
2.19
0.73
1.09
2.25
3.29
19-1
12
1.85
0.73
2.58
Seed immature
19-2
12
1.71
0.76
2.48
Poor. Lack of
19-3
12
2.00
1.85
0.69
0.73
2.69
2.58
drainage?
20-1
12
6.54
2.78
9.32
Possible error in
20-2
20-3
12
12
1.70
6.57
6.55
1.01
2.21
2.50
2.71
8.78
9.05
grain weight.
Original shows
6 grams
22-1
12
2.04
0.65
2.69
22-2
12
2.32
0.68
3.00
22-3
12
4.44
2.93
1.90
1.08
6.34
4.01
23-1
12
6.12
1.21
7.33
23-2
12
6.13
2.14
8.27
23-3
12
6.01
6.08
1.97
1.78
7.99
7.86
24-1
12
4.18
1.50
5.69
24-2
12
2.80
0.91
3.70
24-3
11
4.89
3.96
2.08
1.50
6.98
5.46
25-1
12
2.06
0.77
2.83
25-2
12
2.01
0.51
2.52
25-3
12
4.31
2.79
2.15
1.14
6.46
3.94
1919J
Pendleton: A Study of Soil Types
451
Table 70 — Hanford Fine Sandy Loam, First Crop
Soy Beans
Planted, June 10, 1916. Harvested, December 11, 1916
Straw Beans Total dry matter
f ^ f ^ f A ^
No. Average Average Average
Pot plants Weight weight Weight weight Weight weight Notes
14-1 6 16.69 16.69 Immature seed
14-2 6 16.28 16.28 Immature seed
14-3 6 11.89 14.95 0.44 0.15 12.33 15.10 Immature seed
15-1 6 14.08 0.23 14.31 Immature seed
15-2 6 5.17 5.17 Immature seed
15-3 6 6.53 8.59 0.08 6.53 8.67 Immature seed
16-1 6 12.63 0.32 12.95 Immature seed
16-2 6 14.60 14.60 Immature seed
16-3 6 16.60 14.61 0.11 16.60 14.72 Immature seed
19-1 6 12.84 12.84 Immature seed
19-2 6 11.68 11.68 Immature seed
19-3 6 16.03 13.52 16.03 13.52 Immature seed
20-1 6 8.77 8.77 Immature seed
20-2 6 16.33 16.33 Immature seed
20-3 6 14.27 13.13 14.27 13.13 Immature seed
22-1 6 20.28 20.28 Immature seed
22-2 6 19.44 19.44 Immature seed
22-3 6 15.60 18.44 15.60 18.44 Immature seed
23-1 6 21.42 21.42 No seed
23-2 6 20.75 ...... 20.75 No seed
23-3 6 20.68 20.95 20.68 20.95 Immature seed
24-1 6 17.37 17.37 Immature seed
24-2 6 21.24 21.24 Immature seed
24-3 6 13.70 17.43 13.70 17.43 Immature seed
25-1 6 5.53 . 5.53 Eained on; exclud-
ed from average
25-2 6 17.85 17.85 No seed
25-3 6 21.58 19.71 21.58 19.71 Immature seed
452 University of California Publications in Agricultural Sciences [Vol. 3
Table 71 — Hanford Fine Sandy Loam, First Crop
Cowpeas A
Planted, June 10, 1916. Harvested, October 21, 1916
No.
plants
Straw-
Beans
A
Total d
f
Weight
ry matter
Pot
Average
Weight weight
r ^
Average
Weight weight
Average
weight Notes
14-1
6
2.99
0.93
3.92
14-2
6
3.52
3.52
14-3
6
4.18 3.56
4.18
3.87
15-1
„
15-2
15-3
--
16-1
1
2.98
2.98
Immature seed
16-2
3
3.05
1.50
4.58
16-3
4
2.60 2.88
2.16 1.22
4.76
4.10
19-1
6
1.49
0.27
1.77
19-2
6
1.54
0.28
1.82
19-3
2
1.10 1.38
0.47 0.34
1.57
1.72
20-1
6
2.86
0.32
3.18
20-2
6
2.08
0.58
2.66
20-3
6
2.99 2.64
0.33 0.41
3.32
3.05
22-1
5
1.80
0.23
2.02
22-2
..
22-3
2
1.96 1.88
0.39 0.31
2.35
2.19
23-1
..
23-2
1
1.80
0.76
2.57
23-3
1.80
0.76
2.57
24-1
2
1.06
0.25
1.30
24-2
1
1.80
1.29
3.09
24-3
2
1.75 1.54
0.45 0.66
2.20
2.20
25-1
3
2.74
2.03
4.78
25-2
1
1.88
2.28
4.17
25-3
2
2.12 2.25
1.24 1.85
3.36
4.10
1919] Pendleton: A Study of Soil Types 453
Table 72 — Hanford Fine Sandy Loam, First Crop
Cowpeas B
Planted, June 10, 1916. Harvested, November 21, 1916
Straw Beans Total dry matter
' \ » ' * »' " >
No. Average Average Average
Pot plants Weight weight "Weight weight Weight weight Notes
14-1 6 3.94 3.94
14-2 6 5.93 5.92
14-3 6 3.32 4.39 3.32 4.39
15-1 6 7.24 7.24
15-2 6 5.34 5.34
15-3 6 4.61 5.74 4.61 5.74
16-1 6 5.90 5.90
16-2 6 5.82 5.82
16-3 6 3.65 5.12 3.65 5.12
19-1 6 3.34 3.34
19-2 6 3.38 3.38
19-3 6 3.87 3.53 3.87 3.53 1 died early
20-1 6 3.09 3.09
20-2 6 3.15 3.15 1 died early
20-3 6 2.80 3.01 ..,. 2.80 3.01
22-1 6 3.12 3.12
22-2 6 3.61 3.61
22-3 6 4.92 3.88 4.92 3.88
23-1 6 4.59 4.59
23-2 6 6.04 6.04
23-3 6 4.08 4.90 4.08 4.90
24-1 6 3.81 3.81
24-2 5 4.28 4.28
24-3 6 6.42 4.84 6.42 4.84
25-1 5 4.17 4.17
25-2 6 3.93 3.93 1 died early
25-3 6 4.86 4.32 4.86 4.32
Hanford fine sandy loam. Second crop. — Barley (twice), oats,
wheat, bur clover (Medicago sp.), and Melilotus indica were the indi-
cator crops used when the Hanford soils were planted the second time.
In all cases a sufficient quantity of seed was used to insure the growth
of more plants than would be raised to maturity. Later the plants
in each pot were thinned to six in number, good specimens and well
454 University of California Publications in Agricultural Sciences [Vol. 3
spaced. The final number of plants varied, but was almost always six.
An attempt was made to reduce at least partially the shading and
exposure effects. The pots were periodically changed from position
to position on the bench.
The total dry weights produced on the several soils are interesting
(tables 73-78, and fig. 33). The grains gave more uniform results in
this crop than in the first. Soils nos. 14 and 23 show the best crops,
and they are the ones that have the highest amounts of total nitrogen.
The legumes selected must have been particularly well adapted to the
growing conditions and the soils, because the growth was enormous.
In the amount of dry matter produced the parallelism between the
two legumes from soil to soil is close. It is noteworthy that soil no. 14,
Wheat
Bur Clover
Oats
"^Meli lotus
26 ^ arle ^
Fig.3£
Fig. 32. Graph showing the total dry matter produced by barley, wheat,
oats, rye, bur clover, and Melilotus indica on the eight samples of San Joaquin
sandy loam. First and only crop.
which showed the highest total nitrogen and produced the most dry
matter from the grains, gave the poorest crop of legumes. The notes
taken during the growing period show that the relative appearances
quite early and throughout the period of growth are usually a good
index to the relative amounts of dry matter produced. This is so,
even though the photographs of the mature plants do not show dif-
ferences nearly as great in magnitude as do the dry weights.
This type does not show any marked tendency for the several soils
to approach a more uniform crop producing capacity through being
kept under the same conditions. In fact, the second crop shows
greater variations than the first. And this type does not show that
these nine soils, mapped under a single type name, are closely similar
to one another in crop producing power.
1919] Pendleton: A Study of Soil Types 455
Table 73 — Hanford Fine Sandy Loam, Second Crop
Wheat (following millet)
Planted, October 30, 1916. Harvested, June 21, 1917
Straw Grain Total dry matter
, A . . A „ . A .
r ^ f ~\ f ^
No. Average Average Average
plants Weight weight Weight weight Weight weight Notes
3.55 14.30
2.10 7.30
10.26 6.45 4.03 21.30 14.30
1.30 4.65
1.50 6.35
3.66 1.10 1.30 3.90 4.96
Pot
plants
Weight
14-1
6
10.75
14-2
5
5.20
14-3
6
14.85
15-1
6
3.55
15-2
6
4.85
15-3
6
2.80
16-1
6
3.20
16-2
6
8.20
0.95 4.15
3.70 11.90 Eained on, exclud-
ed from average
16-3 6 2.80 3.00 0.70 0.82 3.50 3.82
0.75
0.65
2.60 0.60 0.66
2.80
1.55
4.75 12.90 2.17
0.90
0.40
4.18 0.90 0.73
1.60
1.60
4.46 1.10 1.43
8.30
0.90
3.20 5.40 0.90
9.05
0.35
2.37 0.80 0.57
19-1
6
2.80
19-2
6
2.80
19-3
6
2.20
20-1
6
5.45
20-2
6
4.05
20-3
6
21.35
22-1
6
4.15
22-2
6
3.95
22-3
6
4.45
23-1
6
4.90
23-2
6
4.75
23-3
6
3.75
24-1
6
18.60
24-2
6
3.20
24-3
6
23.75
25-1
6
15.75
25-2
6
2.50
25-3
6
2.25
3.55
3.45
2.80
3.26
I
8.25
5.60
34.25
6.90
Eained on, exclud-
5.05
ed from average
4.35
5.35
4.92
6.50
6.35
4.85
5.90
26.90
Rained on, exclud-
ed from average
4.10
Rained on, exclud-
29.15
4.10
ed from average
Rained on, exclud-
24.80
ed from average
2.85
3.05
2.95
456 University of California Publications in Agricultural Sciences [Vol. 3
Table 74 — Hanford Fine Sandy Loam, Second Crop
Oats (following milo A)
Planted, November 22, 1916. Harvested, June 18, 1917
Straw Grain Total dry matter
„ A . , A A „
t ^ r \ r "i
No. Average Average Average
weight Weight weight Weight weight Notes
2.90 6.70
1.85 5.25
3.47 2.40 2.38 5.65 5.86
Pot
plants
Weight
14-1
6
3.80
14-2
6
3.40
14-3
6
3.20
15-1
6
2.45
15-2
6
1.75
15-3
6
2.00
16-1
6
11.15
16-2
6
2.15
1.85
5.25
2.40
2.38
5.65
1.35
3.80
1.25
3.00
1.50
1.36
3.50
8.40
19.55
2.30
4.45
3.50 3.43
Eained on, exclud-
ed from average
Pot saturated with
soluble salts, ex-
cluded from av-
erage
16-3 6 1.15 2.15 0.70 2.30 1.85 4.45
19-1
6
1.75
1.25
3.00
19-2
6
4.55
2.95
7.50
19-3
6
1.35
2.55
0.95
1.72
2.30
4.27
20-1
6
10.45
6.30
16.75
Eained on, exclud-
ed from average
20-2
6
1.55
1.05
2.60
20-3
6
1.65
1.60
1.00
1.02
2.65
2.62
22-1
6
1.65
1.10
2.75
22-2
6
2.10
1.15
3.25
22-3
6
2.50
2.08
1.50
1.25
4.00
3.33
23-1
6
2.70
1.55
4.25
23-2
6
1.90
1.60
3.50
23-3
6
3.20
2.60
2.00
1.71
5.20
4.32
24-1
6
4.80
3.10
7.90
24-2
6
16.75
9.80
26.55
Rained on, exclud-
ed from average
24-3
6
3.35
4.07
2.35
2.73
5.70
6.80
25-1
6
1.95
1.30
3.25
25-3
6
2.25
2.00
1*40
1.30
3.65
3.30
25-2
6
1.80
1.20
3.00
No.
plants
Straw
Grain Total dry matter
K A
Pot
r
Weight
Average
weight
r y r y
Average Average
Weight weight Weight weight
14-1
6
4.75
4.30 9.05
14-2
6
9.22
9.00 18.22
14-3
6
11.97
8.65
10.85 8.05 22.82 16.69
1919] Pendleton: A Study of Soil Types 457
Table 75 — Hanford Fine Sandy Loam, Second Crop
Barley A (following cowpeas A)
Planted, October 30, 1916. Harvested, May 20, 1917
Notes
15-1 6 15.47 15.30 30.77 Kained on, exclud-
ed from average
3.29
4.39 4.12 3.70
6.42
2.55
4.01 1.71 3.56
1.80
1.91
2.70 2.25 1.98
2.90
2.80
3.44 7.45 2.85
2.07
3.53
4.10 2.73 2.78
3.35
4.23
6.24 4.20 3.93
2.54
9.75
3.90 3.57 3.05
1.75 4.22 Eained on, exclud-
ed from average
Pot broken, ex-
cluded from av-
erage
25-3 6 3.01 2.74 2.18 1.96 5.19 4.70
15-2
6
3.78
15-3
6
5.00
16-1
6
7.28
16-2
6
2.55
16-3
6
2.20
19-1
6
2.82
19-2
6
2.39
19-3
6
2.89
20-1
6
3.57
20-2
6
3.32
20-3
6
19.35
22-1
6
2.73
22-2
6
5.89
22-3
6
3.69
23-1
6
5.29
23-2
6
6.19
23-3
6
7.98
24-1
6
3.07
24-2
6
21.85
24-3
6
4.73
25-1
6
2.47
25-2
6
Lost
7.07
9.12
8.09
13.70
5.10
3.91
7.57
4.62
4.30
5.14
4.68
6.47
6.12
26.70
6.29
Eained on, exclud-
ed from average
4.80
9.42
6.42
6.88
8.64
10.42
12.18
10.41
5.61
31.60
8.30
6.95
458
University of California Publications in Agricultural Sciences [Vol. 3
16-3
Table 76 — Hanford Fine Sandy Loam, Second Crop
Barley B (following soy beans)
Planted, January 31, 1917. Harvested, June 21, 1917
No.
plants
Straw
Grain
Total c
r
Weight
Lry matter
Pot
r "\
Average
Weight weight
r
Weight
Average
weight
>
Average
weight
14-1
6
9.55
6.80
16.35
14-2.
6
6.05
5.40
11.45
14-3
6
3.80 6.47
2.10
4.76
5.90
11.23
15-1
6
3.50
2.80
6.30
15-2
6
3.20
1.70
4.90
15-3
6
4.05 3.58
2.60
2.36
6.65
5.95
16-1
6
3.10
1.45
4.55
16-2
6
9.20
8.20
17.40
Notes
7.35
19-1
6
3.05
19-2
6
2.65
19-3
6
2.15
20-1
6
3.35
20-2
6
4.20
20-3
6
2.55
22-1
6
2.05
22-2
6
2.90
22-3
6
3.15
23-1
6
3.10
23-2
6
3.10
23-3
6
3.40
24-1
6
3.10
24-2
6
10.10
24-3
3.05
3.10
2.62
3.36
2.70
3.20
2.65
4.50
0.80
2.20
1.85
2.60
3.20
2.15
1.75
2.35
2.25
2.05
2.95
2.75
1.45
5.80
2.35
1.45 11.85
3.85
4.85
4.00
1.61
2.65
2.12
2.58
1.90
5.95
7.40
4.70
3.80
5.25
5.40
5.15
6.05
6.15
3.70
15.90
5.40
4.55
4.23
6.02
4.82
Eained on, exclud-
ed from average
Eained on, exclud-
ed from average
Eained on, exclud-
ed from average
4.55
25-1
25-2
25-3
3.35
3.10
4.70
3.72
2.90
1.85
4.60
3.12
6.25
4.95
9.30
6.83
1919] Pendleton: A Study of Soil Types 459
Table 77 — Hanford Fine Sandy Loam, Second Crop
Melilotus indica (following cowpeas B)
Planted, November 22, 1916. Harvested, June 21, 1917
No.
plants
Straw
Unhulled seed
A
Total d
Weight
ry matter
Pot
r
Weight
Average
weight
r
Weight
Average
weight
Average
weight Notes
14-1
6
17.00
15.80
32.80
14-3
6
13.25
16.45
29.70
14-3
6
4.40
15.12
3.10
16.12
7.50
31.25 Excluded from
average
15-1
6
35.00
34.75
69.75
15-2
6
24.85
27.28
52.05
15-3
6
28.95
29.60
32.70
31.58
61.65
61.15
16-1
5
23.50
24.90
48.40
16-2
6
30.80
25.50
56.30
16-3
6
23.65
25.98
25.70
25.37
49.35
51.35
19-1
6
20.50
18.35
38.85
19-2
6
26.90
23.20
50.10
19-3
6
26.20
24.53
27.40
22.98
53.60
47.52
20-1
6
20.55
17.80
38.35
20-2
6
20.75
21.20
41.95
20-3
6
28.85
23.38
26.05
21.68
54.90
45.07
22-1
6
28.00
28.10
56.10
22-2
6
32.30
34.20
66.50
22-3
6
28.25
29.52
31.85
31.38
60.10
60.90
23-1
6
38.05
34.25
72.30
23-2
6
34.40
36.55
70.95
23-3
6
32.25
34.90
32.35
34.38
64.60
69.28
24-1
6
37.35
31.40
68.75
24-2
6
25.90
28.10
54.00
24-3
6
29.05
30.77
30.15
29.88
59.20
60.65
25-1
6
25.35
30.45
55.80
25-2
6
33.90
35.90
69.80
25-3
6
32.10
30.45
36.65
34.33
68.75
64.78
460
University of California Publications in Agricultural Sciences [Vol. 3
Table 78 — Hanford Fine Sandy Loam, Second Crop
Bur Clover (following milo B)
Planted, November 22, 1916. Harvested, June 25, 1917
No.
plants
Straw
A
Burs
A
Total dry
r
Weight
matter
Pot
Weight
Average
weight
r
Weight
Average
weight
Average
weight
14-1
7
6.70
17.55
24.25
14-2
6
7.00
16.85
23.85
14-3
6
6.10
6.60
14.50
16.30
20.60
22.90
15-1
6
13.30
29.10
42.40
15-2
6
14.45
33.10
47.55
15-3
6
17.10
14.95
26.65
29.62
43.75
44.56
16-1
6
8.85
15.40
24.25
16-2
6
12.25
29.60
41.85
16-3
6
10.05
10.38
21.90
22.30
31.95
32.68
19-1
6
9.90
19.90
29.80
19-2
6
7.70
17.80
25.50
19-3
6
8.20
8.60
22.40
20.03
30.60
28.63
20-1
6
7.90
22.50
30.40
20-2
6
9.75
23.30
33.05
20-3
6
8.70
8.78
20.50
22.10
29.20
30.88
22-1
6
15.90
38.00
53.90
22-2
6
13.20
23.40
36.60
22-3
6
14.50
14.53
31.30
30.90
45.80
45.43
23-1
6
14.45
37.40
51.85
23-2
6
13.55
27.30
40.85
23-3
6
12.05
13.35
28.00
30.90
40.05
44.25
24-1
6
10.60
24.30
34.90
24-2
6
12.10
34.10
46.20
24-3
6
10.25
10.98
24.00
27.46
34.25
38.45
25-1
6
17.90
40.00
57.90
25-2
6
14.60
30.80
45.40
25-3
6
13.35
15.28
26.40
32.40
39.75
47.68
Notes
San Joaquin sandy loam. — The samples of this type were the last
to be weighed into pots and planted, because of the lack of available
greenhouse space ; therefore the time allowed for the growing of but
one crop, instead of two, on each pot of soil. The crops used were
wheat, barley, rye, oats, bur clover (Medioago sp.), and Melilotns
indioa. As was done for the other types, an excess of seed was
planted. When the plants were well established, thinning reduced
the number to six plants per pot.
Since the specific gravity of this soil was high, because of the large
amount of quartz and the small amount of organic matter in its com-
position, six kilos of soil, instead of five, were weighed out into each
pot. The samples of this type have the very annoying peculiarities
of becoming very mushy if an excess of water be added, and of setting
1919] Pendleton: A Study of Soil Types 461
with a very hard surface on drjdng. This makes the soils hard to
handle in greenhouse pot culture work.
The variation in crop growth from soil to soil, as shown by the
total dry matter produced (tables 79-84 and fig. 32), is rather
marked. That the several samples do not show equal crop producing
powers is very evident, though with regard to the several indicator
crops the soils would frequently not maintain the same order. Soil
no. 26 gave the poorest yields with all six crops. Except for wheat,
the soils nos. 10, 11, and 12 gave low yields with both the grains and
the legumes. It is interesting to note that wheat gave relatively high
yields with a number of the soils, and wheat has probably been raised
on these soils more than any other one crop. This series shows that,
as far as the samples represent the type and the crops used represent
crops as a whole, the soils mapped under a given type name are not
closely similar in crop producing power under greenhouse conditions.
Table 79 — San Joaquin Sandy Loam
Rye
Planted, November 22, 1916. Harvested, June 21, 1917
No.
plants
Sti
raw
Grain
Total dry
r
Weight
matter
Pot
Weight
Average
weight
r
Weight
Average
weight
Average
weight Not
10-1
6
1.70
0.30
2.00
10-2
6
2.30
0.35
2.65
10-3
6
2.05
2.02
0.65
0.43
2.70
2.45
11-1
6
3.15
0.70
3.85
11-2
6
2.25
0.70
2.95
11-3
4
3.20
2.87
0.70
0.70
3.90
3.57
12-1
6
1.65
0.45
2.10
12-2
6
2.45
0.85
3.30
12-3
6
2.40
2.17
0.65
0.65
3.05
2.82
13-1
6
4.20
1.25
5.45
13-2
6
4.30
0.80
5.10
13-3
6
3.75
4.08
1.60
1.22
5.35
5.30
17-1
6
7.55
1.60
9.15
Rained on
17-2
6
1.95
0.55
2.50
17-3
6
1.80
1.87
0.45
0.50
2.25
2.37
18-1
6
2.35
0.85
3.20
18-2
6
0.90
0.30
1.20
18-3
6
3.70
2.32
1.20
0.78
4.90
3.10
21-1
6
2.20
0.80
3.00
21-2
6
2.70
0.95
3.65
21-3
6
6.55
2.45
2.35
0.87
8.90
3.33 Rained on
26-1
6
1.50
0.60
2.10 .
26-2
6
2.55
0.75
3.30
26-3
6
2.50
2.18
0.70
0.68
3.20
2.87
462
University of California Publications in Agricultural Sciences [Vol. 3
65
60
.35
50
45
40
85
30
25
20
15
10
/
/
\
1
V
__L
/
/
\
\
/
\
\
\
T
1
1
/
/
/
\
\
\
1
1
/
/
/
N
^\
1
1
/ /
/ /
/ /
/ /
1 /
\
w
\
~~~~~^-' :s *-,
t
**X'
"■•"^r.""^
marAMk -
?C
^"* '"•. *S
Melilotus
Bur
Clover
Barley B
Barley A
Oats
Wheat
14 15 16 19 20 22 23 24 25 Soils
Fig. 33. Graph showing the total dry matter produced by wheat, oats,
barley (two series), bur clover, and Melilotus indica on the nine samples of
Ilanford fine sandy loam. Second crop.
1919] Pendleton: A Study of Soil Types 463
Table 80 — San Joaquin Sandy Loam
Barley
Planted, October 30, 1916. Harvested, June 17, 1917
Straw Grain Total dry matter
Pot
No.
plants
r
Weight
Average
weight
r
Weight
Average
weight
r
Weight
Average
weight Notes
10-1
6
2.93
0.92
3.85
10-2
6
1.87
0.81
2.68
10-3
6
1.47
2.09
0.85
0.86
2.32
2.95
11-1
6
1.91
0.66
2.57
11-2
6
2.02
1.28
3.30
11-3
6
2.97
2.30
0.90
0.95
3.87
3.25
12-1
6
10.27
4.95
15.22
Eained on; exclud-
12-2
6
3.60
1.32
4.92
ed from average
12-3
6
3.49
3.54
0.43
0.87
3.92
4.42
13-1
6
2.14
1.46
3.60
13-2
6
3.19
1.78
4.97
13-3
6
3.28
2.87
1.77
1.67
5.05
4.53
17-1
6
3.89
2.17
6.06
17-2
6
3.74
1.80
5.54
17-3
6
2.44
3.35
0.80
1.59
3.24
4.95
18-1
6
4.65
1.93
6.58
18-2
6
3.74
1.94
5.68
18-3
6
5.61
4.66
2.34
2.07
7.95
6.74
21-1
6
2.05
1.53
3.58
21-2
6
2.10
1.80
3.90
21-3
6
3.81
2.65
2.33
1.88
6.14
4.54
26-1
6
1.12
0.63
1.75
26-2
6
1.08
0.41
1.49
26-3
6
1.20
1.13
0.70
0.58
1.90
1.71
464 University of California Publications in Agricultural Sciences [Vol. 3
Table 81 — San Joaquin Sandy Loam
Wheat
Planted, October 30, 1916. Harvested, June 21, 1917
Straw Grain Total dry matter
Pot
No.
plants
Weight
Average
weight
f
Weight
*>
Average
weight
r
Weight
Average
weight Not
10-1
6
3.59
0.85
4.80
10-2
6
3.45
0.45
3.90
10-3
6
6.35
4.58
0.75
0.68
7.10
5.26
11-1
6
5.60
1.15
6.75
11-2
6
2.75
0.60
3.35
11-3
6
3.45
3.93
0.70
0.81
4.15
4.75
12-1
6
6.85
2.00
8.85
12-2
6
7.50
1.35
8.85
12-3
6
4.45
6.27
1.35
1.56
5.80
7.83
13-1
6
3.90
0.85
4.75
13-2
6
3.25
0.45
3.70
13-2
6
3.95
3.70
0.75
0.68
4.70
4.38
17-1
6
2.70
0.25
2.95
17-2
6
1.20
0.45
1.65
17-3
6
2.75
2.21
none
0.23
2.75
2.45
18-1
6
5.90
1.50
7.40
18-2
6
7.90
2.40
10.30
Rained on
18-3
6
5.00
5.45
1.00
1.25
6.00
6.70
21-1
6
3.10
1.05
4.15
21-2
5
4.30
0.75
5.05
21-3
6
8.40
3.70
2.45
0.90
10.85
4.60 Rained on
26-1
6
2.35
0.55
2.90
26-2
6
0.40
none
0.40
Rained on
26-3
6
2.60
2.47
0.35
0.45
2.95
2.92
1919] Pendleton: A Study of Soil Types 465
Table 82 — San Joaquin Sandy Loam
Oats
Planted, November 22, 1916. Harvested, June 17, 1917
Straw Grain Total dry matter
Pot
No.
plants
r
Weight
Average
weight
r
Weight
Average
weight
Weight
Average
weight
10-1
6
2.25
0.90
3.15
10-2
6
3.65
1.90
5.55
10-3
6
1.70
2.53
0.50
1.10
2.20
3.63
11-1
6
2.25
1.25
3.50
11-2
6
1.75
0.95
2.70
11-3
6
2.10
2.03
1.00
1.07
3.10
3.10
12-1
6
1.70
0.90
2.60
12-2
6
2.40
1.00
3.40
12-3
6
2.35
2.15
1.05
0.98
3.40
3.13
13-1
6
2.25
1.20
3.45
13-2
6
2.40
1.10
3.50
13-3
6
2.70
2.45
1.70
1.33
4.40
3.78
17-1
6
0.80
0.55
1.35
17-2
6
1.50
0.90
2.40
17-3
6
1.25
1.90
0.70
0.72
1.95
1.90
18-1
6
1.70
1.00
2.70
18-2
6
1.15
0.60
1.75
18-3
6
1.10
1.32
0.50
0.70
1.60
2.02
21-1
6
1.85
0.95
2.80
21-2
6
2.35
1.05
3.40
21-3
6
1.00
1.73
0.55
0.85
1.55
2.58
26-1
6
1.55
0.60
2.15
26-2
6
1.35
0.80
2.15
26-3
6
1.65
1.52
0.70
0.70
2.35
2.22
Notes
466 University of California Publications in Agricultural Sciences [Vol. 3
Table 83 — San Joaquin Sandy Loam
Bur Clover
Planted, November 22, 1916. Harvested, June 17, 1917
Straw Seed in burs Total dry matter
Pot
No.
plants
Weight
Average
weight
r
Weight
Average
weight
r
Weight
Average
weight Notes
10-1
6
0.50
0.95
1.45
10-2
6
1.50
1.65
3.15
10-3
6
0.50
0.83
1.75
1.45
2.25
2.28
11-1
6
0.90
2.00
2.90
11-2
6
0.25
1.00
1.25
11-3
6
0.30
0.48
1.10
1.37
1.40
1.85
12-1
6
0.90
3.00
3.90 .
12-2
6
2.15
5.30
7.45
12-3
6
1.50
1.52
1.90
3.40
3.40
4.92
13-1
6
1.55
3.45
5.00
13-2
6
0.75
2.80
3.55
13-3
6
4.35
1.15
5.70
3.12
9.05
4.27 Excluded from av-
erage
17-1
6
0.70
2.05
2.75
17-2
6
2.35
3.85
•
6.20
Excluded from av-
erage
17-3
6
0.90
0.80
1.70
1.87
2.60
2.67
18-1
6
1.20
3.40
4.60
18-2
6
3.25
6.65
9.90
Excluded from av-
erage
18-3
6
1.80
1.50
4.85
4.12
6.65
5.62
21-1
6
3.35
3.70
7.05
21-2
6
2.00
3.90
5.90
21-3
6
1.75
2.37
5.15
4.25
6.90
6.62
26-1
6
0.60
1.45
2.05
26-2
6
1.20
2.75
3.95
26-3
6
0.40
0.73
1.30
1.83
1.70
2.56
1919] Pendleton: A Study of Soil Types 467
Table 84 — San Joaquin Sandy Loam
Melilotus indica
Planted, November 22, 1916. Harvested, June 21, 1917.
Notes
No.
plants
Sti
A
•aw
Unhull
ed seed
A
Total dry
Weight
matter
Pot
r
Weight
Average
weight
r
Weight
Average
weight
Average
weight
10-1
6
1.20
1.20
2.40
10-2
6
1.03
0.92
1.95
10-3
6
1.30
1.18
1.65
1.26
2.95
2.44
11-1
6
1.05
0.85
1.90
11-2
6
0.50
0.35
0.85
11-3
6
1.00
0.85
0.80
0.67
1.80
1.52
12-1
6
1.07
2.05
3.12
12-2
6
1.70
2.45
4.15
12-3
6
1.20
1.33
1.40
1.96
2.60
3.29
13-1
6
3.05
3.70
6.75
13-2
6
3.10
3.95
7.05
13-3
6
3.50
3.22
4.45
4.03
7.95
7.25
17-1
6
3.05
4.05
7.10
17-2
6
2.25
3.55
5.80
17-3
6
2.85
2.72
3.20
3.60
6.05
6.32
18-1
6
3.25
3.90
7.15
18-2
6
2.05
2.65
4.70
18-3
6
2.85
2.42
3.95
3.50
6.80
6.22
21-1
6
2.50
3.40
5.90
21-2
6
2.65
3.95
6.60
21-3
6
3.45
2.87
3.30
3.55
6.75
6.42
26-1
6
1.10
0.85
1.95
26-2
6
0.95
0.85
1.80
26-3
6
1.30
1.12
1.05
0.92
2.35
2.04
GENERAL DISCUSSION
The limited time available for this study made it impossible to
make all the determinations upon each of the several horizons of all
the soils collected for this study.
It was believed, however, that the additional data were not re-
quired, since that already at hand seemed to give ample evidence upon
which to base conclusions. Therefore, in many cases determinations
were run on the surface horizon only. This makes some of the tables
appear incomplete.
468 University of California Publications in Agricultural Sciences [Vol. 3
On the basis of the preceding results and discussions some general
treatment is possible, as well as a more or less critical discussion of the
methods of soil surveying pursued by the Bureau of Soils.
The types and the localities of collection of the soils studied were
as follows :
Diablo clay adobe: Thalheim (17)
San Juan Capistrano (1) Madera (18)
Los Angeles (2) Merced (21)
Calabasas (5) Del Mar (26)
Danville (6) Kan ford fine sandy loam:
Altamont clay loam Elk Grove (14)
Walnut (3) Acampo (15)
San Fernando Valley (4) Woodbridge (16)
Mission San Jose (7) Waterford (19)
Sa?i Joaquin sandy loam: Snelling (20)
North Sacramento (10) Basset (22)
Lincoln (11) Anaheim (23)
Wheatland (12) Los Angeles (24)
Elk Grove (13) Van Nuys (25)
Note. — Figures following localities designate sample numbers.
Comparisons of Physical Data
The mechanical analyses of the soils were carried out with both
the Hilgard elutriator and the Bnrean of Soils centrifuge methods.
The tedious nature of the elutriator method has been emphasized else-
where. The results by this method show that the soils of each type
as a whole are somewhat similar, though no two are identical and
some samples of a type are widely divergent from the rest. The
Bureau of Soils method appears to give a sharper and more satisfac-
tory separation into classes than does the elutriator method. This is
to be expected since the separates represent greater ranges of particle
sizes. As a check on the texture of the samples collected, it shows that
some of the soils are not true to name, therefore that all soils mapped
under a given type name are not closely similar to one another. Of
course, this is the belief of many soil surveyors, but it seems strange
that in the present work, where there was the attempt to select soils
representative of the class and type chosen for study, that such diver-
gences developed. It is an interesting commentary on the personal
equation of the field worker, in this case of the writer, who collected
the samples.
1919 j Pendleton: A Study of Soil Types 469
With regard to the methods of mechanical analysis, one should not
overlook Mohr's work on The Mechanical Analysis of Soils of Java, 30
which gives an excellent discussion of the relative merits of the better
known systems of mechanical analysis. He describes a modified cen-
trifuge method preferred by him.
Under a discussion of the physical constants of soils, Free 31 dis-
cusses the value of mechanical analysis as a soil constant, and shows
that there are three serious errors in the determination, all of which
impress themselves upon one making and using such analyses. They
are: "(1) disunity of expression; (2) failure to express conditions
within the limits of individual groups; and (3) failure to take
account of variations in the shapes of the particles." Yet he empha-
sizes, and rightly so, i l that mechanical analysis is by no means useless
nor to be belittled as a means of soil investigation." 32
Moisture equivalents. — This determination showed quite distinct
averages for the types, though there was considerable variation within
each of the types. Eliminating those samples shown to be non-typical
according to the mechanical analysis, the variation within the type is
reduced considerably. Yet it cannot be said that as regards this con-
stant that all soils mapped under a given type name, or even those
soils under a given type name which the mechanical analysis has
shown to be true to name, have closely similar moisture equivalents.
Briggs and McLane 33 express the belief that ultimately moisture
equivalent determinations will replace mechanical analysis in the
classification of soils, because the determination is simple and the
result can be expressed as a single constant.
Hygroscopic coefficient. — The two heavy types show averages dis-
tinct from those of the two light types, but the wide and erratic varia-
tion within the type, together with the nearly universal failure of
Briggs and Shantz's formula 34 to convert these values into values
even approximating those of the moisture equivalent, leads one to
doubt the accuracy of these figures of the hygroscopic coefficient. It
is because of the ease of determining the moisture equivalent, and
because of the difficulties involved in correctly carrying out the hygro-
scopic coefficient, that the doubt is cast upon the latter determination.
so Bull. Dept. of Agr., Indes Neerland, 1910, no. 41, pp. 33.
3i Free, E. E., Studies in Soil Physics, Plant World, vol. 14 (1912), nos. 2,
5, 7, 8.
32 ibid., p. 29.
33 Proc. Amer. Soc. Agron., vol. 2 (1910), pp. 138-47.
34 U. S. Bur. PI. Ind., Bull. 230 (1912), p. 72.
470 University of California Publications in Agricultural Sciences [Vol. 3
Comparison of Chemical Data
The total nitrogen content of the samples of each type varies
within somewhat wide limits. The average amounts for the several
types are distinct, though the variations are such that some of the
quantities of one type overlap those of another type. It is believed
that for the types selected the field differentiations do indicate dif-
ferences.
Eegarding the humus content of the four types under considera-
tion, the results are somewhat different. The average amounts of
humus are almost alike in three of the four types, while the nitrogen-
poor San Joaquin soil has an average of about half that of the others.
Within the type the soils may be very nearly alike in the humus con-
tent, as is the case in two of the types, or may be widely variable, as
in the Hanford fine sandy loam. It should be noted that the amount
of humus as shown by the method used, is not indicated by the inten-
sity of the color either of the soil or of the resulting extract. This
confirms the findings of Gortner, which are cited elsewhere.
There was quite a wide range shown in the results of the deter-
mination of the loss on ignition. The Diablo and Altamont soils, be-
cause of the heavier textures and the relatively large amounts of com-
bined water, and of considerable amounts of CaC0 3 in at least one
case, gave high losses on ignition. The averages were close, 6.8% for
the Diablo, and 6.7% for the Altamont. The Hanford soils were
lower, though with a wider range. Soil no. 14, with 6.9% loss on igni-
tion, shows almost double that of any other soil in the type. The San
Joaquin soils, with an average of 2.6%, show the lowest average loss
on ignition. The smaller amounts of organic matter in these soils is
one reason for the smaller loss. The two heavier types have averages
close together, and the lighter types have averages not far apart, but
because of the wide variations within each type, the results of the
determination of the loss on ignition certainly do not show that all
soils classified in one type are closely similar.
Hall and Russell, in their discussion of the soils of southeastern
England, 35 consider of value the ratio of Q-. — — : A — but apply-
% loss on ignition,
ing this ratio to the California soils under consideration does not seem
to give any relations of value. The Diablo ratio varies from 0.0136 to
0.0158, the Altamont from 0.0141 to 0.0204, the San Joaquin from
0.0144 to 0.0232, and the Hanford from 0.011 to 0.0172.
85 Jour. Agr. Sci., vol. 4 (11)11), pp. 182-223.
1919] Pendleton: A Study of Soil Types 471
The calcium (as CaO) content of the soils is interesting especially
because of the variability. The Altamont samples show the greatest
variation, for the largest quantity of CaO is about seven times the
smallest. The San Joaquin samples are second, with the largest over
six times the smallest. The Diablo samples are third, with the largest
over five times the smallest, while the Hanford soils show the least
variation, the largest being less than twice the smallest. There are
quite marked differences between the averages of the Diablo, Alta-
mont, and Hanford soils (the San Joaquin samples are intermediate),
but the wide variations within the types greatly minimize any sig-
nificance the averages might have. Hence it is not possible to state
that one or another type, as represented by these samples, is charac-
terized by high, low, or moderate amounts of calcium.
As the analyses of the samples for calcium failed to point out any
striking characteristics, unless it be that of variability, so it is with
magnesium. Magnesium (as MgO) is variable within each of the four
types. The largest quantity is about three times the smallest in the
Diablo, San Joaquin, and Hanford types, while in the Altamont the
largest is twenty-seven times the smallest. Considering the Hanford
and San Joaquin, or the Diablo and San Joaquin, it is seen that the
curves do not overlap, while the Diablo and Altamont, or the Diablo
and Hanford curves do. The averages of the four types are distinct,
except between the Hanford and Diablo, which are quite close. But,
here again, because of the more or less wide range of values within
each of the types, the averages are of little significance. The lime-
magnesia ratio is very variable in these soils. Comparing the calcium
and magnesium curves for the several soils gives a good idea of the
relations. The Diablo curves are quite similar except for soil no. 6,
which shows 3% MgO and 0.5% CaO. In the Altamont soils the
curves are somewhat similar in direction, though the ratios differ
widely. In the Hanford and San Joaquin types the ratios of CaO and
MgO are also far from constant, yet it is readily seen from the graphs
that the amount of magnesium varies more or less directly with the
amount of calcium.
Respecting the total phosphorus (as P 2 5 ), if the San Joaquin and
Hanford samples alone be considered, there would be no doubt as to
the significance of the field separation, the variations within the type
notwithstanding. But when the other two types are considered, the
case is not so good in favor of the field classification. The Diablo soils
show considerable variation in the amount of P r ,0 2 , while the three
472 University of California Publications in Agricultural Sciences [Vol. 3
Altamont samples show much variation. Therefore with reference to
the amount of phosphorus, and the types studied, the separation into
types may or may not be of significance.
If the results of the potassium (K 2 0) determinations are com-
pared, it is very evident that but one conclusion can be drawn, and
that is that the variations in the amount of potassium within each
type are great enough so that any differences between the averages
of the several types have no significance whatsoever. Therefore, with
regard to total potassium the field separation of soils as represented
by these twenty-four samples of four types means nothing.
Comparison of Bacteriological Data
The wealth of the data obtained from over nine hundred bacteri-
ological tumbler cultures is hardly of sufficient significance to com-
pensate for the effort involved. There is one outstanding conclusion
from all this work, namely, the lack of any very definite, distinct, and
constant bacteriological activity of the samples of one type that is not
to a considerable extent shared by the samples of the other types.
There are tendencies in certain types with regard to bacteriological
activity which show that some of the types as a whole are more or less
distinct from one or more of the others.
Ammonification. — The amount of ammonia produced from dried
blood varies to a great extent. The Altamont samples gave between
10 and 33 mg. nitrogen as ammonia; the Diablo samples gave between
7 and 26 mg., and the Hanford samples gave between 35 and 72 mg.
The Altamont and Diablo types are thus seen to be about alike in their
low ammonifying power, as compared with the higher ability of the
San Joaquin types and still greater ability of the Hanford types.
And since there are somewhat greater variations between the types
than between the samples of a given type, the ammonifying power
may be significant.
Nitrogen fixation. — The two heavy types, Diablo clay adobe and
Altamont clay loam, show no characteristic differences, while the two
lighter types show considerable differences. As a whole the types are
different one from another, yet the variations within the type are
sufficient to prevent any statement that the rate of nitrogen fixation
is a function of the type as determined in the field, or vice versa.
Nitrification. — The nitrification data are the most puzzling. The
figures are extremely variable within a given type ; the erratic way
1919] Pendleton: A Study of Soil Types 473
in which the Hanford samples behave is not paralleled by any other
type. There are certain ways in which the types are distinct :
The nitrification of the soil's own nitrogen as compared with the
soil's action upon added nitrogen is in some degree separate for each
type. The San Joaquin samples nitrified their own nitrogen to a
greater degree than they did the nitrogen added to the soil.
The relative nitrification of the several nitrogenous materials
(dried blood, cottonseed meal, ammonium sulfate) is in some measure
distinct for the several types. The Diablo, Altamont, and San Joaquin
types show ammonium sulphate to be nitrified the best, cottonseed meal
less, and dried blood still less. The Hanford samples show cottonseed
meal to give the highest percentage of nitrates, with dried blood less,
and ammonium sulfate still less.
When any one soil is compared through the three sets of deter-
minations there are no apparent similarities. The Hanford type
shows the greatest bacterial activity, while the San Joaquin shows
less, with the heavier types showing sometimes greater activity and
sometimes less than that of the San Joaquin.
Work in Other States
In connection with the original chemical work reported in this
paper, there should be mentioned the large amount of work done in a
number of states on the analysis of the types of soils as mapped by
the Bureau of Soils. Apparently, these analyses have been made
without any question as to the validity of the. existing subdivisions
into types. The various analyses have been reported with some com-
ment, but that which does appear usually deals with the "adequacy"
or " inadequac3 T " of the plant food present. Blair and Jennings 36
present a large amount of data on chemical composition, some of
which on rearrangement show interesting relationships (table 85).
From the data the four series of soils with the largest number of
analyses were selected (see following table). Under each series there
are from 2 to 4 soil tj^pes, and from 2 to 6 analyses under each type.
The averages from each type are tabulated, also the averages of all
the types within the series. This is both for the strong acid extraction
and the fusion methods of analysis for significant plant food elements.
There are no doubts but that each series of soils shows characteristic
chemical peculiarities, peculiarities which are to a great extent con-
36 The Mechanical and Chemical Composition of the Soils of the Sussex Area,
New Jersey, Geol. Surv. N. J., Bull. 10, 1910.
474
University of California Publications in Agricultural Sciences [Vol.3
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1919] Pendleton: A Study of Soil Types 475
stant throughout the several representatives of the type. In some
cases, the differences or similarities are more clearly seen in the total
analyses, and in other cases, they appear in the acid analyses and not
in the fusion analyses. Within any series the variations between
analyses of any one type are about the same as the variations from
type to type. There are many other papers 37 which provide material
for similar comparisons.
A paper by Van Dyne and Ashton 38 reports chemical analyses for
lime, phosphoric acid, potash, and nitrogen on the samples collected
in the course of the survey of Stevens County, Washington. Though
sometimes there is a much greater range within a type than between
types, in a general way the analyses for any one type agree quite
well. As a whole the chemical analyses seem to show that the field
criteria are also a basis for grouping soils into certain chemical
groups. It should be mentioned that the work of Blair and Jennings,
also that of Van Dyne and Ashton, deals with individual areas, and
not with samples from several scattered areas. The work of Fraps and
Williams, and the original work here reported represent scattered
areas.
The Greenhouse Cultures
By far the most interesting results were obtained in the pot culture
work. It is realized that there are variations in the physical nature
of the samples of a given type, yet since these samples were collected
with considerable care by one familiar with field classifications, the
samples so selected should be fairly representative of the type. It is
probable that if all the soils in each of the types used were exactly the
same in texture, i.e., if the mechanical analysis showed the same
results for the several soils, the crops produced on the several soils of
a type would be less divergent in appearance or weight. Yet it is
not at all likely that the crops would be the same. Pot cultures pre-
sume that the conditions in all the pots can be kept uniform, but this
is obviously impossible. Greenhouse work is subject to many interfer-
ing factors. Nevertheless, the results are believed to be significant,
37 Williams, and others, Eeport on the Piedmont Soils, North Carolina Dept.
Agr., Bull. 206, 1915.
Fraps, G. S., Composition of the Soils of South Texas, Texas Agr. Exp. Sta.,
Bull. 161, 1913; Composition of the Soils of the Texas Panhandle, ibid., Bull.
173, 1915.
38 Van Dyne and Ashton, Soil Survey of Stevens County, Washington, Field
Operations, U. S. Bur. Soils, 1913, pp. 2165-2295.
476 University of California Publications in Agricultural Sciences [Vol.3
despite the large correction that the consideration of the probable
error might introduce.
The differences in the crop producing power of the soils are very
marked in the Diablo clay adobe, where the second crop, as well as
the first, shows evident variations in the ability to support a crop.
In the Altamont clay loam the second crop almost loses the variations
seen in the first crop from pot to pot. The samples of both types
seem to show one thing in common — the approach of the several sam-
ples toward a uniform ability to produce crops, as the soils are kept
for longer periods under the same conditions. The Hanford soils did
not show, with the several crops, the parallelism in the fertility from
crop to crop as did the Diablo and Altamont soils. Some soils pro-
duced good crops of grain and poorer crops of legumes, others did the
opposite. The low nitrogen content in this type seemed to be a limit-
ing factor. This would account for the variation between the grain
and the leguminous crops. Also, the presence, or absence of Bacillus
radicuola inoculation in this connection might greatly affect the total
crop produced.
There does not seem to be much doubt but that the soils of the
several types compared in this way are not the same, though they are
in certain respects similar.
The Place of Soil Classification. — With all these evidences that the
soils within the several types are not closely similar, though they are
classified the same by the Bureau of Soils, what conclusion is one to
reach as to the value of such a classification ? If it were true that there
were no appeal from the findings of such laboratory and greenhouse
<l<-1<'rminations as these, and that these determinations were a final
proof of the fertility or infertility of a soil, obviously there would be
but one thing to do — discard all such field classifications as useless.
But the writer is one of a great many soilists who are not willing to
rely on laboratory or even greenhouse results for an absolute deter-
mination of fertility, and for the grouping together of soils into a
workable classification. Not enough is definitely known as to the mean-
ing of such findings, though there are certainly many valuable points
shown by laboratory analyses. 89
As examples of the value of natural classifications we may con-
sider those of botany, /oology, or mineralogy. If available, a wholly
satisfactory classification of soils would be equally useful. The appre-
89 Jordan, W. H., Measurements of Soil Fertility, New York Agr. Exp. Sta.
Geneva', Bull. 424, L916.
1919] Pendleton: A Study of Soil Types 477
ciation of this is shown in the many systems of soil classification that
have been proposed.
Despite the foregoing facts that have been obtained showing the
divergent properties of different samples of one type presumabi}'
alike, yet it must be admitted that soil surveys, even such as are no
more refined than those of the Bureau of Soils, have considerable
value for field use.
It is felt that the additional effort required to modify the practices
of the Bureau of Soils in the mapping and classifying of soils would
be more than justified by the increased accuracy and usefulness of
the maps. To point out some of the causes of the present practices
and to give suggestions for possible methods of improvement, the
following discussion of the Bureau of Soils methods has been
prepared.
Discussion of the Bureau of Soils' methods. — The methods of map-
ping and classifying soils, as devised and used by the Bureau, have
resulted from some definite and important considerations.
1. The necessity for keeping down the cost of surveying and map-
ping prevents the use of laboratory and culture methods in the study
of the soils classified, even if it were not for the fact that one of the
outstanding policies of the Bureau apparently denies the validity of
such studies in the classification of soils. This does not include the
mechanical analysis of soils, which is not a separate laboratory deter-
mination, but a method of checking the field man's decision as to the
texture. It should also be added that some of the reports as published
in the Field Operations of the Bureau of Soils, for 1913, show the
subdivision of the soils into two groups based upon the CaC0 8 content.
Keeping down the cost has also prevented the use of sufficient time to
map the soils correctly, even according to the criteria admittedly of
value in the system adopted. Many of the other methods of classify-
ing and mapping soils, even if applicable to most of the agricultural
regions of the United States, would be absolutely out of the question
on account of cost.
2. The large and widely diversified area of the United States, and
the attempt to map representative areas in various parts of the coun-
try, early led to difficulties. There seemed to be a lack of understand-
ing as to what criteria to use in the classification of the soils. Re-
cently, some of the areas first mapped in the state of California have
been resurveyed. The texture, series, and province differences of the
early mapping seem not to have been clear. For example, we may con-
478 University of California Publications in Agricultural Sciences [Vol.3
sider the differences between the older and the recent survey of two
localities east of Los Angeles. The notes were made by C. J. Zinn,
a member of the party which made the recent survey :
Locality A — About 15 square miles with Eaton Wash on the west, center of
Monrovia on the east, mountains on the north, and a line about 3 miles south of
mountains as the south boundary. The old survey^ has four types of three series
and two miscellaneous types: San Gabriel gravelly loam, San Gabriel gravelly
sand, Placentia sandy loam, San Joaquin black adobe, and Eiverwash and Moun-
tains. The new survey (1915, unpublished) has 13 types of 6 series and 3 mis-
cellaneous types: Hanford stony sand, gravelly sand, loam, sandy loam, fine
sandy loam, and sand; Tejunga stony sand; Zelzah loam and stony loam; Pla-
centia loam, Holland loam, Chino loam and silt loam. The miscellaneous types
are Eough Mountain land, Eough Broken land, and Eiverwash.
Locality B — In the city of Pasadena, comprising about 3.5 square miles, with
the southwest corner at the center of the city. The old survey 41 shows San
Gabriel loam occuping about 0.6 of the area, San Gabriel gravelly sand about 0.3,
and Placentia sandy loam about 0.1. The new survey (1915, unpublished) shows
Zelzah gravelly loam occupying about 0.9 of the area, Zelzah loam about 0.1, with
a very small body of Holland loam. The older survey showed a recent alluvial
soil where the recent one shows an old valley filling soil.
Besides these errors (detected as such by the practical man, who
might attempt to use the soil maps in the field) there are in addition
those of another nature which were the source of much criticism in the
earlier history of the survey — the so-called "procrustean classification"
criticism of Hilgard. 42 Due apparently to an insufficient study of the
soils of the United States, there was the attempt to classify in the same
series soils of widely differing properties — differences of an important
nature being ignored.
At the present time there is an increasing tendency toward limit-
ing series groups of soils to a more or less definite climatological
region. In this connection see the later changes in the correlation of
many soils. 43 These changes tend to limit the geographic range of the
series, and make these series narrower and more exact. Moreover, it
is understood that as the knowledge of the soils has increased, the
changes in correlation have been proceeding rapidly since the above
list was issued. This indicates that as the facts accumulate the "pro-
erustean classification" criticism is losing its force.
40 Field Operations of the U. S. Bur. of Soils, 1901, San Gabriel sheet.
4i Ibid.
« Hilgard, E. W., arid Loughridge, R. H., Proc. Second Intern. Agrogeol.
Conf., Stockholm, 1910, pp. 228-29; Hilgard, E. W., U. S. Office Exp. Sta., Bull.
142 (1904), p. 119; Hilgard, E. W., Proc. First Intern. Agrogeol. Conf., Budapest,
1909, y.p. 52-54.
M II. S. Bur. Soils, Bull. 90, 1913.
1919] Pendleton: A Study of Soil Types 479
3. There was a lack of trained men early in the work. This was
to be expected. As has been shown, the early surveys were very crude
in certain places. It must be added that some of the errors and omis-
sions made in the more recent maps are not due to a lack of training,
but to the carelessness of the field men with respect to details.
4. The policy of the Bureau has been to recognize the physical
characteristics of the soil as factors in fertility to the virtual exclusion
of the chemical or biological factors. Therefore the use of physical
criteria is necessary. Besides, the criteria must be such as can be
applied in the field, and are: "(1) color, (2) texture, determined by
rubbing between the thumb and finger, (3) structure, (4) nature of
subsoil, (5) presence of hardpan, (6) height of water table, (7) pres-
ence of alkali, (8) topography, (9) physiographic form and hence
mode of formation, and (10) source of material (sedimentary, igne-
ous, or metamorphic rocks). Humus, and the presence or absence of
appreciable quantities of lime, also the reaction of the soil (acid or
alkaline) are frequently guessed at. These criteria are practically
the only ones that can be applied in field work. It is believed that
these same criteria indicate the chemical nature of the soil, though
there has been no attempt to correlate some of the factors. However,
the original work reported in this paper would indicate that the chem-
ical nature is not the same, of soils classified the same by the Bureau
of Soils criteria.
5. The desire to limit the number of groups of soils is a wholly
sound one. In discussing the problems of classifying soils there
should always be kept in mind the fact that some of the problems are
not very different, fundamentally, from some of the problems that
have been causing perplexity among biologists for a long while.
The tendency, as seen in some of the recent surveys, to make the
series more inclusive and to introduce the term, phase, is heartily
commended. By making the series broader there will be less difficulty
in placing a soil in its proper group. The phase will take care of many
of the series differences between area and area.
6. It seems certain that if there were more emphasis placed upon
the inspection of the area, during the progress of the field work and
after its completion, there would be a much closer approach to
accuracy throughout the map and report. At the present time the
field man is not closely checked up. The careless or indifferent worker
can map more or less as he pleases, especially in the out-of-the-way
places.
480 University of California Publications in Agricultural Sciences [Vol. 3
7. Whether the soil survey should include more than a simple
classification of the soils or not, is an unsettled question. It is thought
hardly possible that in a soil survey the field man could handle all the
phases of an agricultural survey of an area, when his energies should
be fully employed in the classification of the soils. It is believed that
the place of the survey, in this country at least, is to handle the
classification of the soils, leaving the study of the remaining factors
largely to other specialists, who would use the soil survey as a basis. 44
But to make the soil maps of more general use for such work, they
must be more accurate. These maps never can become the basis of
other agricultural studies as long as many experiment station workers
ridicule them. Hence, the ultimate effort of the survey should be
toward better work, rather than covering a wide range of agricultural
studies.
8. There is not the incentive to make as many separations of the
soils in the field, as the field man might think best, because frequently
the feeling of the editors is that there would be too many small bodies
of soil shown on the manuscript maps which would not warrant the
additional cost of publication.
In conclusion, the Bureau of Soils' system has much to commend
it as a field method, and the resulting maps and classification are be-
lieved to be of distinct value. It is felt that a more general under-
standing of: (1) the limitations under which the maps, the earlier
ones especially, have been made; (2) the difficulties under which the
field work is at present carried on; (3) the meaning of the correlation
of soils; and (4) the general policy of the Bureau of Soils would give
people more sympathy with their work.
44Fippin, E. O., Proc. Amer. Soc. Agron., vol. 1 (1908), pp. 191-97.
1919] Pendleton: A Study of Soil Types 481
SUMMARY
Presumably typical samples of four soil types were collected for
laboratory and greenhouse study from widely distributed localities in
the state of California. The field appearance of each sample was
usually sufficient to warrant the classification as it exists.
Physical Relations
1. The mechanical analysis by the Hilgard elutriator shows that
the soils of a given type are in some cases quite divergent from each
other in their content of certain of the sizes of particles. The mechan-
ical analysis by the Bureau of Soils method shows that 6 of the 24
soils were not true to their type names, and that of those soils within
the type there is considerable variation.
2. The moisture equivalents for the several types show distinct
enough values to substantiate the field separation.
3. The hygroscopic coefficients vary widely within each type and
the types are not shown to be distinctly different by this criterion.
Chemical Relations
1. The total nitrogen averages vary markedly from type to type,
with the Altamont clay loam containing three times that in the San
Joaquin sandy loam.
2. The average humus content of the San Joaquin samples is
about half that of the other types. The variations in the humus con-
tent between the types are small, considering the diverse nature of the
types and the large range in the amount of humus within the type.
3. The loss on ignition shows a considerable variation within the
type and no significant distinction between the four types.
4. The average total calcium content of the types is distinct,
though the wide range within each type minimizes the significance of
the variation in the averages.
5. With regard to magnesium, the types are neither distinct nor
are the soils within the type closely similar.
6. The average phosphorus content of the types is distinct, though
the ranges within the several types frequently overlap.
7. The total potassium results do not show the types to be distinct
nor the soils within a type closely similar.
482 University of California Publications in Agricultural Sciences [Vol. 3
Bacteriological Relations
1. The ammonifying power shows rather larger variations from
type to type than between the samples of a type.
2. The nitrogen fixation data do not show characteristic differences
for the several types.
3. Regarding nitrification as a whole there may be a greater
divergence between the samples of a type than between types. The
relative nitrification of the soil's own nitrogen varies with the type,
as does the relative nitrification of the several nitrogenous materials
added.
Pot Cultures in the Greenhouse
In addition to the effect of the probable error, the impossibility
under the conditions herein described of growing the same crops on
all the soils, during the same season of the year in the greenhouse,
prevents close comparisons between the types, or between the first and
second crops on a given soil. The comparison of several samples of a
given soil type and the comparisons of various soil types, according
to the previously outlined greenhouse methods show that :
1. Different representatives of a given type are not the same in
their ability to produce crops.
2. The arrangement of the samples of a given type according to
their fertility may or may not vary with the special crops used as the
indicators.
3. The types are distinct with respect to their fertility, considering
their average production.
Therefore it is concluded that with regard to the 24 soils of 4
types examined, all soils mapped under a given name by the Bureau
of Soils method may or may not be closely similar, depending upon
the criteria used. The greater number of the criteria show the soils
of a type to be not closely similar, and the types to be but litle differ-
entiated from each other.
In connection with the results of the author's study of the soils,
there is given an historical sketch of the development of soil classifica-
tion and mapping, also a discussion of certain of the methods em-
ployed by the Bureau of Soils of the United States Department of
Agriculture. It is pointed out that despite its defects, the work of
the Bureau of Soils is of value, and is practically the only type of soil
classification and mapping possible under the conditions imposed.
1919] Pendleton: A Studij of Soil Types 483
APPENDIX A
METHODS AND TECHNIQUE
Collection of Samples
There was difficulty in finding types that would meet the requirements of wide
distribution and of differing from one another as to series as well as texture. The
types chosen were:
Diablo clay adobe, a residual soil.
Altamont clay loam, a residual soil.
San Joaquin sandy loam, an "old valley filling" (old alluvial soil).
Hanford fine sandy loam, a recent alluvial soil.
The first task was the collection of the samples of soil for study in the labora-
tory and in the greenhouse. Of course, there were kept in mind the errors and
difficulties involved in the collection of representative samples. The selection of
the localities in which to collect samples was frequently made in consultation with
the persons who had originally mapped the areas under the Bureau of Soils.
This was done so that the soil chosen might as nearly as possible represent what
the surveyor had in mind as characteristic of the type within the area. It was to
be expected that the ideal type which one man would use as a guide as he did the
mapping in one area would not always be identical with that which another man
might use in mapping another area, despite the aid of the inspector in keeping the
ideal types of the field men as nearly alike as possible. Some of the accompanying
index maps, showing the places where the soil samples were collected, are dupli-
cates of the same locality. As the dates show, one is a portion of a less recent,
and the other of a more recent survey. In many cases the index maps have been
copied from the manuscript maps, a number of surveys in this state not yet being
published. For a discussion of the differences in these maps, see below the section
on The Criticism of the U. S. Bureau of Soils Method of Surveying.
Not only were the field men questioned about the locality, but as nearly as
possible an exact designation was obtained on the soil map itself. In the collec-
tion of some of the samples the writer had the good fortune to have the assistance
of the man or men who actually mapped the soils in question. Sometimes there
was no trouble at all in locating a typical body of the soil where a sample might
be taken. On the other hand, as in the case of the collection of the Hanford fine
sandy loam from Woodbridge (nos. 15 and 16), more than two hours were spent
in driving about, trying to find a place that seemed a typical fine sandy loam.
Experience shows that the personal equation in field work is very important and
is hard to control. 45
No special attempt was made to obtain virgin soil, for the types of soils that
had been selected for study were mainly agricultural, and most of the soils have
been at some time under cultivation, if they are not now. Also, there has been
little, if any modification of the agricultural soils by the addition of fertilizers.
Hence the small tracts of the Hanford fine sandy loam, for instance, that are still
virgin are largely non-agricultural, waste land areas, and would not illustrate the
properties of the type as a whole. Not so large a part of the San Joaquin sandy
loam is under cultivation now, though almost all of it has been farmed to grain
in the past. The two minor types studied, the Altamont clay loam and the Diablo
clay adobe, being of residual origin and occupying rolling to hilly or mountainous
land are also not very extensively farmed. The topography is the limiting factor
in most cases.
45 Fippin, E. O.. Practical Classification of Soils, Proc. Amer. Soc. Agron., vol. 3 (1911),
pp. 76-89 ; Increasing the Practical Efficiency of Soil Surveys, Proc. Amer. Soc. Agron.,
vol. 1 (1907-1909), pp. 204-06.
484 University of California Publications in Agricultural Sciences [Vol.3
The ideal way to collect a representative sample of soil for laboratory studies
is to make a number of borings scattered about the field or fields, so that the sam-
ple will approximate an average. But in the case of collecting the samples for this
study it was considered best not to attempt such a procedure, for the reason that
it was desired to have the samples for the greenhouse work and for the physical,
chemical, and bacteriological studies, come from the same lot of soil. The collec-
tion of such a large amount of soil, about 250 pounds in all, from a number of
places about the selected field would be very tedious. Hence as nearly a typical
place as possible Avas selected, close to a wagon road, in order that the samples
could be transported readily. Care was used that the location be far enough out
into the field to allow the sample to be representative of the conditions in the field.
The subsequent procedure was as follows: The selected spot was cleared of
grass or other surface material or accumulation that did not belong to the soil.
A hole was dug, usually one foot deep (the depth depending entirely upon the
nature of the surface soil and any noticeable changes toward the subsoil), and
big enough to give sufficient soil to make up the greenhouse sample of from 225
to 250 pounds. The soil was shoveled directly into tight sugar or grain sacks, no
attempt being made to mix the sample at this time. Some sacks of the soil would
contain more of the surface material, and others more of the lower portion, but a
later thorough mixing and screening at the greenhouse gave a uniform sample.
After the large sample was collected, the hole was usually dug two feet deeper,
giving a hole three feet deep. One side of this hole was made perpendicular, and
from this side the small samples were collected. The A, B, and C horizons were
marked off on this wall, and the samples collected by digging down a uniform
section of the designated portion, using a geologic pick and catching the loosened
material on a shovel. About ten pounds of soil were so collected, and placed in
clean, sterile canvas sample sacks. Care was used not to contaminate the samples,
so that the bacterial flora might remain nearly unaltered. It seemed imprac-
ticable to attempt to collect the laboratory sample under absolute sterile condi-
tions, especially since some of the deeper (B and C) samples were obtained by
means of the soil auger. When the auger was used to collect the samples from
greater depths the boring was done from the bottom of the hole made in collect-
ing the larger sample. The size of the laboratory sample required the boring of
five or six holes with the usual 1.5 inch soil auger. The laboratory sample of the
first foot, or the A sample, was always collected from the side of the large hole.
Notes regarding the sample, field condition, the place of collection, together with
photographs and marked maps are given in appendix B.
As described above, the soils were collected in separate portions from the sur-
face to the 12 inch, from the 12 to 24 inch depth, and from the 24 to 36 inch
depths where there were no abrupt or marked changes in the color, texture, or the
like, as in the Hanford fine sandy loam. But since in some cases, as most fre-
quently in the San Joaquin sandy loam, the samples do not represent the first,
second, or third foot depths, as the case might be, the term, horizon, has been
used. Horizon A indicates the surface sample, horizon B the second sample, and
horizon C the third sample.
Laboratory Preparation of Samples
The large samples were stored in the greenhouse until ready for use. The lab-
oratory samples were allowed to remain in the sacks until air dry, when they were
passed through a 2 mm. screen. This was a difficult matter, with the heavy soils,
as well as with the heavy subsoils of the San Joaquin sandy loam. Cautious use
1919 J Pendleton: A Study of Soil Types 485
of the iron mortar "was necessary to supplement the rubber pestle. 40 The samples
were thoroughly mixed after screening, when they were weighed and placed in
sterile containers — glass jars and large bottles. Precautions were taken as far
as possible to avoid contamination of the samples during this preparatory process.
The screens, mortars, scoop, and pans were flamed out between samples. Obvi-
ously contamination could not be avoided absolutely without too great a prolonga-
tion of the work.
The material not passing the 2 mm. screen was subsequently washed on the
screen, with a stream of water to remove the finer material. The residue not
passing the screen by this treatment was dried and weighed. It seemed unneces-
sary to adopt elaborate precautions, like those described by Mohr, 47 to obtain the
exact quantities.
Mechanical Analysis
The Hilgard elutriator was used for the purpose of making the mechanical
analysis of the samples (surface horizon only). For the purpose of this work
the method described by Hilgard 48 has been modified in several respects. The pre-
liminary preparation by sifting through the 2 mm. sieve in the dry state, and
through the 0.5 mm. sieve by the aid of water was used. One hundred grams was
sifted with the 0.5 mm. sieve, and the fine material plus the water was evaporated
to dryness on the water bath. The dry material was broken up and from this
the samples were weighed out for the analysis.
The samples were not disintegrated by boiling, since it was believed that such
treatment would affect the "colloid" content of the sample. Instead, the samples
were shaken with water in sterilizer bottles for three hours, similar to the treat-
ment preparatory to the mechanical analysis by the Bureau of Soils method.
However, not boiling the samples caused more work later.
The colloidal clay was removed by placing the previously shaken sample in a
large precipitating jar and stirring up with several liters of distilled water. (Dis-
tilled water was used throughout the analysis.) The quantity of water was not
important, but rather the depth of the suspension, which was 200 mm. After
allowing to stand for 24 hours the supernatant turbid water was siphoned off,
when the residue in the bottom of the jar was again stirred up with water and
the clay again allowed to settle out of a 200 mm. column. This was repeated
until the supernatant liquid contained practically no material in suspension after
standing for 24 hours. The clay suspensions were placed in large enamelware
preserving kettles, and the solutions reduced in volume by boiling. The final
evaporations were carried on over the water bath, so as to avoid too high a tem-
perature.
A large portion of the finest sediment (0.25 mm. hydraulic value) was removed
as follows : After the greatest portion of the clay had been removed by the 24
hour sedimentation and decantation, the sample was placed in a 1 liter beaker and
stirred up with sufficient water to make a 100 mm. column. After standing 6
to 8 minutes the suspended material was decanted off. This was repeated until
the supernatant solution was practically clear. The entire time for these decanta-
tions usually occupied 2.5 or 3 hours. The decanted material was allowed to stand
for 24 hours, as before, and the 200 mm. column decanted as with the original
clay suspension. This was continued until the clay was practically all removed.
46 Hilgard, Calif. Agri. Exp. Sta., Circ. 6, June, 1903.
47 Bull. Dept. Agr. Indes Neerland., no. 41, 1910.
48 Calif. Agr. Exp. Sta., Circ. 6 (1903), pp. 6-15; see also Wiley, Agricultural Analysis,
vol. 1 (1906), pp. 246-62.
486 University of California Publications in Agricultural Sciences [Vol. 3
The residue constituted the main portion of the 0.25 mm. hydraulic value sep-
arate. The residue from the 6 to 8 minute decantation was placed in the elutri-
ator, and separated by the usual method into the various sizes. Since, however,
the sample was not prepared by boiling previous to the separation of the clay, the
clay was never as thoroughly removed from the coarser particles and the finer
aggregate particles were not completely broken down. Hence when the sample
was placed in the elutriator and subjected to the violent agitation of the stirrer
an appreciable amount of clay passed off with the finest separate. Therefore,
instead of allowing the water to return to the carboy from the settling bottle,
during the running off of the finest separate, the following procedure was em-
ployed: The water was run into precipitating jars and allowed to stand for 24
hours, and the clay water was then decanted off and boiled down with the other
clay water.
A further modification of the Hilgard method was found advisable after the
change from the large elutriator tube to the small one, preparatory to running off
the coarser separates. The mechanical defects in the elutriator always allowed
for the collection of a portion of the sample in crevices where the stream of water
could not reach to carry off the particles. Hence, when the large tube was
removed, and cleaned, there was found an appreciable amount of the finer sedi-
ments that had not passed over. These were all added to the small tube of the
elutriator, and the additional material of the smaller sizes run off, using an hour
or so for each size. This seemed a better method than the separation of such
sediments by the beaker method, as was done by Dr. Loughridge.
The separates, after decanting most of the water, were dried first on the water
bath and later in the drying oven at 100°C-110°C and weighed. All of the deter-
minations were made on the water free basis. 49
Additional Physical Determinations
Upon the surface or A horizon samples of the 24 soils considered in this study
additional physical determinations were made by the Division of Soil Technology,
through the courtesy of Professor Charles F. Shaw. These determinations were
of the mechanical analysis by the Bureau of Soils method, 50 of the moisture equiva-
lent by the Briggs and McLane method, 51 and of the hygroscopic coefficient accord-
ing to Hilgard 's method. 52
Chemical Methods
At first the chemical work was based upon the ' ' strong acid extraction ' J
method, so well known through the work of Dr. Hilgard. 53 There are some very
pertinent objections, as well as advantages, to the method of acid extraction for
the purpose of comparing soils among themselves. 54
in the analysis 2.5 gram samples, air dry, were used throughout. The acid
extraction results are not included in this paper.
49 The writer wishes to emphasize the tedium of the elutriator process, and to advise
Strongly against the use of the apparatus for the comparison of the soils as to texture. The
elutriator is excellent from a theoretical point of view, but the results do not at all warrant
the extravagant use of time in the laboratory that the apparatus requires.
""('. 8. Bur. Soils, Bull. 84, 1912.
"'' Ibid., Bull. 45, 1907; Proc. Amer. Soc. Agron., vol. 2 (1910), pp. 138-47.
02 Calif. Agr. Exp. Sta., Circ. 6 (1903), p. 17; Soils, pp. 197-99.
"Calif. Agr. Kxp. Sta., Circ. 6 (1903), pp. 16ff; Soils, pp. 340ff.
:A Sec Ilissink, Intern. Mitt, fur Bodenkunde, vol. 5 (1915), no. 1.
1919] Pendleton: A Study of Soil Types 487
The sodium peroxide fusion method 55 was carried out on the two larger series
of soils, the Hanford and the San Joaquin. The elements sought were phosphorus,
calcium, and magnesium. Five gram samples, air dry, were used throughout.
The general method of analysis, as set forth by Hopkins, Avas employed, though
there were a number of refinements used to increase the accuracy of the results.
As such might be mentioned the double precipitation of the iron, aluminum, and
phosphorus.
Phosphorus was determined volumetrically, according to the method of Hib-
bard. 56
Total nitrogen was determined by the modified Gunning-Kjeldahl method,
using ten gram samples.
Loss on ignition was determined upon the 10 gram, air dry samples that were
used for the determination of the hygroscopic moisture of the samples used in
the chemical analysis. The soils were ignited in a muffle furnace to constant
weight.
Humus was determined by the Grandeau-Hilgard method, 57 using 10 gram
samples, air dry.
Potassium was determined by the J. Lawrence Smith method, using one gram
samples.
Bacteriological Methods
The only bacteriological methods employed were the determination by the tum-
bler or beaker method of the ammonifying, the nitrifying, and the nitrogen fixing
powers of the soils. 58 All cultures were run in duplicate.
Ammonification tests were made using 50 grams of soil and 2 grams (4%) of
dried blood. The checks were distilled at once, and the cultures kept in the incu-
bator at 24°C-30°C for one week. (The incubator thermostat was unsatisfactory
in its action, hence the variation in the temperature.)
The nitrifying power of the soil was tested as regards the soil's own nitrogen,
dried blood, cottonseed meal, and ammonium sulfate. In the Diablo clay adobe
and the Altamont clay loam 50 grams of soil were used, to which was added 1
gram (2%) of dried blood, or of cottonseed meal, or 0.1 gram (0.2%) of am-
monium sulfate. In the case of the San Joaquin sandy loam 50 grams of soil were
used, together with 1 gram (2%) of dried blood or of cottonseed meal, or 0.2 gram
(0.4%) of ammonium sulfate. In the series run on the Hanford fine sandy loam
100 grams of soil were used, to which were added 1 gram (1%) of dried blood or
of cottonseed meal or 0.2 gram (0.2%) of ammonium sulfate. It is to be regret-
ted that the several series could not all be run on exactly the same basis as the
Hanford series. But the small amount of stock soils of the samples of the earlier
series precluded the use of larger original samples, not to speak of the impossi-
bility of repeating these series. The cultures were incubated for four weeks at
24°C-30°C. At the end of this period the cultures were dried in the oven at about
90 °C and the nitrate content determined by the phenoldisulfonic acid method
according to the modifications of Lipman and Sharp. 59
Nitrogen fixation. For this determination uniform quantities of soil were
used throughout — 50 grams, to which was added 1 gram of mannite. These cul-
55 Hopkins, Soil Fertility and Permanent Agriculture, pp. 630-33; Hopkins and Pettit,
Soil Fertility Laboratory Manual (Boston, Ginn, 1910), pp. 42-45.
56 Jour. Ind. Eng. Chem., vol. 5, pp. 993-1009.
"Calif. Agr. Exp. Sta., Circ. 6 (1903), p. 21.
58 Burgess, P. S., Soil Bacteriology Laboratory Manual, Easton, Pa., The Chemical Pub-
lishing Co., 1914.
59 Univ. Calif. Publ. Agr. Sci., vol. 1 (1912), pp. 21-37.
488 University of California Publications in Agricultural Sciences [Vol.3
tures were incubated for four weeks at 24°C-30°C, at the end of which time bac-
terial action was stopped by drying in the oven for 24 hours. Subsequently, the
samples were broken up in a mortar, and 10 grams weighed out for the determina-
tion of the total nitrogen.
Pot Cultures in the Greenhouse
The large samples of the surface foot of soil were stored in the greenhouse
until used. The preparation of the samples was in most cases as follows: The
sample was placed on a large table and screened through a quarter inch sieve.
This treatment of screening was attempted with the Diablo clay adobe and the
Altamont clay loam, but was abandoned as practically hopeless. The samples of
these two types had been collected in the late summer, when the ground was very
hard and dry, hence the clods defied any efforts to break them up. As an alterna-
tive the samples were as thoroughly mixed as possible and weighed out into the
pots. Several waterings during a week, together with carefully breaking up the
lumps by hand, rendered the soils finely divided enough to permit the planting of
the seeds. The Hanford and San Joaquin types were readily screened.
All the soils were weighed out into nine inch flower pots. In most cases the
pots had been previously paraffined. Care was taken to clean the pots thor-
oughly, as far as surface material was concerned; many of the pots were scrubbed
with a brush and water. All previously used pots were examined to exclude the
use of such as had formerly been used for soils containing high percentages of
soluble salts, but such examination was not always successful in eliminating the
undesirable pots, as was afterwards evident. In the Diablo, Altamont, and Han-
ford soils the quantity of soil used was five kilos per pot. In the San Joaquin
soils six kilos were used.
Enough soil was collected to fill eighteen pots. This would allow for the
arrangement of six sets of triplicates of every sample; and the planting of a dif-
ferent crop in each of the sets would allow for the growing simultaneously of six
different crops on every soil. For example, there were placed together in the
greenhouse and considered as a unit in the culture work the series of the Diablo
clay adobe, including three pots of the sample taken from San Juan Capistrano,
three from that taken near Los Angeles, three from that of the San Fernando
valley, and lastly three from the sample taken in the Danville region. This group
of pots was planted to oats, barley, bur clover, or any one other crop. The pots
were kept together in the greenhouse, that the conditions for each one in the set
would be as nearly uniform as possible, for even a slightly different location in
the greenhouse was found to affect the crop appreciably. The other five sets of
pots were similarly treated. No fertilizing materials were added to any of the
soils. All were used in their normal condition. The aim was to compare the crop
producing power of the representatives of a given type of soil from various
localities.
Several crops were grown, as the desire was to get a series of plants that
would grow well under greenhouse conditions, and act as indicators. It was
known that barley was about the best crop to use, but supplementary plants were
desired. Barley, wheat, oats, rye, millet, milo, cowpeas (black eye beans), soy
beans, beans (small white), bur clover (Mcdicago denticulata) , sweet clover (Meli-
lotus indica), and oats and bur clover in combination were tried. Some were
a marked success under greenhouse conditions, and others were practically total
failures; the better crops were given by barley, soy beans, bur clover, and millet.
Sweet clover gives excellent results. This wide range of varieties of plants was
1919] Pendleton: A Study of Soil Types 489
necessary because of the fact that it was desired to grow two crops a year on the
soils. The winter crops will not do well in summer, and vice versa, even though
the summers in Berkeley are relatively cool, and though the greenhouse was
whitewashed during the summer months.
The seed was obtained in most cases from the Division of Agronomy of the
Department of Agriculture of the University of California. Such varieties as
were not available from this source were obtained from the commercial seed
houses in San Francisco.
Usually the seed was planted directly in the pots, using sufficient seed to be
sure that enough would germinate and grow to give the desired number of plants
per pot, usually six. After the plants were well established, and before there was
any crowding in the pots, the plants were thinned. In some cases an insufficient
number of plants germinated to give the desired number per pot. Difficulty was
found in getting the soy beans and cow T peas to germinate, especially in the
heavier soils. This was overcome by sprouting the seeds in an incubator and
planting them when the radicle was half an inch long or more. An excellent stand
was thus obtained.
Xo actual measurements of the height of the plants, or the length of leaves
were made in the greenhouse work. But photographs were taken, and in these
photographs the attempt was made to secure representative records of the entire
series, without photographing the crop in every pot. The usual procedure in the
Altamont and Diablo series was to photograph two pots out of each set of tripli-
cates, an attempt being made to select average, representative pots. In the large
Hanford series one representative pot of each set of triplicates in each crop
series was photographed, and three representative sets of triplicates were also
photographed. Thus some of the pots appear twice, and allow of comparisons.
If any doubt be entertained as to the relative weights of the crops in the pots
photographed as compared with those not so recorded, the relative weights of the
crops may be easily obtained by referring to the tables of dry weights. In prac-
tically every case the pot label can be read from the photograph. The method of
labeling is exemplified as follows:
6 Soil sample no. 6 (Diablo clay adobe from Danville).
W Wheat, first crop.
2 Pot 2 of the triplicate set first planted to wheat.
CP Cowpeas, second crop.
During the growth of the crops, notes were taken as to the relative growths and
the general conditions of the plants.
When the crop had ceased growing it was harvested, whether or not it was
mature in the sense of having set and developed seed. The plants from a given
pot were put in a paper bag, labeled, and placed in the drying oven for 2! hours.
The plants were weighed when dry and cool. If any mature seed was produced
it was weighed separately.
Between the first and second crops the soil was allowed to rest from two to
three weeks or longer. Each pot was emptied and the soil passed through a
quarter inch screen before replacing in the pot. This broke up the lumps and
removed most of the roots. The roots were not saved. The weight of the roots
would have been interesting, but their recovery, especially from the heavy soils,
would have involved careful washing, and the loss of much of the soil. It was
thought that some washing would be necessary, even in the Hanford series, in
order that the resulting figures might be at all accurate.
490 University of California Publications in Agricultural Sciences [Vol. 3
APPENDIX B
SOIL SAMPLE LOCATIONS
Field Notes on the Soil Samples Collected
No. 1 — Diablo Clay Adobe
Location: A little over a mile east of San Juan Capistrano, Orange County. On
the lower slopes of the hills to the south of San Juan Creek. Sample sta-
tion is on a little shoulder running northwest, between Mr. Echenique's
house and the fence following the road to Prima Deshecka Canada. Ap'
proximately one-quarter mile from the above house.
Soil: 0-12 inches — Dark gray adobe; much cracked.
12-36 inches — Soil becomes gradually lighter in color, approaching a light
bluish gray mottled Avith brown.
36 inches — The subsoil becomes a silty clay loam in the lower depths.
History: The field was pastured up to and including 1906. From 1907 to date
the field has been annually planted to barley. Data from Mr. Echenique,
the owner. Sample collected August 19, 1917.
Depths of horizons:
1-A 0-12 inches. 1-B 12-24 inches. 1-C 24-36 inches.
No. 2 — Diablo Clay Adobe
Location: One and three-quarter miles east of southeast of Eastlake Park, Los
Angeles. Station is 0.7 mile by secondary road south of Pacific Electric
railroad crossing, and 1.2 miles southeast of the Southern Pacific railroad
crossing. Station is about 150 feet up the hill to the west of the road, in
grain field, and 75 feet south of a 10 or 12 year old eucalyptus grove.
The road, going south, emerges from the grove, and is then flanked by pep-
per trees.
Soil: 0-12 inches — Dark gray to almost black, but with a shade of brown rather
than a bluish gray.
12-24 inches — Dark grayish brown clay adobe, becoming a little lighter with
depth.
24-36 inches — Dark brown with soft, whitish fragments. Fragments probably
the partially weathered parent rock, though no outcrops of the rock were
seen in the vicinity. Previous to the collection of the sample, Mr. E. C.
Eckman, who mapped the area as the Bureau of Soils representative, said
in substance: "We have no good Diablo in the area; the body I am
directing you to is as good as any, but it is pretty brown. ' '
History: Property owned by Mr. Huntington. Farmed to grain the past 2
years; pasture previously. Data from the son of the tenant. Sample col-
lected August 20, 1915.
Depths of horizons:
2-A 0-12 inches. 2-B 12-24 inches. 2-C 24-36 inches.
No. 3 — Altamont Clay Loam
Location: 1.4 miles southeast of Walnut, Los Angeles County, on the shoulder of
a low hill, about 200 feet east of the wagon road running south through
the hills. The station was selected so that the texture was about right,
for in a very short distance there were variations from a heavy dark clay
loam or clay adobe to the light clay loams.
1919] Pendleton: A Study of Soil Types 491
Soil: 0-36 inches — A medium textured brown friable clay loam. The soil column
throughout was more or less filled with small soft whitish fragments, por-
tions of the parent rock.
36 inches — The weathered parent rock was encountered.
History : A. T. Currier, owner. The field is in pasture, and has not been culti-
vated for forty years, to the knowledge of the ranch foreman. The soil is
probably virgin. Sample collected August 20, 1915.
Depths of horizons:
3-A 0-12 inches. 3-B 12-24 inches. 3-C 24-36 inches.
No. 4 — Altamont Clay Loam
Location: On a hillside a few feet above the Cahuenga Pass (Burbank road),
near Oak Crest, Los Angeles County. Just a few feet from the U. S.
Bureau of Soils station for the type in the San Fernando area. (For map,
see the map under sample no. 25.)
Soil: 0-14 inches — A dark brown clay loam.
14-36 inches — A yellowish brown loam, grading into the weathered, thin bed-
ded shales at about 36 inches.
History : Roadside, above the big cut on the road, probably never tilled. The sur-
face is not so steep but that it could be well tilled; some of the soil in
the immediate vicinity is cultivated to grain. Sample collected August 21,
1915.
Depths of horizons:
4-A 0-12 inches. 4-B 12-24 inches. 4-C 24-36 inches.
No. 5 — Diablo Clay Adobe
Location: About % a mile north of Calabasas, San Fernando Valley, Los Angeles
County. The station is some distance up the hill to the west of the road
running north from the Calabasas store. The sample was collected near
the top of the hill, to the northeast of the oak tree.
Soil: A dark gray to black typical clay adobe. Distinctly heavy. Digging was
very difficult, the soil coming up in large, very hard clods. The soil was of
about the same color and texture down to the bedrock at 26 inches. The
bedrock is a heavy claystone or shale.
History : John Grant, Calabasas P. O., owner. The land has been dry farmed
to grain. Presumably there had been no additions of fertilizing materials
to the soil. Sample collected August 21, 1915.
Depths of horizons:
5-A 0-14 inches. 5-B 14-26 inches. 26 inches. Parent rock.
No. 6 — Diablo Clay Adobe
Location: In Contra Costa County, % mile west of Tassajero; 6 miles east
and a little south of Danville. Station about 150 feet up the hill to the
south of the road, that is, about one-third of the way up the hill.
Soil: 0-34 inches — A black or dark gray clay adobe, moist at 10 inches.
34-72 inches — A dark grayish brown subsoil, becoming lighter below the third
foot. No bedrock within the 6 foot section, nor was there any sign of any
outcrop in the vicinity. The slope of the hill moderate, the exposure
north. The sample was collected with the assistance of Mr. L. C. Holmes
and Mr. E. C. Eckman, both of the U. S. Bureau of Soils. They pro-
nounced the station typical.
492 University of California Publications in Agricultural Sciences [Vol. 3
History: Property owned by J. J. Johnson. The field has been farmed to grain
for probably 60 years. Formerly the rotation was pasture one year, and
grain one year; now the practice is grain two years, and pasture one year.
Sample collected September 2, 1915.
Depths of horizons:
6-A 0-12 inches. 6-B 12-24 inches. 6-C 24-36 inches.
No. 7 — Altamont Clay Loam
Location: On the Mission Pass road, a little less than 2 miles south and a little
west of Sunol, Alameda County. About 100 feet above the road, between
wooden electric power poles nos. 92/30 and 92/31.
Soil: 0-34 inches — A medium brown clay loam, considered typical by Mr. L. C.
Holmes and Mr. E. C. Eckman of the U. S. Bureau of Soils. There were
slight changes in texture.
34 inches — A stiff clay horizon.
Inspection of a deep cut on the roadside near the location of the sample
station showed that at 6 feet and deeper there existed a heavy reddish clay.
In the immediate locality the road sections showed that the parent rock
was deeper than the 6 foot section. The slope of the land at the sample
station was quite steep.
History: Tom Burns, Irvington, owner. Field has been in pasture for the past 3
years at least, and probably for a much longer time. Sample collected
September 2, 1915.
Depths of horizons:
7-A 0-12 inches. 7-B 12-24 inches. 7-C 24-36 inches.
No. 10 — San Joaquin Sandy Loam
Location: North Sacramento, Sacramento County; }4 mi le east of tile factory,
across the road; opposite poles 57/32 and 57/33, 75 feet southeast from the
State Highway.
Soil: 0-26 inches — A brownish red sandy loam, slightly hog wallowed, and very
slightly rolling.
26-36 inches — A sandy clay loam.
36 inches — A hard hardpan.
History : Owner not known, the district now being subdivided, the property being a
portion of the old ' ' Hagan Grant. ' ' A near-by resident gave the following
information : ' ' The land has not been cultivated for the past 15 years or
more. The land is said to have been farmed to grain at one time for a few
years, but the ' soil is too light for wheat, it grows nothing but filaree. ' ' '
The principal use has been for cattle and sheep pasture. Sample collected
March 28, 1916.
Depths of horizons:
10-A 0-12 inches. 10-B 12-24 inches. 10-C 24-36 inches.
No. 11 — San Joaquin Sandy Loam
Location : Four miles west of Lincoln, Placer County, at the l ' Road Corners, ' '
in the southeast field, 10 feet east of the west fence and 60 feet south of
the north fence.
1919J Pendleton: A Study of Soil Types 493
Soil: A gently hog wallowed, sandy loam, with some deeper depressions, prob-
ably stream channels. Sample slightly gravelly.
0-12 inches — Brownish or reddish brown sandy loam.
12-17 inches — Sandy clay loam or clay, color the same.
17-23 inches — A stiff reddish brown clay.
23 inches — A hard hardpan.
History: Mr. Frank Dowd, owner. The land has been planted to wheat for the
past 20 or 25 years; previous to that time it was used for pasture. Six
to 10 or 12 bushels of wheat, and 8 to 20 bushels of barley is the production
of this soil in the locality. The soil is usually fallowed on alternate years.
Land held at from $30 to $50 per acre. Sample collected March 28, 1916.
Depths of horizons:
11-A 0-11 inches. 11-B 11-17 inches. 11-C 17-23 inches.
No. 12 — San Joaquin Sandy Loam
Location: About 6 miles west of Wheatland, Sutter County. Near a road corner,
in a little swale west of a knoll, 15 feet east of the westerly fence of field,
and 150 feet south of the north line of the westerly road.
Soil: Texture slightly heavy, and barely enough sand for a sandy loam, but the
best found for several miles. Color brownish red, the same throughout the
entire depth.
0-18 inches — Light, fine textured, sandy loam.
18-31 inches — Heavy sandy clay loam, running into a stiff clay.
31 inches — Hardpan, sandy and somewhat soft. The ground was very
moist at this time.
History: Very evidently pasture for sheep and cattle. No signs of having been
cultivated for several years, at least. The cover is of a number of low
annuals — Orthocarpus, Trifolium, Centaurea, and others. Sample collected
March 29, 1916.
Depths of horizons:
12- A 0-12 inches. 12-B 12-18 inches. 12-C 18-31 inches.
No. 13 — San Joaquin Sandy Loam
Location: Three and three-quarters miles east of Elk Grove, Sacramento County.
On the Sheldon road, about 30 feet northwest from the fence on the north
side of the road. About 200 feet southwest from where a house formerly
stood.
Soil: A reddish brown sandy loam, approaching a loam; becoming redder in
color with increasing depth.
0-14 inches — Heavy sandy loam.
14-22 inches — Clay loam.
22-29 inches — Heavy clay loam.
29 inches — Compact hardpan.
History: Wackman Brothers, Elk Grove, owners. The land has not been plowed
or farmed for at least 15 years. The land is held at about $50 per acre.
Sample collected March 30, 1916.
Depths of horizons:
13-A 0-12 inches. 13-B 12-22 inches. 13-C 22-29 inches.
494 University of California Publications in Agricultural Sciences [Vol. 3
No. 14 — Hanford Fine Sandy Loam
Location: One mile southeast of the Sheldon road, 3^ miles east of Elk Grove,
Sacramento County. On the southwest side of the secondary road, in al-
falfa field, about 25 feet from the fence. Station on a little rise.
Soil: 0-11 inches — A medium brown micaceous heavy fine sandy loam.
11-24 inches — A dark gray to black fine sandy loam, grading into the fol-
lowing.
24-36 inches — Brown fine sandy loam. Water table at 32 inches.
History: Mrs. A. C. Freeman, Elk Grove, owner. Land planted to alfalfa. Good
growth. No irrigation. Willows as well as alders and river ash along the
sloughs. Many scattering valley oaks. The land is subject to overflow
from the Cosumnes Eiver, as it lies low in the river bottom, and shallow
stream channels and sloughs are frequent. Sample collected March 30, 1916.
Depths of horizons:
14-A 0-12 inches. 14-B 12-24 inches. 14-C 24-36 inches.
No. 15 — Hanford Fine Sandy Loam
Location: North of Woodbridge, San Joaquin County, along the State Highway,
less than *4 mile south of the road running westerly from Acampo to the
highway. Station in a vineyard, with almond trees along the roadside, 20
feet northeast of "change telephone pole," 200 feet north of pine tree
at the gateway on the opposite side of the highway. (For map, see under
sample 16.)
Soil: Texture a rather coarse fine sandy loam; it was hard to find a good fine
sandy loam. Color when moist was a medium brown throughout the 3 foot
section ; the field color was a light grayish brown.
History: Mike Nolan estate, owner. The vineyard is of Tokay grapes, 10 to 12
years old. The land is held at $300 to $400 per acre. It is said to be a
losing game to farm this land to grapes at this valuation. Sample col-
lected March 30, 1916.
Depths of horizons:
15-A 0-12 inches. 15-B 12-24 inches. 15-C 24-36 inches.
No. 16 — Hanford Fine Sandy Loam
Location : Along the road north of Woodbridge, San Joaquin County. In a young
pear orchard about 65 feet west of the highway, and about 95 feet north
of the north abutments of the bridge over Mokelumne Eiver.
Soil: A medium brown fine sandy loam, similar throughout the soil column of
three feet. This soil is of the recent, flood-plain phase of the type, though
this station is not known to have been under water for a number of years,
at least. There is only a comparatively narrow shelf of this phase between
the older, higher phase, and the river.
History: A. Pen-in, Woodbridge, owner. The land had always been in brush
and pasture until it was cleared and planted to pears in 1911. Value
about $500 per acre. Sample collected March 30. 1916.
Depths of horizons:
16-A 0-12 inches. 16-B 12-24 inches. 16-C 24-36 inches.
1919] Pendleton: A Study of Soil Types 495
No. 17 — San Joaquin Sandy Loam
Location : A short distance south of the east and west road that runs east to
Thalheim, San Joaquin County. The station was on a slight knoll 75 feet
south of a canal, and the same distance east of the secondary road running
north and south; not far from a vacant barn.
Soil: 0-12 inches — Eeddish brown.
12-21 inches — Slightly redder.
21 inches — Hardpan.
The surface had the characteristic hog wallows, and the usual scant vegeta-
tion of grasses and herbs, "filaree" being abundant; yet all vegetation
was more abundant than that in pastured fields.
History : Rev. Frank Hoffman, Acampo, owner. Apparently, the land has not
been cultivated in recent years. Sample collected March 31, 1915.
Depths of horizons:
17-A 0-12 inches. 17-B 12-21 inches.
No. 18 — San Joaquin Sandy Loam
Location : Two and one-half miles northwest of Madera, Madera County. Along-
State Highway, 75 to 100 feet southwest of the paved road, at telephone
pole 92/29; across the highway from the driveway to the house.
Soil: 0-5 inches — A light reddish brown sandy loam. A noticeable plow pan at
5 inches.
5-21 inches — A light brownish red sandy loam, becoming heavier below.
21-30 inches — Quite compact heavy sandy loam.
30 inches and deeper — A very compact hardpan.
Topography very gently rolling, hog wallows well developed, though consider-
ably degraded by cultivation. Barley grain not growing well in the lower
spots.
History: Cropped for probably 20 years to grains; barley at present. Land used
for pasture previous to grain farming. A good yield is 8 sacks, varying
from that down to little or nothing. Miller and Lux, owners. Sample col-
lected April 11, 1916.
Depths of horizons:
18-A 0-12 inches. 18-B 12-24 inches. 18-C 24-30 inches.
No. 19 — Hanford Fine Sandy Loam
Location: Eight miles east of Waterford, Stanislaus County, near Robert's Ferry
bridge. About 75 feet west of the road that runs south from the bridge
onto the bluff. About 450 feet north of the driveway to the Sawyer place.
Twenty-five feet inside of the fence, in the alfalfa field.
Soil: Medium brown fine sandy loam; a good brown color when moist. Texture
somewhat variable, some rounded gravels up to the size of a hen's egg.
Topography undulating, and more or less terraced, due to the old stream
channels.
History: G. H. Sawyer, Waterford, owner. Alfalfa planted in 1915, looks well.
Land previously planted to barley and wheat, with a production about as
follows: barley, 14 sacks is considered good; wheat with 12 sacks is good,
with 6 sacks a low average. Value of the land as recently determined in
court, in a case of flood damage by a canal break, is $100 per acre. On an
adjoining piece of land young walnut trees are doing very well. Sample
collected April 11, 1916.
Depths of horizons:
19-A 0-12 inches. 19-B 12-24 inches. 19-C 24-36 inches.
496 University of California Publications in Agricultural Sciences [Vol. 3
No. 20 — Han ford Fine Sandy Loam
Location : Near Hopeton, Merced County, 14 miles north of Merced. Less than
14 mile north from the road corners, 15 feet east of the east fence of the
road, and 150 feet south of irrigating ditch.
Soil: A good medium brown fine sandy loam. The color is especially good when
the soil is moist. The topography is slightly uneven because of the old
stream channels. Going north along the road from the cross roads the
soil is quite gravelly at first, but the texture gradually becomes heavier,
with less gravel. At the sample station the texture is a rather heavy fine
sandy loam.
History: J. G. Euddle, Snelling, owner. The field is planted to alfalfa, as are
most of the Hanford soils in the locality. The land is not subject to
overflow. Sample collected April 13, 1916.
Depths of horizons:
20-A 0-12 inches. 20-B 12-24 inches. 20-C 24-36 inches.
No. 21 — San Joaquin Sandy Loam
Location: Near Nairn Station, Merced County. About 14 mile west of the rail-
road, 50 feet north of the private ranch road, and 120 feet east of the field
gate across the road. About 4 miles northwest of Merced.
Soil: A good brownish red San Joaquin color. Texture a sandy loam, grading
into a clay loam or clay at about 24 inches.
Depths of horizons:
24-27 inches — A heavy clay.
27 inches — Hardpan.
The same was taken from near the top of one of the hog wallow elevations.
The topography is gently rolling.
History: F. W. Henderson, Merced, owner. At the present time the land is used
as pasture. It has been plowed at some time in the past. The present
growth of wild herbage {Lepidium, small grasses, Cryptanthe, etc.) is
meager. Sample collected April 13, 1916.
Depths of horizons:
21-A 0-12 inches. 21-B 12-24 inches. 21-C 24-27 inches.
No. 22 — Hanford Fine Sandy Loam
Location: A short distance north of Basset, Los Angeles County, on the main
road north from Basset station. The sample was collected in a walnut
grove 100 feet east of the road and 250 feet south of the driveway to the
ranch house.
Soil: A good medium brown when moist, and a light grayish brown when dry.
Mr. L. C. Holmes, of the U. S. Bureau of Soils, described the soil at the
time of collection as being "all a little browner, and with a little more
color than a good Hanford. ' ? There was a very slight color change at
about a foot, the soil below was grayer. Texture a good fine sandy loam,
with practically no change in the 3 foot column. Topography smooth.
The texture varies quite rapidly from place to place in the field. Some
big washes of typical intermittent streams are found not far to the north
and west.
1919] Pendleton: A Study of Soil Types .497
History: C. N. Basset, of Basset and Nebeker, Santa Monica, owner. The land
is planted to walnuts, and the trees are about 10 years old. They are
doing well, some replants are found. The trees are irrigated. Sample col-
lected May 22, 1916.
Depths of horizons:
22-A 0-12 inches. 22-B 12-24 inches. 22-C 24-36 inches.
No. 23 — Hanford Fine Sandy Loam
Location: South and west of the town of Anaheim, Orange County. Within a
radius of 20 feet of where the official Bureau of Soils sample was taken.
Thirty feet east of side road, and 100 feet north of main east and west road.
Soil: Brown fine sandy loam, possibly a little more silty than no. 22, but not
heavy enough for a heavy fine sandy loam. Dry field color a light, grayish
brown. Topography smooth, no stream channels visible. Irrigation in fur-
rows. Soil similar to about 62 inches, a little more grayish at 18 inches,
the change being gradual. At 62 inches a gray clean sand, or fine sand,
was found.
History: S. J. Luhring, R. F. D. no. 4, owner. The field was planted to Valencia
oranges in 1913 ; previously to grapes and miscellaneous crops. Sample
collected May 23, 1916.
Depths of horizons:
23-A 0-12 inches. 23-B 12-24 inches. 23-C 24-36 inches.
No. 24 — Hanford Fine Sandy Loam
Location: Southeast of the center of Los Angeles, half way from Magnolia Ave-
nue on Fruitland Road, to Salt Lake Railroad on the east. South side of
the road about 60 feet from center, in edge of corn field. Just across
road from east end of east cypress trees.
Soil : A medium brown fine sandy loam when moist ; color in the field is a grayish
brown. Micaceous. Topography level, no stream channels seen nearby.
Color of body variable. Sample location in the browner phase. Toward
south and east along the railroad and Arcadia Avenue the color is much
grayer, and even black when moist. Texture within the body is very vari-
able, though always within the fine sandy loam group.
0-36 inches — Fine sandy loam, grayer below.
36-37 inches — Layer of grayish sand and fine sand.
37-72 inches — Fine sandy loam, heavier in streaks.
History : C. D. Templeman, R. F. D. no. 2, Box 178, Los Angeles, owner. Land
has been in truck for 10 or 12 years. Only fertilizer, barnyard manure.
Sample collected May 24, 1916.
Depths of horizons:
24-A 0-12 inches. 24-B 12-24 inches. 24-C 24-36 inches.
No. 25 — Hanford Fine Sandy Loam
Location: Near Van Nuys, Los Angeles County; near official sample station.
Seventy-five feet west of center of road, between fourth and fifth rows of
apricot trees north from boundary.
498 University of California Tuolications in Agricultural Sciences [Vol. 3
Soil: A good medium brown fine sandy loam; the field color a grayish brown.
The texture uniform throughout the 3 foot section, with a little gravel occa-
sionally. Also the texture is variable to about the usual degree, in the
field distribution. The color is slightly lighter at about 2 feet and below
throughout the C feet, with a little variation in an increasing amount of
coarser sands.
History: Chase, Eiverside, owner (?). Planted to apricots, 2 years old. Inter-
planted to melons. Sample collected May 24, 1916.
Depths of horizons:
25-A 0-12 inches. 25-B 12-24 inches. 25-C 24-36 inches.
No. 26 — San Joaquin Sandy Loam
Location: On the high bluffs about iy± miles southeast of Del Mar station, San
Diego County, close to the road that runs back along the main ridge. About
50 feet north of the road where it swings south to get around the head of
the big arroyo from the north.
Soil: A brownish red sandy loam. Surface covered with a moderate growth of
the low chapparal common to these exposed ridges. Soil heavily laden with
iron concretions. Surface has the usual hog wallows characteristic of the
San Joaquin series.
0- 6 inches — Eeddish brown sandy loam, many concretions. Dry.
j6— 13 inches — Clay (sandy), reddish in cracks, and bluish inside of lumps and
where not weathered.
13-22 inches — Clay, mostly bluish gray.
22-38 inches — Boring very difficult, due to the heavy nature of the clayey
moist material. Color bluish.
About 40 inches — Hardpan. Very compact.
History : Probably never farmed. Recently streets cleared, and an attempt made
to sell lots for building. Value for agriculture — none without irrigation.
Sample collected May 25, 1916.
Depths of horizons:
26-A 0-6 inches. 26-B 6-13 inches. 26-C 13-22 inches.
UNIV. CALIF. PUBL. AGR, SCI. VOL. 3
[PENDLETON] PLATE 43
A general view in the greenhouse, where all the pot culture work was carried
on. The entire right hand bench was devoted to this study, also half again as
much space not visible in the print.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 44
Diablo Clay Adobe — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Oats and bur elover. Left to right — Soil 1, pot 1; soil 2, pot 2;
soil 5, pot 1 ; soil 6, pot 3.
Diablo Clay Adobe — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Oats. Left to right— Soil 1, pot 1; soil 2, pot 3; soil 5, pot 2; soil 6,
pot 2.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON ] PLATE 45
Diablo Clay Adobe — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Bur clover. Left to right — Soil 1, pot 1; soil 1, pot 2; soil 1, pot 3.
Diablo Clay Adobe — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Bur clover. Left to right— Soil 2, pot 1; soil 2, pot 2; soil 2, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDlLETON ] PLATE 46
%
1S& >W^v
W&H
%il
.* : : ; f
Diablo Clay Adobe — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Bnr clover. Left to right — Soil 5, pot 1; soil 5, pot 2; soil 5, pot 3.
m
Diablo Clay Adobe — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Bur clover. Left to right— Soil 6, pot lj soil 6, pot 2; soil 6, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON ] PLATE 47
Diablo Clay Adobe — First Crop
Pots of same and different representatives of a given soil type compared.
Bur clover. Left to right — Soil 1, pot 1; soil 2, pot 2; soil 5, pot 2; soil 6,
pot 1.
UNIV. CALIF. PUBL. AGR. SCI. VOL, 3
[PENDLETON] PLATE 48
t
Diablo Clay Adobe — Second Crop
Pots of same and different representatives of a given soil type compared.
Dwarf milo («) following oats. Left to right — Soil 1, pot 2; soil 1,
Fig. 1.
pot 3; soil 2, pot 1 ; soil 2, pot 3; soil 5
pot 3.
pot 1 ; soil 5, pot 3; soil 6, pot 2; soil 6,
•
Diablo Clay Adobe — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Dwarf milo (b) following oats and bur clover. Left to right — Soil 1,
pot 1; soil 1, pot 3; soil 2, pot 1; soil 2, pot 3; soil
pot 1 ; soil 6, pot 3.
5, pot 1; soil 5, pot 3; soil 6,
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON 1 PLATE 49
Diablo Clay Adobe — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Cowpeas, following wheat. Left to right — Soil 1, pot 1 ; soil 1, pot 2;
soil 2 pot 1 ; soil 2, pot 2; soil 5, pot 1 ; soil 5, pot 2; soil (i, pot 2; soil <i, pot 3.
Diablo Clay Adobe — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Soy beans, following barley. Left to right — Soil 1, pot 1; soil 1,
pot 2; soil 2, pot 1; soil 2, pot 3; soil 5, pot 1; soil 5, pot 2; soil 6, pot 1; soil 6,
pot 2.
UNIV. CALIF. FUBL. AGR. SCI. VOL,
[ PENDLETON ] PLATE 50
Altamont Clay Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Cowpeas B, following barley. Left to right — Soil 3, pot 1 ; soil 3, pot-
soil 4, pot 1; soil 4, pot 3; soil 7, pot 1; soil 7, pot 3.
UNiV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 51
Altamont Clay Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Soy beans A, following oats. Left to right — Soil 3, pot 1; soil 3,
pot 2; soil 4, pot 2; soil 4, pot 3; soil 7, pot 2; soil 7, pot 3.
Altamont Clay Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Soy beans B, following Phaseolus. Left to right — Soil 3, pot 2
soil 3, pot 3; soil 4, pot 1; soil 4, pot 2; soil 7, pot 1; soil 7, pot 2.
UNIV. CALIF. PUBL. AGR. SCI. VOL.
[ PENDLETON ] PLATE 52
Altamont Clay Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Dwarf milo A, following wheat. Left to right — Soil 3, pot 2 ; soil 3,
pot 3; soil 4, pot 1; soil 4, pot 3; soil 7, pot 1; soil 7, pot 3.
Altamont Clay Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Dwarf milo A, following bur clover. Left to right — Soil 3, pot 1 ;
soil 3, pot 2; soil 4, pot 1; soil 4, pot 3; soil 7, pot 1 ; soil 7, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 53
Haxford Fine Sandy Loam — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Dwarf milo A. Left to right — Soil 14, pot 2; soil 15, pot 2; soil 16,
pot 3 ; soil 19, pot 3 ; soil 20, pot 2 ; soil 22, pot 2 ; soil 23, pot 1 ; soil 21, pot 2 ;
soil 2.1, pot 1.
Hanford Fine Sandy Loam — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Dwarf milo A. Left to right— Soil 15, pot 1; soil 15, pot 2; soil 15,
pot 3; soil 20, pot 1; soil 20, pot 2; soil 20, pot 3; soil 23, pot 1; soil 23, pot 2;
soil 23, pot 3.
1
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON ] PLATE 54
I
Haxford Fixe Sandy Loam — First Crop
Pota of same and different representatives of a given soil type compared.
Fig. 1. Dwarf milo B. Left to right — Soil 14, pot 3; soil 15, pot 2; soil lb',
pot 1 : soil H», pot 3; soil 20, pot 2; soil 22, pot 3; soil 23, pot 3; soil 24, pot 2;
soil 25, pot •">.
:i
Haxford Fine Sandy Loam — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Dwarf milo B. Left to right— Soil 14, pot 1; soil 14, pot 2; soil 14,
pot 3; soil 22, pot 1; soil 22, pot 2; soil 22, pot 3; soil 23, pot 1; soil 23, pot 2;
soil 23, pot 3.
i
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 55
Haxford Fixe Sandy Loam — First (jrop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Soy beans. Left to right — Soil 14, pot 1; soil 15, pot 1; soil 16,
pot 2; soil L9, pot 2; soil 20, pot 3: soil 22, pot 1; soil 23, pot 3; soil 24, pot 1;
soil 2.", pot 3.
Haxford Fine Sandy. Loam — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Soy beans. Left to right— Soil 14, pot 1; soil 14, pot 2; soil 14,
pot 3; soil 16, pot 1; soil 16, pot 2; soil 16, pot 3; soil 23, pot 1; soil 23, pot 2;
soil 23, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON ] PLATE 56
Haxford Fine Sandy Loam — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Cowpeas B. Left to right— Soil 14, pot 1; soil 14, pot 2; soil 14,
pot 3; soil 22, pot 1 ; soil 22, pot 2; soil 22, pot 3; soil 23, pot 1; soil 23, pot 2;
soil 2:;, pot :;.
*;
Mi ' ££&
A I A ii^A A A* A
Hanford Fine Sandy Loam — First Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Cowpeas B. Left to right — Soil 14, pot 3; soil 15, pot 2; soil 16,
pot 2; soil 19, pot 2; soil 20, pot 2; soil 22, pot 2; soil 23, pot 2; soil 24, pot 1;
soil 25, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON ] PLATE 57
1
i
/
'J^
tf ?*iLBgMi
g^agfe
i
£gi
^ "f
£**
*
gMflpfc
&t$m
\
Hanford Fixe Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Barley, following soy beans. Left to right — Soil 14, pot 2; soil 15,
pot I ; soil 16, pot 3; soil 19, pot 3; soil 20, pot 1; soil 22, pot 2; soil 23, pot 3;
soil 24, pot •"> : soil 2-"), pot 1.
Hanford Fine Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Barley, following soy beans. Left to right — Soil 14, pot 1; soil 14,
pot 2; soil 14, pot 3; soil 19, pot 1; soil 19, pot 2; soil 19, pot 2; soil 19, pot 3;
soil 23, pot 1; soil 23, pot 2; soil 23, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 58
|M | t J
]
If I
V:'
;«l» v !ii Es&sJLJL'U
MM
?-<*izm?
i**&m&>m«T^a& ! '* v&n "•itfafiK^vss.
IIaxford Fine Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Wheat, following millet. Left to right — Soil 14, pot 1; soil 15, pot 1; soil 16,
pot 1; soil 19, pot 3; soil 20, pot 1; soil 22, pot 1; soil 23, pot 1; soil 24, pot 1;
soil 25, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 59
.
Hanford Fine Sandy Loam — Second Crop
Pots of same ami different representatives of a given soil type compared.
Wheat, folio-wing millet. Left to right — Soil 16, pot 1 ; soil 16, pot 2 ; soil 16,
pot 3; soil 22, pot 1 ; soil 22, pot 2; soil 22, pot 3; soil 24, pot 1; soil 24, pot 2;
soil 24, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 60
Hanford Fixe Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Barley, following cowpeas. Left to right — Soil 14, pot 2; soil 15,
pot ::; soil 16, pot 2; soil ]9, pot 2; soil 20, pot 1; soil 22, pot 3; soil 23, pot 3;
soil 24, pot :'» ; soil 2.1, pot 1.
'.
Haxford Fine Sandy Loam — Second Chop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Barley, following cowpeas. Left to right — Soil 19, pot 1; soil ]9,
pot 2; soil j 9, pot 3; soil 20, pot 1; soil 20, pot 2; soil 20, pot 3; soil 23, pot 1;
soil 23, pot 2 ; soil 23, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 61
Hanford Fine Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 1. Oats, following milo. Left to right — Soil 14, pot 3; soil 15, pot 2;
soil 16, pot 2; soil 19, pot 1; soil 20, pot 2; soil 22, pot 1; soil 23, pot 3; soil 24,
pot 1 ; soil 25, pot 1.
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Hanford Fine Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Fig. 2. Oats, following milo. Left to right — Soil 14, pot 1 ; soil 14, pot 2 ;
soil 14, pot 3; soil 15, pot 1; soil 15, pot 2; soil 15, pot 3; soil 24, pot 1; soil 24,
pot 2; soil 24, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON ] PLATE 62
Hanford Fine Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Melilotus indica, following eowpeas. Left to right — Soil 14, Pot 1; Soil 15,
Pot 3; Soil 16, Pot 2; Soil 19, Pot 2; Soil 20, Pot 1.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 63
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Hanford Fine Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Melilotus indica, following eowpeas. Left to right — Soil 22, Pot 2; Soil 23,
Pot ] ; Soil 24, Pot 1; Soil 25, Pot 1.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON ] PLATE 64
Hanford Fine Sandy Loam — Second Chop
Pots of same and different representatives of a given soil type compared.
Melilotus indica, following cowpeas. Left to right — Soil 15, Pot 1; Soil 15,
Pot 2; Soil 15, Pot 3; Soil 23, Pot 1.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON ] PLATE 65
IIanf-ord Fine Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Melilotus indica, following cowpeas. Left to right— Soil 23, Pot 2; Soil 23,
Pot 3; Soil 25, Pot 1 ; Soil 25, Pot 2; Soil 25, Pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON ] PLATE 66
•
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-^■P\. —
--
Haxford Fixe Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Bur clover, following milo. Left to right — Boil 14, Pot 1 ; Soil 15, Pot 1;
Soil 16, Pot 2; Soil 19, Pot 1: Soil 20, Pot 1.
Haxford Fixe Saxdy Loam — Secoxd Crop
Pots of same and different representatives of a given soil type compared.
Bur clover following milo. Left to right— Soil 22, Pot 1 ; Soil 23, Pot 1
Soil 24, Pot 1; Soil 2o, Pot 1.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON ] PLATE 67
Haxford Fine Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Bur clover, following milo. Left to right— Soil 19, Pot 1; Soil 19, Pot 2;
Soil 19, Pot 3; Soil 23, Pot 1; Soil 23, Pot 2.
*5k t^tit
Hanford Fine Sandy Loam — Second Crop
Pots of same and different representatives of a given soil type compared.
Bur clover, following milo. Left to right— Soil 23, Pot 3; Soil 25, Pot 1
Soil 23, Pot 2: Soil 23, Pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 68
San Joaquin Sandy Loam
Pots of same and different representatives of a given soil type compared.
Eye. Left to right— Soil 10, pot 2; soil 11, pot 1; soil 12, pot 2; soil 13,
pot 3; soil 17, pot 3; soil 18, pot 1; soil 21, pot 1; soil 26, pot 1.
UNIV. CALIF. FUBL. AGR. SCI. VOL.
r PENDLETON ] PLATE 69
San Joaquin Sandy Loam
Pots of same and different representatives of a given soil type compared.
Fig. 1. Melilotus indica. Left to right— Soil 10, pot 1; soil 11, pot 3; soil 12,
pot 2; soil 13, pot 1; soil 17, pot 3; soil 18, pot 3; soil 21, pot 2; soil 28, pot 1.
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San Joaquin Sandy Loam
Pots of same and different representatives of a given soil type compared.
Fig. 2. Melilotus indica. Left to right — Soil 13, pot 1; soil 13, pot 2; soil 13,
pot 3; soil 17, pot 1; soil 17, pot 2; soil 17, pot 3; soil 26, pot 1; soil 28, pot 2;
soil 26, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 70
San Joaquin - Sandy Loam
Pots of same and different representatives of a given soil type compared.
Eye. Left to right — Soil 10, pot 1; soil 10, pot 2; soil 10, pot 3; soil 18,
pot 1; soil 18, pot 2; soil 18, pot 3; soil 26, pot 1; soil 26, pot 2; soil 26, pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL, 3
[PENDLETON] PLATE 71
San Joaquin Sandy Loam
Pots of same and different representatives of a given soil type compared.
Fig. 1. Barley. Left to right— Soil 10, pot 3; soil 11, pot 2; soil 12, pot 3;
soil 13, pot 1; soil 17, pot 3; soil 18, pot 2; soil 21, pot 3; soil 26, pot 1.
San Joaquin Sandy Loam
Pots of same and different representatives of a given soil type compared.
Fig. 2. Barley. Left to right— Soil 10, pot 1 ; soil 10, pot 2 ; soil 10, pot 3 ;
soil 18, pot 1; soil 18, pot 2; soil 18, pot 3; soil 26, pot 1; soil 26, pot 2; soil 23,
pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 72
Jf^fe^WjES!
San Joaquin Sandy Loam
Pots of same and different representatives of a given soil type compared.
Fig. 1. Oats. Left to right — Soil 10, pot 1; soil 11, pot 1; soil 12, pot 2;
soil 13, pot 1; soil 17, pot 2; soil 18, pot 3; soil 21, pot 1; soil 28, pot 3.
San Joaquin Sandy Loam
Pots of same and different representatives of a given soil type compared.
Fig. 2. Oats. Left to right— Soil 11, pot 1; soil 11, pot 2; soil 11, pot 3;
soil 17, pot 1; soil 17, pot 2; soil 17, pot 3; soil 21, pot 1; soil 21, pot 2; soil 21.
pot 3.
UNIV. CALIF, PUBL. AGR. SCI. VOL. 3
[PENDLETON] PLATE 73
i >
San Joaquin Sandy Loam
Pots of same and different representatives of a given soil type compared.
Fig. 1. Wheat. Left to right— Soil 10, pot 1. ; soil 11, pot 3; soil 12, pot 1;
soil 13, pot ] ; soil 17, pot 1; soil 18, pot 2; soil 21, pot 1; soil 26, pot 3.
San Joaquin Sandy Loam
Pots of same and different representatives of a given soil type compared.
Fig. 2. Wheat. Left to right— Soil 10, pot 1; soil 10, pot 2; soil 10, pot 3;
soil 13, pot 1; soil 13, pot 2; soil 13, pot 3; soil 17, pot 1; soil 17, pot 2; soil 17,
pot 3.
UNIV. CALIF. PUBL. AGR. SCI. VOL. 3
[ PENDLETON ] PLATE 74
fc'-
IV.vi
i
San Joaquin Sandy Loam
Pots of same and different representatives of a given soil type compared.
Fig. 1. Bur clover. Left to right— Soil 10, pot 2; soil 11, pot 2; soil 12,
pot 3; soil 13, pot 1; soil 17, pot 3; soil 18, pot 2; soil 21, pot 1; soil 26, pot 3.
San Joaquin Sandy Loam
Pots of same and different representatives of a given soil type compared.
Fig. 2. Bur clover. Left to right— Soil 10, pot 1; soil 10, pot 2; soil 10,
pot 3; soil 18, pot 1; soil 18, pot 2; soil 18, pot 3; soil 26, pot 1; soil 26, pot 2;
soil 26, pot 3.