ON DRY-FARMING INVESTIGATIONS IN THE UNITED STATES. 281] 
often lighted at night in every direction by the flames of the burning 
stacks. Even where the straw alone has been removed, grain-farming 
in the Great Plains has resulted in a marked decrease in the nitrogen 
and humus of the soil. Alway*! has shown that the cultivation of 
the loess soils of Nebraska has been accompanied by a marked re- 
duction in nitrates, total organic matter, and humus. He attributes 
AVAILABLE SPRING AND Harvest Morsturr CONTENT. AKRON, COLORADO. 
Dateof 1908 1909 1909 1910 1910 191) (91 1911 1912 1912 1912 1913 1913 
Sompling g.27 4-7 8-25 3-17 710 4-8 6§-15 10-30 4-9 8-7 10-29 45 724 
2 
3 
“SS 
a4 
5 
6 
Fie. 7.—Growth-water at seed-time and harvest in spring-ploughed (A) and fall- 
ploughed (B) plats continuously cropped to grain. 
PLAT A 
a ww & ~@ mm f= 
the greatest loss of these components to the washing or blowing away 
of the surface soil. : 
Snyder *? found that the loss of nitrogen from four Minnesota 
grain-farms in ten years was from four to six times that removed 
by the crops. This loss he attributes to the rapid breaking-up of the 
*! Bulletin 111, Nebraska Experiment Station, 1909. 
* Bulletin 94, Minnesota Experiment Station, 1906. 
