SOIIv DEFICIENCIES 



The Bureau of Soils 1 of the United States Department of 

 Agriculture divides soils into six grades, according to their 

 average content of soluble salts to a depth of six feet. 



The quantities of alkali mentioned above refer to the total 

 quantity of soluble salts. 



Utilization of Alkali Soils. 2 (i) Growth of Resistant Crops. 

 One method of utilizing alkali soils is to grow crops which will 

 resist the action of the alkali present. One of the most resistant 

 crops is salt bush, which endures drouth as well as alkali, and is 

 used for pasturage, or as a hay crop. Sorghum, oats, and sugar 

 beets have a high resistance for alkali, also some varieties of 

 barley, but it is difficult to secure a stand of these crops when 

 more than 0.6 per cent, of the total salts is present. 



(2) Treatment of Black Alkali. Black alkali, due to sodium 

 carbonate, may be converted into sodium sulphate by means of 

 gypsum. The sulphate is much less harmful to plants and the 



1 Dorsey, Bulletin 35, p. 24. 



2 Hilgard, Bulletin 128, California Exp. Sta. 



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