FERTILITY OF DRY-FARM LANDS 



285 



ing virgin lands. The determinations were made 

 to a depth of eighteen inches. Alway and Trumbull, 

 on the other hand, found in a soil from Indian Head, 

 Saskatchewan, that in twenty-five years of cultiva- 

 tion the total amount of nitrogen had been reduced 



Fig. 68. Dry-farm white hull-less barley. Choteau, Montana, 1909. 

 Yield, 48 bushels per acre. 



about one third, though the alternation of fallow 

 and crop, commonl}^ practiced in dry-farming, did 

 not show a greater loss of soil nitrogen than other 

 methods of cultivation. It must be kept in mind 

 that the soil of Indian Head contains from two to 

 three times as much nitrogen as is orchnarily found 



