16 
BULLETIN 1004, U. S. DEPARTMENT OF AGEICULTURE. 
two days of the harvest date. The years 1911 and 1913 were unfa- 
vorable for wheat. In both these years there was enough water in 
the fallow plat to start the wheat growing rapidly, but in both years 
the crop soon commenced to suffer from drought, and the resulting 
lower rate of water use and low yield are shown. Harvest in both 
of these years was earlier than in the favorable years. 
A con^parison of the two figures shows one striking fact. The 
wheat on plat A m 1912 used more water than the wheat on plat A 
in 1909 and made a considerably higher yield. On plat C or D 
the quantity of water used in 1909 was greater than in 1912, and 
the yield was higher. For the quantity used, the crop on both plats 
in 1909 shows a lower yield than in 1912. This is probably explained 
by the later seeding. 
A comparison of Figures 4 and 5 shows how ineffective in the 
growth of spring wheat fallowing has been as a means of combating 
drought at this station. In 1909, 1911, and 1913 there was only a 
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-Diagram showing the use of water ou wheat plat C or D at Akron, Colo, 
the yeai's 1909, 1911, 1912, and 1913. 
for 
little more water in the fallow plat C or D than in the continuously 
cropped plat A, and only a slightly higher yield was secured. In 
1912 the continuously cropped plat A had more water and made a 
higher yield than the fallow plat C or D. In no year has there been 
enough additional water stored in fallow above that in continuously 
cropped land to carry a crop over any prolonged period of drought. 
In general, the Akron curves represent a condition of water use 
from a soil of medium water-storage capacity. Comparison of the 
Akron curves with those of Dickinson shows the difference between 
the two. stations in the quantity of water furnished to a crop through 
fallowing and the resulting increase in yields on fallow over those 
on continuously cropped land. 
