University of California— College of Agriculture, 
 
 AGRICULTURAL EXPERIMENT STATION, 
 
 E. W. HILGARD, Director. 
 
 NATURE, VALUE, AND UTILIZATION 
 OF ALKALI LANDS. 
 
 
 Alkali Spots Before Reclamation. Tulare Experiment Substation. 
 
 BY 
 
 E. W. HILGARD. 
 
 BULLETIN No. 128. 
 
 (March, 1900.) 
 
 SACRAMENTO: 
 a. j. johnston, : : : : : superintendent state printing. 
 
 1900. 
 
TABLE OF CONTENTS. 
 
 Page. 
 
 Occurrence and Characteristics of Alkali Soils 3 
 
 How Plants are Injured by Alkali 5 
 
 Effects of Irrigation __ 5 
 
 Determination of the Distribution of the Alkali Salts _ 6 
 
 Composition of Alkali Salts; summary of conclusions 13 
 
 Utilization and Reclamation of Alkali Lands . 14 
 
 Counteracting Evaporation; Diluting the Alkali Salts ; Chemical Remedies; 
 
 Stable Manure and Other Fertilizers _. 14-18 
 
 Removing the Salts from the Soil 19 
 
 Will it Pay to Reclaim Alkali Lands 20 
 
 Crops Suitable for Alkali Lands _ 22 
 
 Amount of Salts Compatible with Ordinary Crops. 24 
 
 Grasses ; Legumes ; Weeds ; Root Crops ; Textile Plants ; Grapevines ; Citrus 
 
 Trees; Deciduous Orchard Trees ; Timber and Shade Trees 24-29 
 
 Irrigation with Saline Waters 30 
 
 Limits of Saline Contents _ -...._ . 31 
 
 Reclaimable and Irreclaimable Alkali Lands as distinguished by their Natural 
 
 Vegetation ._ 35 
 
 Tussock Grass ; Greasewood ; Dwarf Samphire ; Bushy Samphire ; Saltwort ; 
 
 Alkali-Heath; Cressa _ 37-44 
 
 Relative Tolerance of the Different Species 44 
 
 Total Salt Indicators; Salsoda Indicators; Neutral Salt Indicators 46 
 
 ILLUSTRATIONS. 
 
 Alkali Spots before Reclamation... Title-page. 
 
 Diagrams showing Distribution of Alkali Salts ..7, 8, 10, 11 
 
 Wheat on Soil crusted with White Alkali... ._ 17 
 
 Alkali Lands in San Joaquin Valley 21 
 
 Orange Trees irrigated with Artesian Water 32 
 
 Orange Trees irrigated with Alkali Water of Elsinore Lake 33 
 
 Alkali Grasses: Tussock Grass; Greasewood; Dwarf Samphire; Bushy Samphire; 
 
 Saltwort; Alkali-Heath; Cressa 37-44 
 
THE NATURE, VALUE, AND UTILIZATION OF 
 ALKALI LANDS.* 
 
 By E. W. Hilgaed. 
 
 [The continuous and pressing demand for information on alkali lands and their 
 utilization having exhausted the printed matter heretofore published by this Station 
 on the subject, it seems best to publish a brief general summary of the results of our 
 investigations, made during the past twenty years, for the use of farmers and land 
 owners and the general public. Those desiring more detailed information will find the 
 record, so far as printed, in the reports of the Station from 1879 to 1898.] 
 
 Occurrence and Characteristics of Alkali Soils. 
 
 Alkali lands must be pointedly distinguished from the salty lands of 
 sea margins or marshes, from which they differ in both their origin and 
 essential nature. Marsh lands derive their salts from sea water that 
 occasionally overflows them, and the salts which impregnate them are 
 essentially "sea salts"; that is, common salt, together with bittern, 
 epsom salt, etc. Very little of what would be useful to vegetation or 
 desirable as a fertilizer is contained in the salts impregnating such 
 soils; and they are by no means always intrinsically rich in plant 
 food, but vary greatly in this respect. 
 
 Alkali lands bear no definite relation to the sea; they are mostly 
 remote from it or from any former sea bed, so that they have sometimes 
 been designated as "terrestrial salt lands." Their existence is usually 
 definitely traceable to climatic conditions alone. They are the natural 
 result of a light rainfall, insufficient to leach out of the land the salts 
 that always form in it by the progressive weathering of the rock 
 powder of which all soils largely consist. Where the rainfall is 
 abundant, that portion of the salts corresponding to "sea salts" is 
 leached out into the bottom water, and with this passes through 
 springs and rivulets into the country drainage, to be finally carried to 
 the ocean. Another portion of the salts formed by weathering, however, 
 is partially or wholly retained by the soil; it is that portion chiefly 
 useful as plant-food. 
 
 It follows that when, in consequence of insufficient rainfall, all or 
 most of the salts are retained in the soil, they will contain not only 
 
 * Revision of a paper published in the Yearbook of the U. S. Department of Agricul- 
 ture for 1895, with abstracts from reports and records of the California Experiment 
 Station. 
 
— 4 — 
 
 the ingredients of sea water, but also those useful to plants. In rainy 
 climates a large portion even of the latter is leached out and carried 
 away. In extremely arid climates their entire mass remains in the 
 soils; and, being largely soluble in water, evaporation during the dry 
 season brings them to the surface, where they may accumulate to such 
 an extent as to render the growth of ordinary useful vegetation impos- 
 sible; as is seen in "alkali spots," and sometimes in extensive tracts of 
 "alkali desert." 
 
 In looking over a rainfall map of the globe we see that a very consider- 
 able portion of the earth's surface has deficient rainfall, the latter term 
 being commonly meant to imply any annual average less than 20 
 inches (500 millimeters). The arid region thus defined includes, in 
 North America, most of the country lying west of the one hundredth 
 meridian up to the Cascade Mountains, and northward beyond the 
 line of the United States; southward, it reaches far into Mexico, includ- 
 ing especially the Mexican plateau. In South America it includes 
 nearly all the Pacific Slope (Peru and Chile) south to Araucania; and 
 eastward of the Andes, the greater portion of the plains of western 
 Brazil and Argentina. In Europe only a small portion of the Mediter- 
 ranean border is included; but the entire African coast belt opposite, 
 with the Saharan and Libyan deserts, Egypt, and Arabia are included 
 therein, as well as a considerable portion of South Africa. In Asia, 
 Asia Minor, Syria (with Palestine), Mesopotamia, Persia, and north- 
 western India up to the Ganges, and northward, the great plains or 
 steppes of central Asia eastward to Mongolia and western China, fall 
 into the same category; as does also a large portion of the Australian 
 continent. 
 
 Over these vast areas alkali lands occur to a greater or less extent, 
 the exceptions being the mountain regions and adjacent lands on the 
 side Exposed to prevailing oceanic winds. It will therefore be seen that 
 the problem of the utilization of alkali lands for agriculture is not of 
 local interest only, but is of world-wide importance. It will also be 
 noted that many of the countries referred to are those in which the 
 most ancient civilizations have existed in the past, but which at 
 present, with few exceptions, are occupied by semicivilized people 
 only. It is doubtless from this cause that the nature of alkali lands 
 has until now been so little understood that even their essential dis- 
 tinctness from the sea-border lands has been but lately recognized in 
 full. Moreover, the great intrinsic fertility of these lands has been 
 very little appreciated, their repellent aspect causing them to be gen- 
 erally considered as waste lands. 
 
 This aspect is essentially due to their natural vegetation being in 
 most cases confined to plants useless to man, commonly designated 
 as " saline vegetation," of which but little is usually relished by 
 
— 5 — 
 
 cattle. Notable exceptions to this rule occur in Australia and Africa, 
 where the " saltbushes " of the former and the " karroo " vegetation of 
 the latter form valuable pasture grounds. Apart from these, however, 
 the efforts to find for these lands while in their natural condition, cul- 
 ture plants generally acceptable, or at least profitable, outside of forage 
 crops, have not been very successful. 
 
 How Plants Are Injured by Alkali. 
 
 When we examine plants that have been injured by alkali, we will 
 usually find that the damage has been done near the base of the trunk, 
 or root crown; rarely at any considerable depth in the soil itself. In the 
 case of green herbaceous stems, the bark is found to have turned to a 
 brownish tinge for half an inch or more, so as to be soft and easily 
 peeled off. In the case of trees, the rough bark is found to be of a dark, 
 almost black, tint, and the green layer underneath has, as in the case 
 of an herbaceous stem, been turned brown to a greater or less extent. 
 In either case the plant has been practically "girdled," the effect being 
 aggravated by the diseased sap poisoning, more or less, the whole stem 
 and roots. The plant may not die, but it will be quite certain to become 
 unprofitable to the grower. 
 
 It is mainly in the case of land very heavily charged with common 
 salt, as in the marshes bordering the sea or salt lakes, that injury arises 
 from the direct effects of the salty soil-water upon the feeding roots 
 themselves. In a few cases the gradual rise of salt water from below, 
 in consequence of defective drainage, has seriously injured, and even 
 destroyed, old orange orchards. 
 
 The fact that in cultivated land the injury is usually found to occur 
 near the surface of the soil, concurrently with the well-known fact that 
 the maximum accumulation of salts at the surface is always found near 
 the end of the dry season, indicates clearly that this accumulation is 
 due to evaporation at the surface. The latter is often found covered 
 with a crust consisting of earth cemented by the crystallized salts, and 
 later in the season with a layer of whitish dust resulting from the 
 drying-out of the crust first formed. It is this dust w r hich becomes so 
 annoying to the inhabitants and travelers in alkali regions, when high 
 winds prevail, irritating the eyes and nostrils and parching the lips. 
 
 Effects of Irrigation. 
 
 One of the most annoying and discouraging features of the cultiva- 
 tion of lands in alkali regions is that, although in their natural 
 condition they may show but little alkali on their surface, and that 
 mostly in limited spots, usually somewhat depressed below the general 
 surface, these spots are found to enlarge rapidly as irrigation is prac- 
 ticed; and since alkali salts are the symptoms and result of insufficient 
 
— 6 — 
 
 rainfall, irrigation is a necessary condition of agriculture wherever 
 they prevail. Under irrigation, neighboring spots will oftentimes 
 merge together into one large one, and at times the entire area, once 
 highly productive and perhaps covered with valuable plantations of 
 trees or vines, will become incapable of supporting useful growth. 
 This annoying phenomenon is popularly known as " the rise of the 
 alkali " in the western United States, but is equally well known in 
 India and other irrigation regions. 
 
 The process by which the salts rise to the surface is the same as that 
 by which oil rises in a wick. The soil being impregnated with a solution 
 of the alkali salts, and acting like the wick, the salts naturally remain 
 behind on the surface as the water evaporates, the process only stopping 
 when the moisture in the soil is exhausted. We thus not infrequently 
 find that after an unusually heavy rainfall there follows a heavier accu- 
 mulation of alkali salts at the surface, while a light shower produces no 
 perceptible permanent effect. We are thus taught that, within certain 
 limits, the more water evaporates during the season the heavier will be 
 the rise of the alkali; provided that the water is not so abundant as to 
 leach the salts through the soil and subsoil into the subdrainage. 
 
 Worst of all, however, is the effect of irrigation ditches laid in sandy 
 lands (such as are naturally predominant in arid regions), without proper 
 provision against seepage. The ditch water then gradually fills up the 
 entire substrata so far as they are permeable, and the water-table rises 
 from below until it reaches nearly to the ditch level; shallowing the 
 subsoil, drowning out the deep roots of all vegetation, and bringing close 
 to the surface the entire mass of alkali salts previously diffused through 
 many feet of substrata. If this condition is allowed to continue for 
 some time, alkali salts originally "white" will by a chemical change 
 become "black" by the formation of carbonate of soda from the glauber 
 salt; greatly aggravating the injury to vegetation. More than this, if 
 such swamping is allowed to continue for a number of years, the land 
 may be permanently injured; so that even after the alkali is removed, 
 the soil remains inert and unthrifty for years. 
 
 Determination of the Distribution of the Alkali Salts. 
 
 In order to gain a basis for the possible means of reclaiming alkali 
 lands, it is evidently necessary to determine by direct observation the 
 manner in which the salts are distributed in the soils under different 
 conditions. This can be done by sampling the soil at short intervals of 
 depth, and leaching out and analyzing each sample separately. While 
 this involves a great deal of work, it is manifestly the only conclusive 
 method. 
 
 A series of such investigations has been first carried out by the Cali- 
 fornia Experiment Station during the years 1894 and 1895, with samples 
 
— 7 — 
 
 taken in or near the substations 
 near Tulare and Chino, Cal., 
 with the results as given below. 
 It should be understood that 
 the alkali in the Tulare region 
 is mostly of the "black" kind, 
 that is, consisting largely of car- 
 bonate of soda, which dissolves 
 the humus of the soil and thus 
 gives rise to dark-colored spots 
 and water-puddles. The soil is 
 a rather sandy, gray loam (see 
 Report California Experiment 
 Station, 1889). On the Chino 
 tract, on the contrary, the soil 
 is a close-grained, rather heavy 
 loam, naturally subirrigated; 
 the salts are likewise mostly 
 " black," the sodium carbonate 
 being about one third of the 
 whole. 
 
 Fig. 1 represents the condition 
 of the salts in an "alkali spot" 
 as found at the end of the dry 
 season at the Tulare substa- 
 tion. The soil was sampled to 
 the depth of 2 feet, at intervals 
 of 3 inches each. The depths 
 are entered in the vertical line 
 to the left; the percentages of 
 the total salts and of each of the 
 principal ingredients are entered 
 in decimal fractions of 1 per 
 cent on horizontal lines running 
 to the right, as indicated on the 
 top line of the plate. Broken 
 lines connecting the data in each 
 case facilitate the understanding 
 of the results. It is thus easy 
 to see that at this time almost 
 the entire mass of the salts was 
 accumulated within the first six 
 inches from the surface, while 
 lower down the soil contained 
 so little that few culture plants 
 
 ^ 
 & ' 
 
 1 
 
 <o 
 
 ' $ 
 
 
 
 L 
 
 
 * 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 1) 
 
 
 ^ 
 
 
 
 
 
 
 1 
 1 i 
 
 
 
 
 
 
 
 
 \ 
 
 * 
 
 
 
 
 
 
 3T 
 
 \ 
 
 
 
 
 
 
 
 
 \ 
 
 * 
 
 
 
 
 
 
 
 \ 
 
 
 
 
 
 
 
 i_ 
 
 \ 
 
 J) 
 
 
 
 
 
 
 jr 
 
 \ 
 
 
 
 
 
 
 
 _r 
 
 \ 
 
 ^4 
 
 
 
 
 
 
 _r 
 
 
 \ 
 
 
 
 
 
 
 T 
 
 
 '* 
 
 
 
 
 
 
 T 
 
 
 \^ 
 
 
 
 
 
 
 J[ 
 
 
 ^ 
 
 
 
 
 
 
 ~t 
 
 ,3 
 
 I* 
 
 1 
 
 
 
 
 
 
 j. 
 
 a .i 
 
 ft 
 
 
 
 
 
 
 \ 
 
 
 < 
 
 
 
 
 
 
 + 
 
 4 
 
 i 
 
 & 
 
 
 V 
 4. 
 
 
 
 
 
 >4 
 
 
 ^; 
 
 \ 
 
 
 
 
 
 
 1 ^ 
 
 
 
 
 
 
 
 '4 
 
 \ 
 
 
 
 
 
 
 
 < + 
 
 \ 
 
 
 
 
 
 
 
 
 \ 
 
 \ 
 
 
 
 
 
 
 ^1 
 
 ■s' 
 
 4 isA 
 
 \ 
 
 
 
 
 
 
 
 
 y 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 B^Jou 
 
 ??ux 
 
 '£% 
 
 *+ + ■ 
 
 >-M 
 
 v<+. 
 
 
 
 
 
 
 **} <0 ^ <\i 
 
 =5 5 ^ J6 , 
 
 j 1 
 
 s < 
 
 would be hurt by them. 
 
J* 
 
 
 
 **> 
 
 k 
 t 
 
 Si 
 |« 
 
 *s 
 
 e 
 
 |% 
 
 Si 
 
 3 
 
 
 
 
 
 
 
 
 % 
 
 
 
 y\ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 A 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 \ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 [ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ! 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 /» 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 f 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 i 
 
 l 
 
 
 1 
 
 \ 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 l 
 i 
 
 t 
 
 i 
 
 \ 
 \ 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 -1 
 
 1 
 
 l 
 
 i 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 3 
 
 
 <? 
 
 \ 
 \ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 T 
 
 'i 
 
 1 
 
 \ 
 \ 
 
 r 
 
 
 
 
 
 
 
 
 
 
 
 
 SI 
 
 l<S 
 
 
 \ 
 \ 
 
 r 
 
 
 
 
 
 
 
 
 
 
 
 
 1 i 
 
 
 
 
 ii 
 
 
 
 
 
 
 
 
 
 
 
 
 J h 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 / ' 
 Ii 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 •ft 
 
 ' / 
 
 / 
 
 
 
 
 \\ 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 / 
 / 
 
 
 
 
 \\ 
 \\ 
 
 
 
 
 
 
 
 
 
 
 K 
 
 / 
 
 f 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 An 
 
 v; 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ft 
 
 / 
 
 / 
 
 
 
 
 
 ^ 
 
 V 
 
 
 
 
 
 
 
 
 *7 
 
 / 
 
 V 
 
 
 
 
 
 
 K 
 
 
 
 
 
 
 
 
 // 
 // 
 // 
 
 
 
 
 
 1) 
 
 
 
 v 
 
 \ 
 
 
 
 
 
 
 
 // 
 
 7 
 
 
 
 
 * * 
 
 1 ■ 
 
 vA 
 
 
 
 \ 
 
 V 
 
 
 
 
 
 .. // 
 
 
 
 ^ 
 
 s 
 
 ' 1 
 
 % 
 
 % 
 
 \ 
 
 
 
 \ 
 
 v^ 
 
 
 
 
 Si 
 i 
 
 .-& 
 
 c 
 
 
 
 V 
 
 % 
 
 
 K. 
 
 
 
 \ 
 
 E>~r^ 
 
 +■+ $ *> — 
 
 *^*A 
 
 
 
 
 
 **♦♦ 
 
 * 
 
 
 
 
 
 
 
 N 
 
 . <n <a o> 54 
 
 5 .. i. 
 
 !Q 5. Sfc fc 
 
 
 > > 
 
— 9 — 
 
 Fig. 2 represents similarly the state of things in a natural soil along- 
 side of the alkali spot, but in which the native vegetation of brilliant 
 flowers develops annually without any hindrance from alkali. Samples 
 were taken from this spot in March, near the end of the wet, and in 
 September, near the end of the dry, season, and each series fully 
 analyzed. There was scarcely a noticeable difference in the results 
 obtained. It is seen in the figure that down to the depth of 15 inches 
 there was practically no alkali found (0.035%), and it was within these 15 
 inches of soil that the native plants mostly had their roots and developed 
 their annual growth. But from that level downward the alkali rapidly 
 increased, and reached a maximum (0.529%) at about 33 inches, decreas- 
 ing rapidly thence until, at the end of the fourth foot in depth, there was 
 no more alkali than within the first foot from the surface. In other 
 words, the bulk of the salts had accumulated at the greatest depth to 
 which the annual rainfall (7 inches) ever reaches, forming there a sheet 
 of tough, intractable clay hardpan. The shallow-rooted native plants 
 germinated their seeds freely on the alkali-free surface, their roots kept 
 above the strongly charged subsoil, and through them and the stems 
 and foliage all the soil moisture was evaporated by the time the plants 
 died. Thus no alkali was brought up from below by evaporation. The 
 seeds shed would remain uninjured, and would again germinate the 
 coming season. 
 
 It is thus that the luxuriant vegetation of the San Joaquin plains, 
 dotted with occasional alkali spots, is maintained, the spots them- 
 selves being almost always depressions in which the rain water may 
 gather, and where, in consequence of the increased evaporation, the 
 noxious salts have risen to the surface and render impossible all but 
 the most resistant saline growth; particularly when, in consequence of 
 maceration and fermentation in the soil, the formation of carbonate of 
 soda (black alkali) has caused the surface to sink and become almost 
 water-tight. 
 
 After several years' cultivation with irrigation on the same land as 
 in the last figure, a crop of barley 4 feet high was grown on the land. 
 Investigation proved that here the condition of the soil was intermediate 
 between the two preceding figures. The irrigation water had dissolved 
 the alkali of the subsoil, and the abundant evaporation had brought it 
 nearer the surface; but the shading by the barley crop and the evapo- 
 ration of the moisture through its roots and leaves had prevented the 
 salts from reaching the surface in such amounts as to injure the crop, 
 although the tendency to rise was clearly shown. 
 
 Ten feet from this spot was bare alkali ground on which barley had 
 refused to grow. Its examination proved it to contain a somewhat 
 larger proportion (one-fifth more) of alkali salts, and in these a larger 
 relative proportion of carbonate of soda (salsoda). Thus the seed was 
 mostly destroyed before germination, and of the few seedlings none 
 
— 10 
 
 lived beyond the fourth leaf. On the ground represented by Fig. 1, 
 previous treatment with gypsum had so far diminished the salsoda 
 that the grain germinated freely, and a very good crop of barley was 
 harvested there without irrigation. The same season, grain crops were 
 almost a failure on alkali-free land in the same region. 
 
 In connection with this result it should be noted as a general fact 
 
 Amounts of Ingredients in 100 of Soil. 
 O . 02 Q« OS Off SO /2 '¥ /6 /# .20 .22 
 
 Fig. 3. Distribution of alkali salts in sandy land. 
 
 that alkali lands always retain a certain amount of moisture perceptible 
 to the hand during the dry season, and that this moisture can be 
 utilized by crops; so that at times when crops fail on nonalkaline land, 
 good ones are obtained where a slight taint of alkali exists in the soil. 
 Striking examples of this fact occur in the Spokane country within the 
 great bend of the Columbia River, in the State of Washington; and the 
 
— 11 
 
 same is illustrated by the luxuriant growth of weeds on the margin of 
 alkali spots, just beyond the limit of corrosive injury. Actual deter- 
 mination showed that while a sample of alkali soil containing .54 per 
 cent of salts absorbed 12.3 per cent of moisture from moist air, the same 
 soil when leached absorbed only 2.5 per cent — a figure corresponding to 
 that of sandy upland loams. Investigation at the Tulare substation 
 during the dry season of 1898 also showed the presence of 15 and 16 per 
 cent of water, respectively, in strong u white" and " black" alkali soils, 
 while in adjoining light alkali soils there was but 10 per cent. 
 
 In very sandy lands, and particularly when the alkali is "white" 
 only, the tendency to accumulation near the surface is much less, even 
 
 under irrigation. 
 
 In the natural condition the salts are in such cases 
 
 Amounts of Alkali Salts in 100 or Soil. 
 
 
 
 J>X. .OU Xt. .1 
 
 •>* 
 
 'ill" 
 
 'U 
 
 
 
 
 
 
 
 /¥" 
 
 
 + i ( 
 
 f (1 
 
 /$ 
 fc 
 
 
 
 ■ ■+*<■■ 
 
 
 
 
 
 r ** 
 
 1 /£ 
 
 
 
 
 w 
 
 in 
 
 oh 6 
 
 
 
 4 
 
 ,1 
 
 1 
 
 
 
 
 
 o .oi. .on .ot. .or ./ 
 
 ./ 
 
 x. ./* 
 
 (. / 
 
 f ,JtO ,Z3. .3.* 2-I- 2? 3C 
 
 
 - ■ : 
 
 \\ 
 
 *\ 
 
 
 
 
 
 
 
 
 A 
 
 
 
 
 /_ 
 
 \ 
 
 id 
 
 
 \ j 
 
 
 
 
 
 
 
 7 
 
 
 
 
 / 
 
 
 *il 
 
 
 & 
 
 
 
 
 
 
 &»# 
 
 
 
 
 
 
 
 
 
 y 
 
 */\ 
 
 # 
 
 s0 
 
 ^ 
 
 rp 
 
 \<^, 
 
 
 
 
 
 
 
 
 
 5 J?b 
 
 i / 
 
 1 
 
 
 £r 
 
 
 
 1 
 
 t H 
 
 // 
 
 
 
 
 PLo/- <? 
 
 < 
 
 i\*A 
 
 // 
 
 
 
 
 
 Fig. 4. Distribution of alkali salts in close-texiured soil of the ten-acre tract, near Chino, Cal. 
 
 often found quite evenly distributed through soil columns of four feet, 
 and even more. This is an additional cause of the lesser injuriousness 
 of "white alkali." 
 
 Fig. 3 shows the distribution of the salts as found in a very sandy 
 area on the Tulare substation grounds. It should be noted that here, 
 while the general figure representing the distribution is very similar to 
 that showing the same in a close soil (see Fig. 4) the salts reach down 
 to over 6 feet, and are at their maximum 18 inches from, instead of at 
 the surface. 
 
 The mode of distribution of alkali salts in the heavier, close-grained 
 soil of the Chino tract is illustrated in Fig. 4. As has been mentioned, 
 this land is permanently moist, from a water-table ranging from 5 to 7 
 
— 12 — 
 
 feet below the surface in ordinary years. There is therefore no oppor- 
 tunity for the formation of "alkali hardpan" as in the case of the 
 Tulare soil; the salts always remain rather near the surface, viz, within 
 12 to 18 inches. But being in much smaller average amounts than at 
 Tulare (an average of about 5,300 pounds per acre), quite a copious 
 natural vegetation of grasses, sunflowers, anc£" verba mansa" covered 
 the whole surface, save in a few low spots. 
 
 A similar mode of distribution of the salts is found in the more clayey 
 "black adobe" lands of the Great Valley of California. The scanty 
 rains cannot penetrate these soils to any great depth, so that evapora- 
 tion will soon bring the salts carried by them back to within a short 
 distance of the surface. Their accumulation there is frequently indi- 
 cated by the entire absence of any but the most resistant alkali weeds, 
 even though the total of salts in the land may not be very great. 
 
 While the phenomena of alkali lands as outlined above undoubtedly 
 represent the vastly predominant conditions on extensive level lands, 
 yet there are exceptions due to surface conformation, and to the local 
 existence of sources of alkali salts outside of the soil itself. Such is the 
 case where salts ooze out of strata cropping out on hillsides, as is the 
 case at some points in the San Joaquin Valley in California, and in 
 parts of Colorado, Wyoming, and Montana. In such cases the alkali 
 salts may be most apparent near the foot of the hills, and in light, 
 well-drained valley lands may disappear altogether before reaching the 
 valley-trough. 
 
 On the other hand, it not infrequently happens that in sloping val- 
 leys or basins, where the central (lowest) portion receives the salts 
 leached out of the adjacent hills and valley slopes in consequence 
 of slow subdrainage, we find belts of greater or less width in which the 
 alkali impregnation may reach to the depth of 10 or 12 feet, usually 
 within more or less definite layers of calcareous hardpan, likewise the 
 outcome of the leaching of the valley slopes. Such areas, however, are 
 usually quite limited, and are, of course, scarcely reclaimable without 
 excessive expenditure, the more as they are often underlaid by saline 
 bottom water. In these cases the predominant saline ingredient is 
 usually common salt, as might be expected, and as is exemplified on a 
 large scale in the Great Salt Lake of Utah, and in the ocean itself. 
 
 In many cases, in California and elsewhere, the over-irrigation of 
 bench or slope lands has caused, first the lower slopes, and then the 
 bottom lands of streams and rivers, to be overrun with alkali salts, 
 although before irrigation was practiced these lands were exempt from 
 them. In some portions of the San Joaquin Valley this trouble has 
 become most serious, fertile lands long under successful cultivation 
 being rendered useless by thousands of acres, unless an expensive 
 system of underdrainage were resorted to. Even this remedy is largely 
 
— 13 — 
 
 inapplicable in the absence of legislation providing for right-of-way for 
 drainage as well as for irrigation; but any such legislation should, at 
 the same time, provide a remedy for the leakage of ditch-water, which 
 is the original cause of the injury. 
 
 Composition of Alkali Salts. 
 
 Broadly speaking, it may be said that, the world over, alkali salts 
 consist of three chief ingredients, namely, common salt, glauber salt 
 (sulphate of soda), and salsoda or carbonate of soda. The latter 
 causes what is popularly known as " black alkali," from the black 
 spots or puddles seen on the surface of lands tainted with it, owing to 
 the dissolution of the soil humus; while the other salts, often together 
 with epsom salt, constitute " white alkali," which is known to be very 
 much milder in its effect on plants than the black. In most cases all 
 three are present, and all may be considered as practically valueless or 
 noxious to plant growth. With them, however, there are almost always 
 associated, in varying amounts, sulphate of potash, phosphate of soda, 
 and nitrate of soda, representing the three elements — potassium, phos- 
 phorus, and nitrogen — upon the presence of which in the soil, in avail- 
 able form, the welfare of our crops so essentially depends, and which we 
 aim to supply in fertilizers. The potash salt is usually present to the 
 extent of from 5 to 20 per cent of the total salts; phosphate, from a 
 fraction to as much as 4 per cent; the nitrate, from a fraction to as 
 much as 20 per cent. In black alkali the nitrate is usually low, the 
 phosphate high; in the white, the reverse is true. 
 
 It is thus clear that if we were to make a rule of reclaiming alkali 
 lands by leaching out the salts with abundance of irrigation water, we 
 would get rid not only of the noxious salts, but also of those ingredients 
 upon which productiveness primarily depends, and for which we pay 
 heavily in fertilizers. This is evidently to be avoided, if possible. 
 
 Summing up the conclusions from the foregoing observations and 
 considerations we find that — 
 
 (1) The amount of soluble salts in alkali soils is usually limited; 
 they are not ordinarily supplied in indefinite quantities from the bottom 
 water below. These salts have essentially been formed by weathering, 
 in the soil layer itself. 
 
 (2) The salts ordinarily move up and down within the upper 4 or 5 
 feet of the soil and subsoil, following the movement of the moisture; 
 descending in the rainy season to the limit of the annual moistening as 
 a maximum, and then reascending or not according as surface evapora- 
 tion may demand. At the end of the dry season, in untilled irrigated 
 land, practically the entire mass of salts may be within 6 or 8 inches 
 of the surface. 
 
— 14 - 
 
 (3) The injury to vegetation is caused mainly, sometimes wholly, 
 within a few inches of the surface, by the corrosion of the bark, usually 
 near the root crown. This corrosion is strongest when carbonate of soda 
 (salsoda) forms a large proportion of the salts; the soda then also dis- 
 solves the vegetable mold and causes blackish spots in the soil, popu- 
 larly known as black alkali. 
 
 (4) The injury caused by carbonate of soda is aggravated by its 
 action in puddling the soil so as to cause it to lose its flaky condition, 
 rendering it almost or quite untillable. It also tends to form in the 
 depths of the soil layer a tough hardpan, impervious to water, which 
 yields to neither plow, pick, nor crowbar, and renders drainage and 
 leaching impossible. Its presence is easily ascertained by means of a 
 pointed steel sounding rod. 
 
 (5) While alkali lands share with other soils of the arid region the 
 advantage of unusually high percentages of plant-food in the insoluble 
 form,* they also contain, alongside of the noxious salts, considerable 
 amounts of water-soluble plant-food. When, therefore, the action of the 
 noxious salts is done away with, they should be profusely and lastingly 
 productive; particularly as they are always naturally somewhat moist 
 in consequence of the attraction of moisture by the salts, and are there- 
 fore less liable to injury from drought than the same soils when free 
 from alkali. 
 
 Utilization and Reclamation op 1 Alkali Lands. 
 
 The most obvious mode of utilizing alkali lands is to occupy them 
 with useful plants that are not affected by the noxious salts. Unfortu- 
 nately, as has already been stated, but few such crops of general utility, 
 especially for the commercial and labor conditions of this country, have 
 as yet been found. Practically the most important problem is to render 
 these lands available for our ordinary cultures, by methods financially 
 possible. 
 
 Counteracting Evaporation. — Since evaporation of the soil moisture 
 at the surface is what brings the alkali salts to the level where the 
 main injury to plants occurs, it is obvious that evaporation should be 
 prevented as much as possible. This is the more important, as the 
 saving of soil moisture, and therefore of irrigation water, is attainable 
 by the same means. 
 
 Three methods for this purpose are usually practiced by farmers and 
 gardeners, viz, shading, mulching, and the maintenance of loose tilth 
 in the surface soil to such depth as may be required by the climatic 
 conditions. 
 
 *See Bulletin No. 3 of the U. S. Weather Bureau, 1892; Report California Station, 
 1894-5. 
 
— 15 — 
 
 As to mulching, it is already well recognized in the alkali regions of 
 California as an effective remedy in light cases. Fruit trees are fre- 
 quently thus protected, particularly while young, after which their 
 shade alone may (as in the case of low-trained orange trees) suffice to 
 prevent injury. The same often happens in the case of low- trained 
 vines, small fruit, and vegetables. Sanding of the surface to the depth 
 of several inches was among the first attempts in this direction; but 
 the necessity of cultivation, involving the renewal of the sand each 
 season, renders this a costly method. Straw, leaves, and manure have 
 been more successfully used; but even these, unless employed for the 
 purpose of fertilization, involve more expense and trouble than the sim- 
 ple maintenance of very loose tilth of the surface soil throughout the dry 
 season; a remedy which, of course, is equally applicable to field crops, 
 and in the case of some of these — e. g., cotton — is a necessary condition 
 of cultural success everywhere. The wide prevalence of "light" and 
 deep soils in the arid regions, from causes inherent in the climate 
 itself,* renders this condition of relatively easy fulfilment. 
 
 Diluting the Alkali Salts. — Aside, however, from the mere prevention 
 of surface evaporation, another favorable condition is realized by this 
 procedure, namely, the commingling of the heavily salt-charged surface 
 layers with the relatively nonalkaline subsoil. Since in the arid 
 regions the roots of all plants retire farther from the surface because of 
 the deadly drought and heat of summer, it is possible to cultivate 
 deeper than could safely be done with growing crops in humid climates. 
 Yet even here, the maxim of "deep preparation and shallow cultiva- 
 tion " is put into practice with advantage, only changing the measure- 
 ments of depth to correspond with the altered climatic conditions. 
 Thus, while in the eastern United States four inches is the accepted stand- 
 ard of depth for summer cultivation to preserve moisture without 
 injury to the roots, that depth must in the arid region frequently be 
 doubled in order to be effective, and will even then scarcely touch a 
 living root in orchards and vineyards in unirrigated land. 
 
 A glance at Fig. 1 (p. 7) will show the great advantage of extra 
 deep preparation in commingling the alkali salts accumulated near 
 the surface with the lower soil layers, diffusing the salts through 12 
 instead of 6 inches of soil mass. This will in very many cases suffice 
 to render the growth of ordinary crops possible if, by subsequent fre- 
 quent and thorough cultivation, surface evaporation, and with it the 
 reascent of the salts to the surface, is prevented. A striking example 
 of the efficiency pi this mode of procedure was given at the Tulare 
 substation, where a portion of a very bad alkali spot was trenched to 
 the depth of two feet, throwing the surface soil to the bottom. The spot 
 
 * See reference on preceding page. 
 
— 16 — 
 
 thus treated produced excellent wheat crops for a few years — the time 
 it took the alkali salts to reascend to the surface. 
 
 It should therefore be kept in mind that whatever else is done toward 
 reclamation, deep preparation and thorough cultivation must be regarded 
 as prime factors for the maintenance of production on all alkali lands. 
 
 The efficacy of shading, already referred to. is strikingly illustrated 
 in the case of some field crops which, when once established, will 
 thrive on fairly strong alkali soil, provided that a good thick "stand''' 
 has once been obtained. This is notably true of the great forage crop 
 of the arid region, alfalfa, or lucern. Its seed is extremely sensitive to 
 black alkali, and will decay in the ground unless protected against it. 
 But when once a full stand has been obtained, the field may endure for 
 many years without a sign of injury. Here two effects combine, viz, 
 the shading, and the evaporation through the deep roots and abundant 
 foliage, which alone prevents, in a large measure, the ascent of the 
 moisture to the surface. The case is then precisely parallel to that of 
 the natural soil (see Fig. 2), except that, as irrigation is practiced in 
 order to stimulate production, the sheet of alkali hardpan will be dis- 
 solved and its salts spread through the soil more evenly. The result is 
 that oftentimes, so soon as the alfalfa is taken off the ground and the 
 cultivation of other crops is attempted, an altogether unexpectedly large 
 amount of alkali comes to the surface and greatly impedes, if it does 
 not altogether prevent, the immediate planting of other crops. Shallow- 
 rooted annual crops that give but little shade, like the cereals, while 
 measurably impeding the rise of the salts during their growth, fre- 
 quently allow of enough rise after harvest to prevent reseeding the 
 following season. 
 
 Chemical Remedies. 
 
 Of the three sodium salts that usually constitute the bulk of " alkali" 
 only the carbonate of soda is susceptible of being materially changed 
 by any agent that can practically be applied to land. So far as we 
 know, the salt of sodium least injurious to ordinary vegetation is the 
 sulphate, commonly called glauber salt, which ordinarily forms the 
 chief ingredient of white alkali. Thus barley is capable of resisting 
 about five times more of the sulphate than of the carbonate, and quite 
 twice as much as of common salt. Since the maximum percentage that 
 can be resisted by plants varies materially with the kind of soil, it is 
 difficult to give exact figures save with respect to particular cases. For 
 the sandy loam of the Tulare substation the maximum for cereals may 
 be approximately stated to be one tenth of one per cent (0.1) for sal- 
 soda, a fourth of one per cent (0.25) for common salt, and from forty-five 
 to fifty one hundredths of one per cent (0.45-.50) for glauber salt, 
 within the first foot from the surface. For clay soils the tolerance is 
 markedly less, especially as regards the salsoda, since in their case the 
 
— 17 — 
 
 injurious effect on the tilling qualities of the soil, already referred to, 
 is superadded to the corrosive action of that salt; and in them, more- 
 over, accumulation at the surface is more pronounced. 
 
 Since, then, so little carbonate of soda suffices to render soils un- 
 cultivable, it frequently happens that its mere transformation into 
 the sulphate is sufficient to remove all stress from alkali. Gypsum 
 (land-plaster) is the cheap and effective agent to bring about this 
 transformation, provided water be also present. The amount required 
 per acre will, of course, vary with the amount of carbonate of soda in the 
 soil, all the way from a few hundred pounds to several tons in the case 
 of strong alkali spots. But it is not usually necessary to add the entire 
 quantity at once, provided that sufficient be used to neutralize the alkali 
 
 Fig. 5. Wheat growing in soil crusted with white alkali, originally a barren black 
 alkali spot. Tulare Experiment Substation. 
 
 near the surface, and enough time be allowed for the action to take 
 place. In very wet soils this may occur within a few days; in merely 
 damp soils, in the course of months; but usually the effect increases for 
 years, as the salts rise from below. For the complete neutralization of 
 each 1,000 pounds of carbonate of soda in the land, 1,630 pounds of 
 pure gypsum is required. But of the impure, 80-85% article as now 
 on the market in California, an even double quantity, or 2,000 pounds, 
 would be the proper dose. 
 
 The effect of gypsum on the black-alkali soil of Tulare substation 
 
 was to change a barren spot into a tract which produced a fine crop of 
 
 wheat, although the surface of the soil was covered with a crust of the 
 
 white alkali (sulphate of soda). This is shown in the accompanying 
 
 hotograph (Fig. 5). 
 
 2-b 128 
 
— 18 — 
 
 The effect of gypsum on black alkali land is often very striking, even 
 to the eye. The blackish puddles and spots disappear, because the 
 gypsum renders the dissolved humus insoluble and thus restores it to 
 the soil. The latter soon loses its hard, puddled condition and crum- 
 bles and bulges into a loose mass, into which water now soaks freely, 
 bringing up the previously depressed spots to the general level of the 
 land, and permitting free subdrainage. On the surface thus changed 
 seeds now germinate and grow without hindrance; and as the injury 
 from alkali occurs at or near the surface, it is usually best to simply 
 harrow in the plaster, leaving the water to carry it down in solution. 
 Soluble phosphates present are decomposed, so as to retain finely 
 divided but less soluble phosphates in the soil. 
 
 Trees and vines already planted may be temporarily protected from 
 the worst effects of the black alkali by surrounding the trunks with 
 gypsum or with earth abundantly mixed with it. Seeds may be simi- 
 larly protected in sowing, and young plants in planting. 
 
 It must not be forgotten that this beneficial change may go back- 
 ward if the land thus treated is permitted to be swamped by excess of 
 irrigation water, or otherwise. Under the same conditions, naturally 
 white alkali may turn black; and no amount of gypsum used can pre- 
 vent or undo this until the excess of water is drained off and the soil 
 allowed time for aeration. Thus while excessive irrigation is injurious 
 at all times in diminishing the depth of root-growth and the feeding 
 area of the plant, it is especially so when alkali is present. Of .course, 
 gypsum is of no benefit whatever on soils containing no salsoda, but 
 only glauber and common salt. 
 
 Stable Manure and Other Fertilizers. — Under the impression that 
 alkali land is poor in plant-food, farmers frequently try applications of 
 stable manure and other fertilizers. As a rule, these applications are 
 not only useless but even harmful. From their very mode of formation, 
 alkali soils are exceptionally rich in plant-food, so that the addition of 
 more can do no good. In the case of stable manure being used on 
 black alkali ground, a pungent odor of ammonia is given off whenever 
 the sun shines, and plants otherwise doing well are thus injured or 
 killed. When well plowed-in, stable manure will sometimes prevent 
 to some extent the rise of alkali by diminishing evaporation; but its 
 usefulness in that respect is readily replaced by good tillage. The 
 main benefit obtained is the addition of humus to soils that have been 
 whitened by alkali action. 
 
 Potash salts, especially kainit, are wholly useless and add to the 
 alkali trouble; potash is always abundantly present in alkali lands, 
 even in the water-soluble condition. Nitrates, also, are always present 
 in alkali soils in sufficient amounts for plant growth, sometimes to 
 
— 19 — 
 
 excess. Phosphates may sometimes be useful, but will rarely be needed 
 for some years. Greenmanuring, on the other hand, is a very desirable 
 improvement on all alkali lands. 
 
 Removing the Salts from the Soil. 
 
 In case the amount of salts in the soil should be so great that even 
 the change worked by gypsum is insufficient to render it available for 
 useful crops, the only remedy left is to remove the salts partially or 
 wholly from the land. Two chief methods are available for this purpose. 
 One is to remove the salts, with more or less earth, from the surface at 
 the end of the dry season, either by sweeping, or by means of a horse 
 scraper set so as to carry off a certain depth of soil. Thus sometimes 
 in a single season one third or one half of the total salts may be got 
 rid of, the loss of a few inches of surface soil being of little moment in 
 the deep soils of the arid region. The other method is to leach them 
 out of the soil into the country drainage, supplementing by irrigation 
 water what is left undone by the deficient rainfall. 
 
 It is not practicable, as many suppose, to wash the salts off the sur- 
 face by a rush of water, as they instantly soak into the ground at the 
 first touch. Nor is there any sensible relief from allowing the water to 
 stand on the land and then drawing it off; in this case also the salts 
 soak down ahead of the water, and the water standing on the surface 
 remains almost unchanged. In very pervious soils, and in the case of 
 white alkali, the washing-out can often be accomplished without special 
 provision for underdrainage, by leaving the water on the land suffi- 
 ciently long. But the laying of regular underdrains greatly accelerates 
 the work, and renders success certain. 
 
 An important exception, however, occurs in the case of black alkali 
 in most lands. In this case either the impervious hardpan or (in the 
 case of actual alkali spots) the impenetrability of the surface soil itself, 
 will render even underdrains ineffective unless the salsoda and its 
 effects on the soil are first destroyed by the use of gypsum, as above 
 detailed. This is not only necessary in order to render drainage and 
 leaching possible, but is also advisable in order to prevent the leaching- 
 out of the valuable humus and soluble phosphates, which are rendered 
 insoluble (but not unavailable to plants) by the action of the gypsum. 
 Wherever black alkali is found, therefore, the application of gypsum 
 should precede any and all other efforts toward reclamation. 
 
 Another method for diminishing the amount of alkali in the soil is 
 the cropping with plants that take up considerable amounts of salts. 
 In taking them into cultivation, it is advisable to remove entirely from 
 the land the salt growth that may naturally cover it, notably the 
 greasewoods (Allenrolfea, Sarcobatus), with their heavy percentages of 
 alkaline ash. Crop plants adapted to the same object are mentioned 
 farther on. 
 
— 20 — 
 Will It Pay to Reclaim Alkali Lands? 
 
 This is a question naturally asked when considering the nature and 
 expense of the operation involved, especially when the last resort — 
 underdraining and leaching— has to be adopted. 
 
 Those familiar with the alkali regions are aware how often the 
 occurrence of alkali spots interrupts the continuity of fields and 
 orchards, of which they form only a small part, but enough to mar their 
 aspect and cultivation. Their increase and expansion under irrigation 
 frequently render their reclamation the only alternative of absolute 
 abandonment of the investments and improvements made, and from 
 that point of view alone it is of no slight practical importance. More- 
 over, the occurrence of vast continuous stretches of alkali lands within 
 the otherwise most eligibly situated portions of the irrigation region 
 forms a strong incentive toward their utilization. 
 
 There is, however, a strong intrinsic reason pointing in the same 
 direction, namely, the almost invariably high and lasting productive- 
 ness of these lands when once rendered available to agriculture. This is 
 foreshadowed by the usually very heavy and luxuriant growth of native 
 plants around the margins of and between alkali spots (see Fig. 6); 
 that is, wherever the amount of injurious salts present is so small as not 
 to interfere with the utilization of the abundant store of plant-food which, 
 under the peculiar conditions of soil formation in arid climates, remains 
 in the land instead of being washed into the ocean. Extended com- 
 parative investigations of soil composition, as well as the experience of 
 thousands of years in the oldest settled countries of the world, demon- 
 strate this fact and show that so far from being in need of fertilization, 
 alkali lands possess extraordinary productive capacity whenever freed 
 from the injurious influence of the excess of useless salts left in the soil 
 in consequence of deficient rainfall. Alkali salts are actually scraped 
 up and carried to the cultivated fields in sacks in parts of Turkestan, 
 the peasants considering that " the salt is the life of the land." (Mid- 
 dendorf). 
 
 It does not, of course, follow that alkali lands are good lands for 
 farmers of limited means to settle upon. On the contrary, like most 
 other business enterprises, they require a certain amount of capital and 
 lapse of time to render them productive. They are not therefore a 
 proper investment for farmers or settlers of small means, dependent on 
 annual crops for their livelihood and unable to bring to bear upon these 
 soils the proper means for their reclamation; unless, indeed, local con- 
 ditions should enable them to use successfully some of the crops specially 
 adapted to alkali lands. 
 
-— 22 — 
 
 Crops Suitable for Alkali Lands. 
 
 As has already been stated, the search for generally available crops 
 that will thrive in strong, unreclaimed alkali land has not thus far 
 been very successful. It is true that cattle will nibble alkali grass 
 (Distichlis spicata), but will soon leave it for any dry feed that may be 
 within reach. The same is true of all the fleshy plants that grow on 
 the stronger alkali lands, and are known under the general designa- 
 tion of alkali weeds. When stock unaccustomed to it are forced by 
 hunger to feed on such vegetation to any considerable extent, disor- 
 dered digestion is apt to result; which in such ranges, however, is often 
 counteracted by feeding on aromatic or astringent antidotes, such as 
 the gray sagebrush and the more or less resinous herbage of plants of 
 the sunflower family. In the Great Basin region, lying between the 
 Sierra Nevada and the front range of the Rocky Mountains, there are, 
 aside from the grasses, numerous herbaceous and shrubby plants that 
 afford valuable pasturage for stock,* and some of these grow on mod- 
 erately strong alkali land; the same is true in California. It is quite 
 possible that some of these will be found to lend themselves to ready 
 propagation for culture purposes as well as they do for restocking the 
 ranges. But thus far none have found wider acceptance, probably 
 because their stiff branches and upright habit render them inconven- 
 ient to handle. It will require more extended experience and experi- 
 ment before any of these can be definitely adopted by farmers. 
 
 Experience in California indicates that in the more southerly portion 
 of the arid region the unpalatable native plants may be generally 
 replaced, even on the ranges, by one or more species of the Australian 
 saltbushes (Atriplex spp.), long ago recommended by Baron von 
 Mueller of Melbourne; of which one {A. semibaccata) has proved emi- 
 nently adapted to the climate and soil of California and is readily 
 eaten by all kinds of stock. The facility with which it is propagated, 
 its quick development, the large amount of feed yielded on a given 
 area, even in the strongest alkali land ordinarily found, and its thin, 
 flexible stems, permitting it to be handled very much like alfalfa, 
 seem to commend it specially to the farmer's consideration wherever 
 the climate will permit of its use. Its resistance to severe cold weather 
 has not yet been adequately tested. It is probable that other species, 
 now also under trial, will equally justify the recommendation given 
 them by the eminent botanist who first brought them into public 
 notice as promising forage plants. Most of the species have an upright, 
 shrubby habit, which adapts them rather to browsing than to use as a 
 
 * See Bulletin No. 16 of the Wyoming Experiment Station; also Bulletins Nos. 2 and 
 12 of the Division of Agrostology, and Farmers' Bulletin No. 108, TJ. S. Department of 
 Agriculture. 
 
— 23 — 
 
 forage crop. Among the best next to the semibaccata are the species 
 leptocarpa and halimoides, the former somewhat similar in habit to the 
 semibaccata but not so rapid a grower. A special bulletin on the salt- 
 bushes, Australian as well as native, has been published by this Sta- 
 tion and will be sent on request. 
 
 It is to be noted that since the saltbushes take up nearly one fifth of 
 their dry weight of ash ingredients*, largely common salt, the complete 
 removal from the land of a five-ton crop of saltbush hay will take away 
 nearly a ton of the alkali salts per acre. This will in the course of 
 some years be quite sufficient to reduce materially the saline contents 
 of the land, and wiU frequently render possible the culture of ordinary 
 crops. 
 
 Next to the saltbushes the Chilean plant Modiola decumbens (now 
 commonly known as modiola simply), of the mallow family, deserves 
 attention. Accidentally introduced as a weed with other seeds, by the 
 Kern County Land Company at Bakersfield, it attracted attention by 
 its persistence on alkali lands, and by the observation that cattle ate it 
 freely. It was then grown on a larger scale, and found to make accep- 
 table pasture where alfalfa could not be grown on account of alkali. It 
 is a trailing plant with medium-sized, roundish foliage, and roots freely 
 at the joints where they touch the ground. Unlike the saltbushes it is 
 therefore a formidable weed where it is not wanted; but as according to 
 our determinations it resists as much as 52,000 pounds of salts per acre, 
 even when 41,000 of these is common salt, it is likely to be useful in 
 many cases, particularly as an admixture to a saltbush diet for stock, 
 the more as it does not absorb as much salt as the latter. Owing to 
 the rooting habit of the stems, it is not as convenient to handle as the 
 semibaccata saltbush, nor, probably, will it yield as much fodder in a 
 season. It seems best adapted to pasturage. 
 
 Another forage plant which it may hereafter pay to propagate arti- 
 ficially on strong alkali land, is the tussock-grass (Sporobolus airoides), 
 of which a figure is given on page 37. Indicating as it usually does 
 when growing naturally, land too strongly impregnated to be reclaimable 
 at this time, but being freely eaten by stock, it seems worth while to 
 count it among the possible pasture grasses for land too strongly alka- 
 line to bear ordinary crops. Its seed can be abundantly gathered in its 
 native habitats, indicated below. 
 
 * Analyses made at the California station show 19.37 per cent of ash in the air-dry 
 matter of Australian saltbush. (See California Sta. Bui. 105; E. S. R., vol. 6, p. 718.) 
 Analyses of Russian thistle have been reported showing over 20 per cent of ash in dry 
 matter. (See Minnesota Sta. Bui. 34; Iowa Sta. Bui. 26; E. S. R., vol. 6, pp. 552, 553.) 
 
— 24 — 
 
 Amount of Salts Compatible with Ordinary Crops. 
 
 Since the amount of alkali that reaches the surface layer is largely- 
 dependent upon the varying conditions of rainfall or irrigation and 
 surface evaporation, it is difficult to foresee to what extent that 
 accumulation may go, unless we & know the total amount of salts present 
 that may be called into action. This can be ascertained by a summa- 
 tion of the results obtained and shown in the above diagrams for each 
 layer, but more readily by the examination of one sample representing 
 the average of the entire soil column of 4 feet. By calculating the 
 figures so obtained to an acre of ground, we can at least approximate 
 the limits within or beyond which crops will succeed or perish. 
 
 Grasses. — Applying this procedure to the cases investigated at the 
 Tulare substation, and estimating the weight of the soil per acre-foot at 
 4,000,000 pounds, we find for the land on which barley refused to grow 
 the figure 32,480 pounds of total salts per acre, corresponding to 0.203 
 per cent; while for the land on which barley gave a full crop we find 
 25,440 pounds, equivalent to 0.159 per cent for the whole soil column 
 of 4 feet. It thus appears that for barley the limits of tolerance lie 
 between the above two figures, which might, of course, have been 
 obtained equally well from an average sample of the 4-foot column by 
 making a single analysis. It should be noted that in this case a full 
 crop of barley was grown even when the alkali consisted of fully one 
 half of the noxious carbonate of soda, proving that it is not necessary 
 in every case to neutralize the entire amount of that salt by means of 
 gypsum, which in the present case would have required about 9i tons 
 of gypsum per acre — a prohibitory expenditure. 
 
 Rye appears to be about like barley in its tolerance of alkali salts; 
 while wheat is somewhat more sensitive. In fact, the superficial rooting 
 and fine fibrous roots of the true grasses render them, as a whole, rather 
 sensitive to alkali salts; yet there are a number of the perennial kinds 
 whose thick roots and deeper rooting render them measurably resistant. 
 Aside from the alkali grass proper (Distichlis), the so-called rye grass 
 of the Northwest (Elymus condensatus) is probably, next to the tussock- 
 grass, the most resistant species among the wild grasses. Its southern 
 form, with several, others not positively identified, occupy largely the 
 milder alkali lands of Southern California, such as the low lands near 
 Chino producing choice sugar beets on a close-textured silty loam. 
 
 While maize is rather sensitive, and fails on even slightly alkaline 
 lands, Egyptian corn and other sorghums, rooting somewhat deeper, 
 and having stout roots, do well on mild alkali soils of the white class. 
 The same appears to be true of some of the stout-rooted millets, such 
 as barnyard grass (Panicum crus-galli), of which the variety (?) muti- 
 
— 25 — 
 
 cum is reported to succeed well in neutral alkali land. One of the most 
 successful grasses on the light alkali lands near Chino, where most of 
 the commonly cultivated kinds fail, was a near relative of the barnyard 
 grass, the Eleusine coracana, which produces heavy crops of a millet- 
 like grain much relished by poultry and also by stock. This grass (of 
 which seed can be obtained from the Station) has succeeded all over 
 the ground whose alkali content ranges up to 12,000 pounds per acre. 
 Next to this, in point of success, were the pearl millet (Pennisetum 
 typhoideum) and teosinte, Hungarian brome grass, and Japanese millet, 
 on land containing about 9,000 pounds of salts per acre. The loliums, 
 including the darnel (" California cheat"), and the Australian and 
 Italian ray ("rye") grasses, succeed fairly on land containing as much as 
 6,000 pounds of (white) salts. Most other cultivated grasses failed 
 conspicuously alongside of these. It must be remembered that in more 
 loose-textured, sandy lands than those in which these tests were made, 
 the above figures for tolerance would probably be increased by 30 per 
 cent or more. 
 
 Doubtless some of the indigenous grasses of the interior plateau 
 region and the great plains east of the Rocky Mountains, such as the 
 buffalo and grama grasses, as well as several of the wheat grasses 
 (Agropyron) and bunch grasses (Festuca, Poa, Stipa, etc.) will prove 
 resistant to larger proportions of alkali than the meadow and pasture 
 grasses of the regions of summer rains. 
 
 Legumes. — Both the natural growth of alkali lands and experimental 
 tests seem to show that this entire family (peas, beans, clovers, etc.) 
 are among the more sensitive and least available wherever black alkali 
 exists, while fairly tolerant of the white (neutral) salts. Apparently a 
 very little salsoda suffices to destroy the tubercle-forming organisms that 
 are so important a medium of nitrogen-nutrition in these plants. Alfalfa, 
 with its hard, stout, and long taproot, seems to resist best of all these 
 plants, excepting the melilots. As a general thing, taprooted plants, 
 when once established, resist best, for the obvious reason that the main 
 mass of their feeding roots reaches below the danger level. Another favor- 
 ing condition, already alluded to, is heavy foliage and consequent shad- 
 ing of the ground; alfalfa happens to combine both of these advantages. 
 There has been some difficulty in obtaining a full stand of alfalfa in the 
 portion of the Chino tract containing from 4,000 to 6,000 pounds of alkali 
 salts per acre; but once obtained it has done very well. The only other 
 plant of this family that succeeds well on this land, and even (at Tulare) 
 on soil considerably stronger (probably between 20,000 and 30,000 
 pounds) are the two melilots, M. indica and alba; the latter (the 
 Bokhara clover) is a forage plant of no mean value in moist climates, 
 but somewhat restricted in its use in California because of the very high 
 aroma it develops, especially in alkali lands; so that stock will eat only 
 
— 26 — 
 
 limited amounts, best when intermixed with other forage, such as the 
 saltbushes. The yellow melilot is highly recommended by the Arizona 
 station as a greenmanure plant for winter growth; but in this State it 
 is a summer-growing plant only, and is refused by stock. Very few 
 plants belonging to this famity are naturally found on alkali lands, and 
 attempts to grow them, even where only glauber salt is present, have 
 been but very moderately successful. The salts seem to retard or even 
 prevent the formation of the tubercles useful for nitrogen absorption; 
 and for most of the legumes the limit of full success seems to lie between 
 3,000 and 4,000 pounds to the acre. 
 
 Weeds. — Like the legumes, wild plants of the mustard family are rare 
 on alkali lands; and correspondingly, the cultivated mustard, kale, rape, 
 etc., fail even on land quite weak in alkali. Their limit of tolerance 
 seems to lie near 4,000 to 5,000 pounds per acre of even white salts. 
 
 Several of the hardiest of the native "alkali weeds" belong to the sun- 
 flower family, and the common wild sunflowers (Helianthus californicus 
 and H. annuus) are common on lands pretty strongly alkaline. Cor- 
 respondingly, the " Jerusalem artichoke," itself a sunflower, is among 
 the available crops on moderately strong alkali soils; and so, doubtless, 
 are other members of the same relationship not yet tested, such as the 
 true artichoke, salsify, etc. Chicory, belonging to the same family, 
 yielded roots at the rate of 12 tons per acre, on land on the Chino tract 
 containing about 8,000 pounds of salts per acre. 
 
 Root Crops. — It seems to be generally true that root crops suffer in 
 quality, however satisfactory may be the quantity harvested on lands 
 rich in salts, and especially in chlorids (common salt). It was noted at 
 the Tulare substation that the tubers of the artichoke were inclined to 
 be "squashy" in the stronger alkali land, and failed to keep well; the 
 same was true of potatoes, which were very watery; and also of turnips 
 and carrots. It is a fact well known in Europe, that potatoes manured 
 with kainit (chlorids of potassium and sodium) are unfit for the man- 
 ufacture of starch, and are generally of inferior quality. But this is 
 found not to be the case when, instead of the chlorids, the sulphate is 
 used; hence the advice, often repeated by this Station, that farmers 
 desiring to use potash fertilizers should call for the " high-grade sul- 
 phate" instead of the cheaper kainit, which adds to the injurious salts 
 already so commonly present in California lowland soils. 
 
 The common beet (including the mangel-wurzel) is known to succeed 
 well on saline seashore lands, and it maintains its reputation on alkali 
 lands also. Being specially tolerant of common salt, it may be grown 
 where other crops fail on this account; but the roots so grown are 
 strongly charged with common salt, and have, as is well known, been 
 
— 27 — 
 
 used for the purpose of removing excess of the same from marsh lands. 
 Such roots are wholly unfit for sugar-making. 
 
 It is quite otherwise with glauber salt (sodium sulphate); and as 
 this is usually predominant in alkali lands, either before or after the 
 gypsum treatment, this fact is of great importance, for it permits of the 
 successful growing of the sugar beet; as has been abundantly proved at 
 the Chino ranch, where land containing as much as 12,000 pounds of 
 salts, mostly this compound, has yielded roots of very high grade both 
 as to sugar percentage and purity. 
 
 Asparagus is another crop which bears considerable amounts of com- 
 mon salt as well as of glauber salt; but not of salsoda, which must 
 first be transformed by the use of gypsum. 
 
 Rhubarb was a conspicuous failure in even the weak alkali lands of 
 the Chino tract. 
 
 Textile Plants. — Japanese hemp seemed to have a hard struggle 
 with the alkali while young, but at the end of the season stood 8 feet 
 high. The ramie plant, also, will bear moderately strong alkali, appar- 
 ently somewhat over 12,000 pounds per acre. Flax has not been tested 
 in cultivation; but its wide distribution all over the States of Oregon 
 and Washington would seem to indicate that it is not very sensitive. 
 Another textile plant, the Indian mallow (Abutilon avicennm), was 
 found to fail on the Chino alkali soil. 
 
 Grapevines. — The Vitis vinifera is quite tolerant of white or neutral 
 alkali salts, and will resist even a moderate amount of the black so 
 long as no hardpan is allowed to form. At the Tulare substation, it 
 was found that grapevines did well in sandy land containing 35,230 
 pounds of alkali salts, of which one half was glauber salt, 9,640 pounds 
 carbonate of soda, 7,550 pounds common salt, and 750 pounds nitrate of 
 soda. They were badly distressed where, of a total of 37,020 pounds of 
 alkali salts, 25,620 pounds was carbonate of soda; while where the 
 vines had died out, there was found a total of 73,930 pounds, with 
 37,280 pounds of carbonate. The European vine, then, is considerably 
 more resistant of alkali, even in its worst (black) form, than barley 
 and rye; and it seems likely that the native grapevines of the Pacific 
 Coast, Calif ornica and Arizonica, would resist even better; a point still 
 under experiment. 
 
 Experience, however, has shown that vines rapidly succumb when by 
 excessive irrigation the bottom water is allowed to rise, increasing the 
 amount of alkali salts near the surface and shallowing the soil at their 
 disposal. Such over-irrigation has been a fruitful cause of injury to 
 vineyards in the Fresno region, and would doubtless if practiced kill 
 most of the vines at Tulare substation which are now flourishing. In 
 such cases sometimes the formation of hardpan is followed by that of a 
 
— 28 — 
 
 concentrated alkaline solution above it, strong enough to corrode the 
 roots themselves, and not only killing the vines, but rendering the land 
 unfit for any agricultural use whatsoever. The swamping of alkali 
 lands, whether of the white or black kind, is not only fatal to their 
 present productiveness, but, on account of the strong chemical action 
 thus induced, greatly jeopardizes their future usefulness. Many costly 
 investments in orchards and vineyards have thus been rendered unpro- 
 ductive, or have even become a total loss. 
 
 Citrus Trees. — These are on the whole rather sensitive to alkali, 
 especially while young; so that it is often difficult to obtain a stand even 
 when, later on, the feeding roots descend beyond the reach of injury. 
 In the close-textured lands of Chino, young trees hardly maintained 
 life with more than 5,000 pounds of total salts. Common salt seems to 
 be particularly injurious; near Riverside, full-grown trees perished 
 under the influence of bottom water containing 0.25 per cent or 146 
 grains of salt per gallon, which impregnated the ground; corresponding 
 to about 9,000 pounds per acre in four feet. 
 
 In the sandy loam lands near Corona, trees eight years old suffered 
 severely when by irrigation with alkali water the alkali content of the 
 land reached 11,000 pounds per acre; as illustrated in Plates 7 and 8, 
 pages 32 and 33. At another point in the same region, two representa- 
 tive trees were selected for comparison, five rows apart on land absolutely 
 identical; one of these retained its leaves, though suffering, the other 
 was completely leafless. The leaching of the alkali to the depth of 4 feet 
 gave the following results, calculated to pounds per acre: 
 
 Sulphates. Carbonates. Chlorids. Total. 
 
 Poortree 4,720 1,680 2,520 8,920 
 
 Better tree _ 4,120 2,360 720 7,200 
 
 Here it is apparently the excess of common salt to which the differ- 
 ence is due, and this despite the higher content of carbonate of soda in 
 the soil bearing the better tree. 
 
 On the other hand, at the Tulare substation, orange trees (sour stock) 
 maintain vigorous growth and good bearing in a very sandy tract 
 which to the depth of 7 feet showed an aggregate content of 26,840 
 pounds of salts (or 22,780 to 4 feet depth); but which is never irri- 
 gated. (See diagram, page 10.) The salts in this case consist wholly 
 of sulphate and carbonate of soda in the ratio of 54 to 42, implying 
 the presence of nearly 12,000 pounds of salsoda within reach of the 
 tree roots; yet in the absence of common salt, no perceptible injury or 
 even stress upon the trees has been noted. 
 
 In view of these facts, it seems that common salt is the portion of 
 alkali by far most injurious to citrus trees, and that great care should 
 be taken in the use of irrigation waters to exclude those charged with 
 
— 29 — 
 
 common salt; also, to avoid locating citrus orchards where common 
 salt pre-exists in the land. 
 
 Deciduous Orchard Trees. — Of these, strangely enough, the almond 
 seems to resist best. The peach is more sensitive; the apricot does fairly. 
 Plum trees as such are nearly as resistant as peaches, but sometimes sud- 
 denly begin to fail when beginning to bear; the fruit appears normal on 
 the outside for a time, but the pit fails to form, being sometimes flattened 
 out like a piece of pasteboard; and the fruit fails to mature. Apples 
 are rather sensitive; pears considerably less so, doing well even when 
 the outside bark around the root crown is blackened by the alkali. The 
 olive is quite resistant; the fig less so. The English walnut resents 
 even a slight taint of black alkali, but is fairly tolerant of "white" 
 salts, as is shown in the peculiarly suitable light loam soils on the 
 lower Santa Clara River, in Ventura County. 
 
 Figures for the limits of alkali tolerance in the case of the deciduous 
 orchard trees have not yet been closely determined, owing to the 
 difficulties inherent in the differences of root penetration in the several 
 soils and localities. On the ten-acre tract near Chino, therefore on 
 a rather close-textured soil, apple trees have done very well on land 
 containing one fourth of one per cent of ("white") salts, or between 
 10,000 and 11,000 pounds per acre. On similar soil, the quince appears 
 to be perfectly at home. 
 
 Timber and Shade Trees. — Of trees suitable for alkali lands, two native 
 ones call for mention. One is the California white or valley oak ( Quercus 
 lobata), which forms a dense forest of large trees on the delta lands of 
 the Kaweah River in California, and is found scatteringly all over the 
 San Joaquin Valley (see frontispiece). Unfortunately, this tree does not 
 supply timber valuable for aught but firewood or fence posts, being 
 quite brittle. The native cottonwoods, while somewhat retarded and 
 dwarfed in their growth in strong alkali, are quite tolerant of the white 
 salts, especially of glauber salt. 
 
 Of other trees, the oriental plane, or sycamore, and the black locust, 
 have proved the most resistant in the alkali lands of the San Joaquin 
 Valley; and the former being a very desirable shade tree, it should be 
 widely used throughout the regions where alkali prevails more or less. 
 The ailantus is about equally resistant, and but for the evil odor of its 
 flowers, deserves strong commendation. Of the eucalypts, the narrow- 
 leaved Eucalyptus amygdalina (one of the "red gums") seems to be 
 least sensitive, and in some cases has grown as rapidly as anywhere. 
 The E. rostrata, as well as the pink-flowered variety of E. sideroxylon, 
 are now doing about as well as the amygdalina at Tulare, where at first 
 they seemed to suffer. The common blue gum, E. globulus, is much 
 more sensitive. 
 
— 30 - 
 
 Of the acacias, the tall-growing A, melanoxylon (" black acacia ") 
 resists pretty strong alkali, even on stiff soil; as can be seen at Tulare 
 and Bakersfield, where there are trees nearly two feet in diameter. The 
 beautiful A. lophantha (Albizzia) has in plantings made along the San 
 Joaquin Valley Railroad shown considerable resistance, likewise; but 
 it is quite sensitive to frost. 
 
 One of the "Australian pines, Casuarina equisetifolia" was transplanted 
 experimentally on station grounds of the Valley Railroad from the 
 Chico forestry substation, and a number are growing very well in alkali 
 lands. This tree is credited by Maiden with being tolerant of "saline 
 soil." Doubtless many others of the Casuarina tribe will be found sim- 
 ilarly resistant. 
 
 Of Eastern trees, the elms have done fairly well, but the tulip tree, 
 the linden, the English oak, and most other trees of the Atlantic States, 
 become stunted. Among those doing fairly well is the honey locust; 
 but its thorns and imperfect shade render it not very desirable. 
 
 The California maple {Acer macrophyllum) and box elder (Negundo 
 calif ornica) have done fairly well in the lighter alkali lands at Tulare. 
 
 A most remarkably alkali-resistant shrub or small tree is the pretty 
 Koelreuteria paniculata, which at Tulare is growing in some of the 
 strongest alkali soil of the tract. Unfortunately it is available mainly 
 for ornamental purposes; its wood, while small, is very hard and makes 
 excellent fuel. 
 
 Irrigation with Saline Waters. 
 
 It would hardly seem necessary to emphasize specially the danger 
 incurred in irrigation with waters containing unusual amounts of solu- 
 ble salts; since ordinary common sense clearly indicates the impropriety 
 of increasing the saline contents of soils already charged with them, by 
 the evaporation, year after year, of large masses of saline water. Yet 
 experience has shown that the eagerness to utilize for irrigation whatever 
 water happens to be convenient to good lands, often overcomes both 
 that sense, and the warning given by the published analyses of such 
 waters. Without specifiying localities, it may be said that great injury 
 has already been done in California by the disregard of obviously 
 needful caution in this respect. The very slight taste possessed by 
 glauber salt and salsoda does not adequately indicate their presence 
 even when in injurious amounts; so that frequently a chemical test of 
 the waters is the only definite guide. A few general rules, however, 
 will help to enable the irrigator to determine whether or not such 
 examination is called for. 
 
 It may be taken for granted that the waters of all lakes having no 
 regular outflow are unfit for regular irrigation use; since they must needs 
 contain all the accumulations of salts from the secular evaporation of 
 the waters that flow into them. 
 
— 31 — 
 
 The plates annexed exhibit the cultural results of several years' 
 irrigation with the waters of Lake Elsinore, Riverside County, as com- 
 pared with the growth of orange trees on the same land, but irrigated 
 with artesian water. Lake Elsinore is fed by the San Jacinto River, 
 and in wet years sometimes overflows for a few weeks into Temescal 
 Creek. Thus its saline content varies somewhat, from about 80 to over 
 100 grains per gallon, of salts containing three-fifths of common salt 
 and one-fifth each of glauber salt and carbonate of soda. The latter, 
 as already stated, tends to form a hardpan in the subsoil, and such 
 hardpan was actually formed where the water was used; and afterward 
 prevented its proper penetration, so that the trees suffered from dryness 
 of their lower roots, while damaged by the alkali salts near the surface. 
 As mentioned before, experience elsewhere has shown that citrus trees 
 are especially sensitive to common salt. 
 
 The investigations made by the Station have, moreover, shown that 
 aside from the frequently saline character of the well and even the 
 artesian waters of the petroleum-bearing region of the State in the coast 
 ranges, the streams of that region, especially the smaller ones, are some- 
 times too strongly charged with "alkali" (in this case largely the 
 sulphates of soda and magnesia) to be suitable either for irrigation or 
 domestic use. Toward the end of the dry season, even the larger streams 
 of the southern coast ranges, with their diminished flow, sometimes show 
 an excess of salts. This seems also to be true of the San Jacinto River, 
 which feeds Elsinore Lake. 
 
 The waters flowing from the Sierra Madre, south of the Tehachapi 
 range, are throughout of excellent quality for irrigation purposes; as 
 are all those flowing from the Sierra Nevada. The same is true of the 
 artesian waters of the valley of Southern California, from Los Angeles 
 east to Redlands, and of all the deeper borings of the Antelope Valley. 
 
 In the Great Valley, the artesian waters vary greatly in quality. 
 Those of Kern and Tulare counties are mostly good, sometimes excep- 
 tionally so, as in the case of the water-supply of Tulare City. It is only 
 the shallower borings, near the borders of Tulare Lake, that some waters 
 strongly charged with carbonate of soda or other salts have been found. 
 From Fresno and Merced we have few data as yet; but it seems that 
 north of a line drawn from northeastern Stanislaus via Tracy to Point 
 of Timber, saline waters, sometimes accompanied by some gas, occur at 
 certain levels. But the deep wells bored at Stockton and Sacramento, 
 and northward, have good potable water. 
 
 Limits of Saline Contents. — Unfortunately it is not easy to give absolute 
 rules in regard to the exact figures that constitute an excess of salts 
 for irrigation purposes, since not only the composition of the salts, 
 but also the nature of the land to be irrigated, and the frequency of 
 irrigation required, must be taken into consideration. 
 

 3 ® 
 
 5 ° 
 
#k 
 
 3— B 1 
 
 (33) 
 
— 34 — 
 
 Broadly speaking, the extreme limits of mineral content usually- 
 assigned for potable waters, viz, 40 grains per gallon, also applies to 
 irrigation waters. Yet it sometimes happens that all or most of the 
 solid content is gypsum and epsbm salt; when only a large excess of 
 the latter would constitute a bar to irrigation use. When, on the con- 
 trary, a large proportion of the solids consists of carbonate of soda or 
 of common salt, even a smaller proportion of salts than 40 grains 
 might preclude its regular use, depending upon the nature of the soil 
 to be irrigated. For in a clay loam, or a heavy adobe, not only do the 
 salts accumulate nearer to the surface, but the subdrainage being slow 
 and imperfect (unless underdrained), it becomes difficult or impossible 
 to wash out the saline accumulations from time to time, as is feasible 
 in sandy lands. In these, moreover, as already stated, the alkali never 
 becomes as concentrated near the surface as in heavier soils. Again, 
 where hardpan exists in sandy land, saline irrigation-water soon 
 saturates the soil mass above it with salts. 
 
 During the two dry seasons just past saline waters have frequently 
 been used, exceptionally, in order to save trees threatened with death 
 from drought. The Station has even advised that this should be done, 
 with the proviso that the salts so introduced must be washed into the sub- 
 drainage by heavy irrigation, whenever practicable, even if the same 
 saline water should have to be used for the purpose. For few such 
 waters are sufficiently strong to injure vegetation until concentrated by 
 evaporation; as can be seen from the vegetation growing close to the 
 margins of alkaline lakes, with its roots immersed in the water. 
 
 The irrigator can determine for himself whether or not his water is 
 of doubtful character, by evaporating a tablespoonful, or more, in a clean 
 silver spoon (avoiding boiling). If the dry residue should form simply 
 a thin, powdery-looking film on the polished metal, he may be assured 
 that the water is all right. If, on the other hand, an obvious saline 
 crust should remain, which will redissolve in water, he should either 
 have an analysis made, or use the water in such a manner as to remove 
 the accumulated salts from time to time by washing them into the 
 subdrainage, if the nature of the soil permits. A very abundant use of 
 such ivaters is then preferable to a sparring one; but the user should 
 assure himself that it really penetrates, for otherwise, especially in case 
 much carbonate of soda is present, a dense hardpan may be formed that 
 will allow the trees to perish from drought despite all the water running 
 in the irrigation furrows. A pointed steel probe, three-sixteenths of an 
 inch square, provided with a cross-handle, like a hand auger, ought 
 to be among the tools of every farmer for such tests of his subsoil. 
 No farmer in the arid region can afford to be ignorant of the nature 
 of the substrata within which the bulk of the roots of his crops must 
 vegetate. 
 
35 
 
 Reclaimable and Irreclaimable Alkali Lands as Distinguished by 
 Their Natural Vegetation. 
 
 While, as shown above, the adaptation or non-adaptation of par- 
 ticular alkali lands to certain cultures may be determined by sampling 
 the soil and subjecting the leachings to chemical analysis, it is obvi- 
 ously desirable that some other means, if possible available to the 
 farmer himself, should be found to determine the reclaimability and 
 adaptation of such lands for general or special cultures. 
 
 The natural plant growth seems to afford such means, both as 
 regards the quality and quantity of the saline ingredients. The most 
 superficial observation shows that certain plants indicate extremely 
 strong alkali lands where they occupy the ground alone; others indi- 
 cate preeminently the presence of common salt; the presence or absence 
 of still others form definite or probable indications of reclaimability or 
 non-reclaimability. Many such characteristic plants are well known 
 to and readily recognized by the farmers of the alkali districts. 
 "Alkali weeds" are commonly talked about almost everywhere; but the 
 meaning of this term — i. e., the kind of plant designated thereby— 
 varies materially from place to place, according to climate as well as to 
 the quality of the soil. Yet if these characteristic plants could be 
 definitely observed, described, and named, while also ascertaining the 
 amount and kind of alkali they indicate as existing in the land, lists 
 could be formed for the several districts, which would indicate, in a 
 manner intelligible to the farmer himself, the kind and degree of 
 impregnation with which he would have to deal in the reclamation 
 work, thus enabling him to go to work on the basis of his own judg- 
 ment, without previous reference to this Station. 
 
 The carrying-out of such a plan involves, obviously, a very large 
 amount of botanical as well as chemical work, which cannot be accom- 
 plished within a few seasons; and, in view of the wide differences in 
 the vegetation of the several alkali regions of the State, the same work 
 will have to be repeated to a certain extent in each of these regions. 
 The object to be achieved is, however, of such high practical impor- 
 tance — an importance not remotely appreciated as yet by those not 
 familiar with the enormous extent of otherwise desirable lands in this 
 State that are more or less tainted with alkali — as to deserve the 
 expenditure upon it of a large amount of work as promptly as possible. 
 
 The extreme limitation of funds under which the Agricultural Col- 
 lege, together with the University as a whole, has been suffering for 
 some years past, has thus far restricted the scope of these researches 
 very closely, both geographically and otherwise. It is hoped that in 
 the future, a close comparison of the native vegetation with the chem- 
 ical determination of the quantity and kind of alkali corresponding to 
 
— 36 — 
 
 certain plants, or groups of plants, naturally occurring on the land, 
 may enable us to come to a sufficiently close estimate of the nature 
 and capabilities of the latter from the native vegetation alone, or with 
 the aid of test plants purposely grown. But before entering upon this 
 complex problem, it has been thought best to determine, first of all, 
 what lands may for present economic conditions be considered irre- 
 claimable, because their improvement would involve an expense out of 
 proportion with present land values. So far as large areas are con- 
 cerned, this may probably be considered to be the case when tile under- 
 drainage is required in order to wash out the salts; while of course 
 smaller tracts, which interrupt the cultivation of fields, may frequently 
 justify the laying of a few drain lines required to render them cultiva- 
 ble with the rest of the land. 
 
 As stated in the report of this Station for 1895-7, the field work of 
 this investigation, both botanical and in the collection of the corre- 
 sponding soil samples, has been done by Mr. Joseph Burtt Davy, 
 Assistant Botanist to the Station, who also supplies the notes accom- 
 panying the same; while the laboratory work for the determination of 
 the amounts and kinds of salts present in the several cases has been 
 carried out by Prof. R. H. Loughridge. 
 
 The plants hereinafter mentioned, and figured for the benefit of the 
 great majority of readers who would fail to recognize them from the 
 botanical description alone, are then to be understood as indicating, 
 whenever they occupy the ground as an abundant and luxuriant growth, 
 that such land is irreclaimable for ordinary crops, unless underdrained 
 for the purpose of washing out surplus salts. The occurrence merely 
 of scattered, more or less stunted individuals of these plants, while 
 a sure indication of the presence of alkali salts, does not necessarily 
 show that the land is irreclaimable. 
 
 The plants which may best serve as such indicators in California are 
 the following: 
 
 Tussock-grass (Sporobolus airoides, Torr.), Fig. 9; 
 
 Greasewood (Sarcobatus vermiculatus (Hook.) Torr.), Fig. 10; 
 
 Dwarf Samphire (Salicornia subterminalis, Parish, and other species), 
 
 Fig. 11; 
 
 Bushy Samphire (Allenrolfea occidentalis (Wats.) Ktze.), Fig. 12; 
 Saltwort (Suaeda Torreyana, Wats., and S. suffrutescens, Wats.), 
 Fig. 13; 
 Alkali-heath (Frankcnia grandifolia campestris, Gray), Fig. 14; 
 Cressa (Cressa c:etica truxillensis, Choisy), Fig. 15. 
 
37 — 
 
 TUSSOCK-GRASS* (Sporobolus airoides, Torr.); Fig. 9. 
 
 The three sets of samples of Tussock-grass soil which have been analyzed 
 show that the total amount of all salts present is in no case less than 
 49,000 pounds per acre, to a 
 depth of four feet, and that it 
 sometimes reaches the extraor- 
 dinarily high figure of 499,000 
 pounds. Of these amounts the 
 neutral salts (glauber salt and 
 common salt) are usually in the 
 heaviest proportion (glauber salt, 
 19,600 to 323,000 pounds per 
 acre ; common salt, 3,500 to 
 172,800); the corrosive salsoda 
 varying from 3,000 to 44,000 
 pounds. —Tussock-grass appar- 
 ently cannot persist in ground 
 which is periodically flooded. It 
 is of special importance because 
 it is an acceptable forage for 
 stock. 
 
 Tussock-grass is a prevalent 
 alkali-indicator in the hot, arid 
 portions of the interior, from the 
 upper San Joaquin Valley, the 
 Mojave Desert, and southward; 
 also through southern Nevada 
 and Utah as far east as Kansas 
 and Nebraska. In the San Joa- 
 quin Valley we have not found it FlG 9 tussock-okas*-^^ abides, Torr- 
 
 farther north than the Tulare (From Division of Agrostology, U. S. Dept. Agr.) 
 
 plains, although east of the Sierra it occurs near Reno. Coville observes 
 that in the Death Valley region "it is confined principally to altitudes 
 below 1,000 meters" (3,280 feet). Hillman, however, reports it from near 
 Reno, Nevada, at an altitude which cannot be much less than 4,500 feet. 
 As we have received requests for precise information as to the localities 
 in which this grass grows, from persons desiring to obtain seed for trial, 
 the following list is given: Tulare plains, a few miles southeast of 
 Tulare; a few miles south of Bakersfield; in the Antelope Valley; along 
 the road from Rosamond to Lancaster, and in alkali sinks about the 
 Leonis Valley between Lancaster and Elizabeth Lake. It is reported 
 by Coville from Death Valley, Pahrump Valley, Resting-Springs Valley? 
 
 * So-called because it grows in large clumps or tussocks, which feature unfortunately 
 is not indicated in the illustration. 
 
38 — 
 
 Owens River Valley, and other points in the desert region southeast of 
 the Sierra Nevada. It is also recorded from near Barstow and other 
 points in San Bernardino County; in dry soils near Los Angeles, and 
 from San Diego County. 
 
 GREASEWOOD* (Sarcobatus v ermicu I 'atus (Hook) Torr.); Fig. 10. 
 
 Through the courteous cooperation of Prof. F. H. Hillman, Botanist to 
 the Nevada Agricultural Experiment Station at Reno, we have obtained 
 three series of samples of Greasewood soil from that vicinity. These sam- 
 
 Fig. 10. Greasewood (proper)— Sarcobatus vermicutatus (Hook) Torr. 
 
 A. Appearance of a branch when not in blossom. 
 
 B. Spiny branchlet from the same. 
 
 C. Branchlet bearing cones of male flowers. 
 
 D. Cone of male flowers enlarged. 
 
 E. Branch bearing fruits. 
 
 F. Cluster of fruits enlarged. 
 
 G. Vertical section through a fruit, showing the seed with its 
 
 curved embryo, (enlarged). 
 
 * This is the true Greasewood of the desert region east of the Sierra Nevada, and not 
 either of the plants known under that name in the San Joaquin Valley and in Southern 
 California. 
 
— 39 — 
 
 pies show that where the Greasewood shrubs are thinly scattered and 
 stunted in growth, the salt content per acre to the depth of three feet 
 is about 2,400 pounds, of which over one half consists of the corrosive 
 carbonates. Where a luxuriant growth occurs the total salts per acre 
 vary from 38,000 to 58,500 pounds, with 18,700 pounds of salsoda and 
 920 to 3,680 pounds of common salt; the relative percentage of the inju- 
 rious salsoda is thus invariably high. The common salt is low and the 
 neutral glauber salt is variable. This plant therefore always indicates 
 the presence of "black alkali." 
 
 Greasewood is distinctly a plant of the Great Basin, only reaching 
 California in the adjacent counties of Lassen. Alpine, Mono, and 
 northern Inyo. It is very abundant on the lower levels of Honey Lake 
 Valley. 
 
 DWARF SAMPHIRE (Salicornia subterminalis, Parish, and other species of 
 the interior) ; Fig. 11. 
 
 The two or three species of Dwarf Samphire which grow in the interior 
 valleys of the State are nowhere very abundant in those portions 
 
 Fig. 11. Dwarf Samphire— Salicornia subterminalis, Parish. 
 
— 40 — 
 
 of the alkali region which we have thus far investigated. Wherever the 
 species do occur, however, they are confined to such very strongly saline 
 soils that they may be considered valuable indicative plants. We have 
 as yet only one full set of samples of Dwarf Samphire soil. This shows 
 the total salt content to amount to 441,880 pounds per acre in a depth of 
 four feet. The neutral glauber salt amounts to 314,000 pounds, almost 
 as much as in Tussock-grass soil ; common salt up to 1 25,640 pounds, while 
 the salsoda varies from 2,200 to 12,000. We may consider this plant as 
 indicative of almost the highest percentage of common salt, glauber 
 salt, and total salts. Like the preceding species, it indicates "white" 
 salts in excessive amounts, and a subsoil too wet for the Australian 
 saltbush. 
 
 Salicornia subterminalis occurs in San Diego, Riverside, Los Angeles, 
 and Kern counties. S. herbacea (L.) is reported from Riverside County, 
 and from the margin of Tehachapi Lake, Kern County. S. mucronata 
 (Bigelow) occurs in San Diego County; and a fourth species is found 
 in the Antelope Valley, Los Angeles County; near Bakersfield, Kern 
 County; and at Byron Springs, Contra Costa County. These inland 
 species all differ materially in habit and botanical characters from the 
 one common in submerged salt marshes along the seashore, but all alike 
 indicate strongly saline soils. 
 
 BUSHY SAMPHIRE (Allenrolfea occidentalis (Wats.) Ktze.); Fig. 12. 
 
 This plant is locally called greasewood, but as this name is much more 
 commonly used for Sarcobatus vermiculatus, it seems best to call Allen- 
 rolfea "bushy samphire," as it closely resembles the true samphire {Sali- 
 cornia). 
 
 Bushy Samphire usually grows in low sinks, in soil which in winter 
 is excessively wet and in summer becomes a "dry bog." Wherever the 
 plant grows luxuriantly the salt content is invariably high, the total 
 salts varying from 327,000 pounds per acre, to a depth of three feet, to 
 494,520 pounds in four feet. The salts consist mainly of glauber and 
 common salts (a maximum of about 275,000 pounds of each); salsoda 
 varies from 2,360 to 4,800 pounds per acre. The percentage of common 
 salt and total salts is higher than for any other plant investigated, and the 
 glauber salt is almost proportionate. The areas over which this plant 
 grows must therefore be considered as among the most hopeless of alkali 
 lands, for although its salts are "white," submergence during winter 
 precludes the growth of Australian saltbush. 
 
 Bushy Samphire is a common plant in alkali soils in the upper San 
 Joaquin Valley, around Bakersfield and Delano; a few stunted bushes 
 occur near the margin of Tulare Lake, west of Tulare, but at that point 
 it appears to be dying out. It also occurs on the east slope of Liver- 
 more Pass, and in an alkali sink in a pocket of the hills at Byron 
 
Fig. 12. Bushy Samphire— AUenrolfea occidentalis (Wats.) Ktze. 
 [Called "Greasewood" in San Joaquin Valley.] 
 
— 42 — 
 
 Springs, Contra Costa County. In the Death Valley region the plant 
 appears to be very abundant, occupying an area considerably more 
 southern than what appears to be the southerly limit of Greasewood 
 (Sarcobatus). 
 
 SALTWORT (Suaeda Torreyana, Wats., S. suffrutescens, Wats., and perhaps 
 one other species); Fig. 13. 
 
 Samples of Saltwort soil from Bakersfield, Kern County, and Byron 
 Springs, Contra Costa County, taken to a depth of one foot and three 
 feet respectively, show that this plant grows luxuriantly in a soil con- 
 
 Fig. 13. Saltwort— Suaeda Torreyana, Wats. 
 
 taining 130,000 pounds of salts per acre in the first foot, and with 
 10,480 pounds of the noxious salsoda, and 39,760 pounds of common 
 salt in three feet ; while only a sparse growth is found on soils contain- 
 ing only 3,700 pounds of salts in three feet. It thus appears to indicate 
 a lower percentage of salsoda than does Greasewood, but a higher per- 
 centage than Bushy Samphire. Further investigation is necessary 
 to determine the exact relation of the different salts to the growth 
 of the plant, and as to whether carbonates always occur in large quantity; 
 but enough data have been gathered to show that a luxuriant growth 
 
43 
 
 of Saltwort indicates a soil practically irreclaimable except at the ex- 
 pense of leaching. 
 
 Suaeda Torreyana occurs in abundance in certain alkali soils near 
 Bakersfield, Kern County; in a large alkali sink near Colusa Junction, 
 Colusa County; in Honey Lake Valley, Lassen County; Antelope Valley, 
 Kern County; and in the vicinity of San Bernardino. Coville reports 
 having collected it at Lone Pine, Inyo County. The closely related 
 species, S. suffrutescens, only to be distinguished by an expert botanist, 
 occurs in abundance in the alkali soils of the Mojave Desert, Death 
 Valley, the Tulare plains, and near Bakersfield. The different species 
 of Saltwort grow in similar habitats, and it is probable that the condi- 
 tion of the soil is approximately the same for each species. It thus 
 indicates land that while not capable of bearing ordinary crops, will 
 probably allow the Australian saltbush to succeed, at least with the aid 
 of some gypsum. 
 
 ALKALI-HEATH (Frankenia grandifolia campestris, Gray) ; Fig. 14. 
 
 Alkali-heath is perhaps the most widely distributed of any of our 
 California alkali plants. Its perennial, deep-rooting habit of growth, 
 and flexible, somewhat wiry 
 rootstock, which enables it 
 to persist even in cultivated 
 ground, render it a valuable 
 plant as an alkali indicator. 
 The salt content where Al- 
 kali-heath grows luxuri- 
 antly is invariably high, 
 ranging from 64,000 to 
 282,000 pounds per acre; 
 salsoda varies from 680 to 
 19,590 pounds; common 
 salt ranges from 5,000 to 
 10,000 pounds. Such soils 
 would not be benefited by 
 the application of gypsum, 
 as the salts are already 
 
 largely in the neutral State. FlG - 14 - Alkali- he \TH.—Frankenia grandifolia campeotris, 
 
 Of useful plants only Salt- 
 bushes and Tussock-grass are likely to flourish in such lands. 
 
 While Alkali-heath is thus one of the most alkali-tolerant plants, it 
 is at the same time capable of growth with a minimum of salts (total 
 salts 3,700 pounds, salsoda 680 pounds). Where only a sparse growth 
 of this plant occurs, therefore, the land should not be condemned until 
 a chemical examination of the soil has been made. 
 
44 
 
 Alkali-heath is found on soils of very varying physical texture and 
 degrees of moisture; while on soils of uniform texture and moisture, but 
 differing in chemical composition, it varies with the varying salt- 
 content. 
 
 It has been found that Australian Saltbush (Atriplex semibaccata) 
 can be successfully grown on the Colusa County "goose lands," on soil 
 producing a medium crop of Alkali-heath; it remains to be shown 
 whether it will do equally well on soils producing a dense and luxuriant 
 growth of the same. 
 
 Alkali-heath is so widely distributed throughout the interior vallej^s 
 of California that it would be superfluous to give a list of the localities 
 in which it occurs. A closely related form is found in salt marshes 
 along the coast, differing from that of the interior principally in its 
 much broader leaves. 
 
 CRESSA (Cressa cretica truxillensis, Choisy); Fig. 15. 
 
 Cressa soils show a low percentage of the noxious salsoda, but com- 
 paratively heavy total salts 
 ( 161,000 to 282,000 pounds per 
 acre.) Common salt varies 
 from 5,760 to 20,840 pounds 
 per acre in four feet. The 
 maximum is lower than in 
 the case of Alkali-heath, but 
 Cressa seems to be much more 
 closely restricted to strong 
 alkali than does the former 
 species. Cressa appears to be 
 as widely distributed through 
 the interior valleys of the State 
 as Alkali-heath. It is a cos- 
 mopolitan plant, occurring, as 
 its name indicates, on the Ion- 
 ian Isles, as well as in North 
 Africa, Syria, and in other 
 arid countries of the world. 
 
 Fl< 
 
 15. Cressa — Cressa cretica truxillensis, Choisy. 
 
 Relative Tolerance of the Different Species. 
 
 In order to determine the relative nature of the soils characterized 
 by each of the above-named plants, Mr. Davy has prepared the follow- 
 ing table, in which the column marked optimum shows, as nearly as 
 possible with our present knowledge of the subject, the condition of the 
 soil where each species grows in about equal luxuriance. For Saltwort 
 and Dwarf Samphire we have not yet been able to obtain as thoroughly 
 characteristic soil samples as could be desired, but we hope to be able to 
 do so during the coming season. 
 
- 45 — 
 
 It must be understood that the optimum indicates the condition under 
 which the plant has been found at its greatest luxuriance — where it is 
 evidently "at home" — ; whereas the maximum and minimum have 
 sometimes been obtained where the plants were more or less stunted in 
 growth and sparingly scattered over the ground. 
 
 Table Showing Maximum, Optimum, and Minimum of Salts Tolekated by Each of 
 the Several Alkali Plants. 
 
 Pounds Per Acre. 
 
 Optimum. 
 
 Maximum. 
 
 Minimum. 
 
 Bushy Samphire . 
 Dwarf Samphires. 
 
 Alkali-heath 
 
 Total Salts. 
 
 Cressa 
 
 Saltworts 
 
 Greasewood .. 
 Tussock-grass 
 
 Tussock-grass 
 Alkali-heath.. 
 
 Carbonates (Salsoda). 
 
 Greasewood . 
 
 Dwarf Samphires. 
 
 Saltworts 
 
 Cressa 
 
 Bushy Samphire . 
 
 Chlorids (Common salt). 
 
 Bushy Samphire 
 
 Dwarf Samphires 
 
 Saltworts 
 
 Cressa. 
 
 Alkali-heath 
 
 Tussock-grass 
 Greasewood _. 
 
 Sulphates (Glauber salt). 
 
 Dwarf Samphires. .j 
 
 Bushy Samphire 
 
 Cressa 
 
 Alkali-heath . 
 
 Saltworts 
 
 Greasewood . . 
 Tussock-grass 
 
 494,520 
 
 441,880 
 
 281,960) 
 
 64,300 I" 
 
 281,960 
 
 130,000 
 
 58,560 
 
 49,000 
 
 23,000 
 
 *19,590) 
 
 680 I 
 
 18,720 
 
 12,120 
 
 10,480 
 
 5,440 
 
 4,800 
 
 212,080 
 
 125,640 
 
 39,760 
 
 20,840 
 
 10,180) 
 
 5,760f 
 
 6,200 
 
 3,680 
 
 314,040 
 
 277,640 
 
 275,520 
 
 275,520) 
 
 34,530* 
 
 44,160 
 
 36,160 
 
 19,640 
 
 494,520 
 441,880 
 
 499,040 
 
 281,960 
 
 153,020 
 
 58,560 
 
 499,040 
 
 44,460 
 
 19,590 
 
 18,720 
 
 12,120 
 
 12,120 
 
 5,440 
 
 4,800 
 
 275,160 
 
 125,640 
 
 52,900 
 
 20,840 
 
 212,080 
 
 172,800 
 3,680 
 
 314,040 
 277,640 
 275,520 
 
 323,200 
 
 104,040 
 
 36,160 
 
 323,200 
 
 135,060 
 441,880 
 
 3,720 
 
 161,160 
 
 3,720 
 
 2,400 
 
 49,000 
 
 3,040 
 
 680 
 
 1,280 
 2,200 
 1,120 
 680 
 1,500 
 
 56,800 
 
 125,640 
 
 1,040 
 
 5,760 
 
 1,040 
 
 3,530 
 160 
 
 314,040 
 
 50,080 
 
 134,880 
 
 1,560 
 
 1,560 
 
 960 
 
 19,640 
 
 * This plant grows with equal luxuriance in soils containing only G80 pounds of carbonates. 
 
 In these tables the sequence of the different plants has been arranged 
 so that in each case the species having the highest optimum comes at 
 
— 46 — 
 
 the head of the list. Arranged in this way the tables show that where 
 these plants grow in luxuriance they may be considered indicative of 
 the following conditions : 
 
 Total Salts Indicators. — The Samphires, Alkali-heath, and Cressa are 
 all indicative of excessive total salts. Saltwort, Greasewood, and 
 Tussock-grass indicate much lower total salt-content; indeed, the 
 maximum of the two latter plants ( Greasewood and Tussock-grass) is 
 so low that the application of gypsum (land-plaster) would in some 
 cases (e. g. the Tussock-grass lands near Bakersfield) render the soil 
 adapted to the cultivation of Modiola and Australian Saltbush. 
 
 Salsoda Indicators. — It is noticeable that the relative position of the 
 different species in the columns of optimum and maximum is more 
 uniform in the salsoda table than in any other; and whether we 
 arrange the sequence of the plants according to the optimum or to 
 the maximum, the same relative position is maintained. This is in 
 complete accord with what our knowledge of the effect of salsoda on 
 vegetable life would lead us to expect; being by far the most injurious 
 of the alkali salts, the range of tolerance is much smaller, and the limits 
 are much more clearly defined than in the case of the other salts. 
 
 Luxuriant growths of Tussock-grass and Greasewood are invariably 
 indicative of high percentages of carbonates, but in such cases the total 
 salt percentage is sometimes so low that the application of gypsum (land- 
 plaster) would render the land fit for the cultivation of Modiola or even 
 Australian Saltbush, as noted above. It must be borne in mind, how- 
 ever, that where Tussock-grass grows but sparsely, the total salt-content 
 may reach 499,000 pounds, an amount rendering the land utterly worth- 
 less for agricultural purposes unless the surplus salts can be removed. 
 
 Alkali-heath cannot be taken as an accurate gauge of the salsoda 
 content, as it grows with equal luxuriance on soils containing respect- 
 ively 680 and 19,590 pounds to the acre, of this salt. 
 
 The Samphires and Saltworts are relatively low down in the carbonate 
 table, and may be taken to indicate a comparatively low percentage of 
 " black alkali." 
 
 Neutral-Salt Indicators. — The Samphires and Saltworts head the 
 neutral-salt tables, and are reliable indicators of excessively high per- 
 centages both of glauber salt and of common salt. Saltwort comes 
 next to Samphire in the common-salt table, but is not quite such a 
 good guide to the glauber salt. 
 
 Luxuriant growths of Alkali-heath, Greasewood, and Tussock-grass 
 indicate low percentages of the neutral salts, but these plants will some- 
 times tolerate (in a sparse state of growth) very high percentages. 
 
 o