284 



SCIENCE. 



[Vol IX., No. 215 



of soil is exposed to this leaching action, and 

 more alkali put in circulation, particularly if these 

 lower strata are rich in alkali or materials yield- 

 ing it. 



If, on the other hand, the water is used lavishly 

 but without proper provisions for drainage, evil 

 effects are produced in a somewhat different way. 

 In this case the level of the hydrostatic water of 

 the soil (its water-table) is brought nearer the 

 surface. The water has a less distance to rise by 

 capillary action, hence rises more abundantly and 

 for a longer time, and an accumulation of alkali is 

 brought about. In one or other of these ways is 

 brought about the phenomenon well des^jribed in 

 local nomenclature as the 'rise of the alkali,' — a 

 thing which is threatening most serious injury to 

 the irrigated lands of the San Joaquin valley. 



All these and other points are brought out most 

 plainly in detail in the report before us. One in- 

 teresting point deserves special mention. Analy- 

 sis shows that the alkali of these soils is in many 

 cases rich in plant-food, often containing phos- 

 phates and potash salts in practically inexhausti- 

 ble quantities, and not infrequently considerable 

 amounts of nitrates ; and that, if its excessive 

 accumulation can be prevented, the soils contain- 

 ing it viill prove extremely fertile. 



The question of remedies is fully considered. 

 "When irrigation is practised, the prime condi- 

 tion of success is a thorough system of drainage, 

 combined with an occasional flooding with a large 

 quantity of water, in order to wash out the soluble 

 alkali into the drainage in case the rains of the 

 rainy season do not accomplish this sufficiently. 

 Drainage may, further, so lower the water-table 

 as to greatly diminish the amount of water rising 

 througli the soil, while the roots of plants can 

 readily penetrate to considerable deptlis for a sup- 

 ply of water. The author is very emphatic in his 

 statements that irrigation without provision for 

 drainage is suicidal. 



Second in importance to drainage, is thorough 

 cultivation of the surface in order to diminish 

 evaporation. Mulching has a similar effect. 

 This necessitates, however, the cultivation of 

 crops admitting of tillage. Hitherto wheat has 

 been the staple crop of the region under discus- 

 sion, regarding which Professor Hilgard remarks 

 that " it would really seem as if, in the broadcast 

 culture of cereals, the farmers in the alkali districts 

 had made the worst possible selection for the per- 

 manent good of agriculture in their region." As 

 crops suited for alkali soils, he suggests alfalfa (a 

 deep-rooting crop, which shades the ground and 

 thus diminishes very largely surface-evaporation) 

 for a forage-crop, and also roots, where these can 

 be utilized for feeding purposes. As crops for 



sale, he suggests, first, cotton ; then the castor- 

 bean ; further, fruits, especially raisins and 

 prunes ; and possibly sugar-cane and sorghum. 



As supplementary to drainage and tillage, cer- 

 tain chemical antidotes may he employed. Land 

 containing carbonate of soda is greatly benefited 

 by gypsum ; a double decomposition yielding, in 

 the presence of water, carbonate of lime and sul- 

 phate of soda, both relatively innocuous as com- 

 pared with carbonate of soda. Soluble earthy 

 and metallic sulphates and chlorides niay be pre- 

 cipitated by lime, or sometimes by calcareous 

 marl even. 



It is evident, however, that these chemical an- 

 tidotes only change the nature of the alkali, but 

 do not remove it from the soil. Indeed, they 

 tend rather to add to the amount of easily soluble 

 matters in the soil, and, when the amount of 

 alkali is at all large, are to be looked upon simply 

 as adjuncts to the measures before mentioned. 



Thus far the irrigation-water itself has been 

 tacitly assumed to be pure. In fact, however, 

 this is by no means the case ; and a most impor- 

 tant part of Professor Hilgard's work upon this 

 matter has been his examinations of the water 

 available for irrigation. The water of Tulare 

 Lake, for example, — one of the large bodies of 

 water that had been counted on for purposes of 

 irrigation, — was found to contain so much alkali, 

 especially carbonate of soda, as to render it unfit 

 for irrigation. Kern Lake and Buena Vista Lake 

 were found to be even more alkaline than Tulare 

 Lake. These waters, when concentrated in the soil 

 by evaporation, must rapidly increase its content 

 of alkali, and prove fatal to all cultivated crops. 

 Even the purer w-aters of the rivers were found 

 to contain more or less alkali ; and in regard to 

 them all, the necessity of combining drainage 

 with irrigation is to be emphasized. 



A most interesting and instructive appendix to 

 Professor Hilgard's report is constituted by the 

 report of the ' reh committee' for the Aligarh dis- 

 trict, northern India, reh being the Hindoostanee 

 equivalent of 'alkali.' From this it appears, that, 

 in the irrigated districts of northern India, the 

 same phenomena have been observed as are now 

 developing themselves in California ; and the 

 government is now confronted with the necessity 

 of carrying out difficult and costly remedies, or 

 apparently of abandoning altogether or in large 

 part its system of irrigation. In regard to the 

 question of remedies, the Indian committee is 

 substantially at one with Professor Hilgard, mak- 

 ing due allowance for the fact that in India the 

 question is one of remedying an existing evil, 

 while in California it is as yet largely one of 

 prevention. 



