USE OF WATER BY SPRING WHEAT OX GREAT PLAINS. 
15 
not reach the period of rapid growth as early as in other years. 
From the time it commenced rapid growth until harvest the crop 
did not suffer greatly for lack of water, and there was a resulting 
good yield. While the yield of 14.3 bushels per aci'e is not high, it 
is fair for the locality and as high as could be expected from wheat 
planted as late as April 23. In 1912 the crop commenced to use 
water rapidly earlier than in 190.9 and used it at practically the 
same rate. The determination on May 16 represents an extreme 
example of experimental error. In this case it is evident that the 
rate of water use shown from April 27 to May 16 is too high, and 
that from May 16 to June 4 too low. It is due to the fact that the 
soil samples taken on May 16 showed a lower percentage of moisture 
20 
/s 
/ 
/s 
/ 
/5 
/ /6 
Fig. 4. — Diagram showing the use of water bv the wheat crop on plat A at Akron, Colo., 
for the years 1909, 1911, 1912, and 1913. 
than later conditions indicate were warranted. The years 1911 and 
1913 both represent seasons when the wheat crop suffered for mois- 
ture from the time it began rapid growth until harvest. In both 
years there is a resulting low rate of water use and low yield shown. 
Likewise, there is an earlier harvest date than in the two years that 
were favorable for wheat. 
Figure 5 shows the water use on plat C or D at Akron. Colo., for 
the same j^ears shown in Figure 4 for plat A. The year 1909 was 
favorable for wheat, and the wheat did not suffer for water at any 
time during its growing season. That it did not yield more than 
18.5 bushels per acre was doubtless due to the late date of seeding. 
In 1912 the crop actually ran out of water before harvest, and the 
result is shown in the lower use of water and the slightly lower 
yield. From the figure it would appear that the date of harvest 
was later in 1912 than in 1909. The crop in 1912 actually was 
harvested on August 9, but no soil samples were taken on this plat 
until August 16. In all other cases soil samples were taken within 
