USE OF WATER BY SPRING WHEAT ON 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 acre 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 1909 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 



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Pig. 4. — Diagram showing the use of water by 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 years 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 



