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 
Fic. 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, commonly 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 ordinarily found 
