832 EXPERIMENT STATION RECORD. 



tion of soil conditions (alkali content and mechanical analysis), nsually to a depth 

 of G ft., occasionally to a greater depth, over 6 townships in that part of what is 

 known as the Colorado Desert, which is now ])eintj irrigated by means of a canal 

 from the Colorado Eiver. The Colorado Desert "is undoubtedly the site of an old 

 inland sea which has long since dried up, leaving a basin, at the bottom of which is 

 the Salton Sink, at a depth of 280 ft. below the present sea level, with a surface 

 heavily incrusted with salts which are mined for domestic purjioses. The rim of 

 this basin is composed of soils which have been considerably modified by the occa- 

 sional overflow of the Colorado River, which runs into this area for a short time 

 every few years." 



Five types of soil are described and mapped — namely, dune sand, which covers 

 27.7 per cent of the area; sand, 1 per cent; sandy loam, 21.9 per cent; loam, 28 per 

 cent; clay, 21.4 per cent. All of these types are " in places excessively alkaline, and 

 even where the surface 6 ft. shows no accumulation, the soil is underlaid by an 

 alkali-bearing clay subsoil." The composition of this alkali is reported to be as fol- 

 lows: Calcium sulphate, 9.91 per cent; magnesium sulphate, 9.02 per cent; sodium 

 sulphate, 0.33 per cent; potassium chlorid, 30.02 per cent; sodium bicarbonate, 9.59 

 per cent; sodium nitrate, 8.91 per cent, aiad sodium chlorid 32.22 per cent. The 

 determinations of the alkali at 1 ft. intervals to a depth of 6 ft. in the different bor- 

 ings are rejiorted in detail and the distribution of the alkali in the soil is mapped. 



The results of the survey show "that of the 169 square miles surveyed about 51 

 per cent is either too rough for economical irrigation or contains too high a salt 

 content for any but the most alkali-resistant plants to withstand. The remaining 

 49 per cent of the area it is believed can be safely cultivated, provided suitable pre- 

 cautions are taken in the use of a proper amount of irrigation water, in the adoption 

 of careful methods of cultivation, and, where necessary, in the installation of under- 

 drainage to carry off the excess of seepage waters and alkali. . . . 



"The claims for the fertility of this country are based upon the experience gained 

 from irrigation along the Colorado River below Yuma. An examination of the 

 country reveals the fact that the conditions below Yuma are very different from 

 those in the Imperial area, and the agriculture of the two areas is not comparable. 

 The soils of the bottom lands below Yuma are lighter in texture, more pervious to 

 water, contain less alkali, and are, many of them, well adapted to alfalfa." 



Alkali lakes and deposits, W. C. Knight and E. E. Slosson ( Wnoming Sta. Bui. 

 49, j)p. 71-123, firj. 1, map 1). — This bulletin gives a general discussion of the occur- 

 rence of alkali deposits in Wyoming, and a special treatise on their chemistry, geology, 

 mineralogy, and origin. As regards the origin of the alkali salts, the conclusion has 

 been reached that "primarily the alkali has been produced by the decomposition of 

 the various rocks containing these elements. These salts appear to have been formed 

 extensively during the INIesozoic and Cenozoic eras, but in place of being stored in 

 deposits were carried down with the sediments. Later through the mountain-making 

 agencies these formations were brought to the surface, and through the influence of 

 decomposition and erosion have been converted into soil. The salts have remained 

 in the soils so formed, since there has not been sufficient water to leach them out. 

 The decomposition of the rocks is still in progress, and from this source and the stor- 

 age already accumulated in the soils the deposits of alkali have been formed and are 

 being increased." 



Eight groups of deposits in the State are described in detail, viz, "Downey, Union 

 Pacific, Rock Creek, Rankin, Bothwell, Morgan, Independence, and Gill. These are 

 all located in the southeastern part of Wyoming, and are confined to Albany, Carbon, 

 and Natrona counties." The chemical composition of only those deposits in which 

 the alkali is of considerable depth and purity, i. e., the so-called "soda lakes," la 

 considered in this bulletin. "The salts found in the soda lakes are the same as those 

 which occur in the soil of the surrounding region and form alkali crusts as they are 



