[shutt] 



ALKALI IN CLAY SOILS 



229 



Plot I. — Water-soluble Saline Content Expressed in Percentages on Air- 

 Dried Soil. 

 Crops.— 1916, Wheat: 1917 and 1918, Western Rye Grass, Timothy and Brome: 

 1919, White Clover: 1920, Mixed Grasses and Clover: 1921, Mixed Grasses 

 and Clover. 



TABLE I. 



With respect to the zones "C" and "D", the results from year 

 to year are rather erratic showing remarkable fluctuations. It is 

 doubtful whether these movements can be attributed wholly or in 

 part to irrigation, for field notes made on examinations following 

 an irrigation indicate that the water had not penetrated below 1'.5. 

 A rise or fall of the water-table would, of course, be accompanied by 

 a corresponding change in the position of the alkali, but over this 

 area the water-table lies at a very great depth. The probable explan- 

 ation is that the alkali at depths lower than 1' 6" has not been 



