264 



PRINCIPLES OF AGRICULTURAL CHEMISTRY 



plant, the character of the soil, the composition of the alkali, the 

 distribution of the alkali, and other conditions which influence the 

 growth of the plants themselves. The most injurious salts are 

 the carbonates; the least injurious are the sulphates. 



The California Experiment Station 1 has endeavored to deter- 

 mine the tolerance of various plants for alkali by estimating the 

 amount of alkali in soils in which the respective plants did well 

 or ill. The depth of four feet was chosen, because the strata be- 

 low that depth contain little alkali, and because rainfall or irriga- 

 tion water ordinarily does not penetrate below that depth. The 

 total amount in this depth must be considered. 



The results of these California investigations are as follows. 

 These figures, as stated, are tentative and subject to change: 



HIGHEST AMOUNT OF ALKALI IN WHICH PLANTS WERE FOUND 



UNAFFECTED, IN POUNDS PER ACRE TO THE 



DEPTH OF FOUR FEET. 



L,oughridge, Bulletin 133. 



