30 



BULLETIN 339, U. S. DEPARTMENT OP AGRICULTURE. 



deficient or excessive water application have been eliminated, as have 

 a few tracts on which a very large increase in water application was 

 necessary to produce a small increase in the yield. The remaining 

 data, some 50 per cent of the original data secured, have been grouped 

 in Tables XIV and XV. 



Table XIV. — Average depths of water applied to 119 selected fields of grain and potatoes 

 on medium clay and sandy loam soils, by months. 



[Altitudes ranging from 2,400 to 5,000 feet.; 











Number 

 of plots. 



Depth of water applied. 



Season. 



Apr. 

 16-30. 



May. 



June. 



July. 



August. 



Total for 

 season . 



1910 



31 

 30 

 25 

 33 



Foot. 



Foot. 

 0.32 

 .03 



Foot.. 



0.60 



.65 



.94 

 .54 



Foot. 

 0.55 



.48 

 .66 

 .59 



Foot. 



0.08 



.01 



.05 



.23 



Feet. 

 1.55 



1911 





1.17 



1912 





1.65 



1913 



0.04 



.21 



1.61 









.01 

 .67 



.14 

 9.28 



.68 

 45.91 



.57 

 38.10 



.09 1 - 50 







6.06 



, 









Table XIV shows that both the months and the seasons have 

 varied somewhat in their requirements and that the average annual 

 requirement of water for this class of crop was 1.50 feet per acre. 

 The results shown by the table are based upon the same data as 

 are included in figures 5, 7, and 8, but were arrived at in a different 

 manner. There is a very close agreement in that the requirement 

 of water shown by the table is practically the same amount as that 

 which the curves indicate will produce the maximum yield on both 

 fertile and infertile soils. 



Table XV shows the average depths of water used on alfalfa, 

 arrived at in the same way. 



Table XV. — Average depths of water applied to 52 selected fields of alfalfa and clover on 

 medium clay and sandy loam soils. 



[Altitudes ranging from 2,400 to 5,000 feet.] 







Depth of water applied. 



Season. 



Number 

 of plots. 



April — 



May. 



June. 



July. 



August. 



Sep- 

 tem- 

 ber. 



Total 



for 

 season. 







1-15. 



16-30. 



1910 



1911 



1912 



15 

 13 

 11 



Foot. 

 0.06 



Foot. 



0.02 



.04 



Foot. 



0.55 



.49 



.49 



.86 



Foot. 



0.74 



.29 



.50 



.23 



Foot. 



0.65 



.91 



.62 



.74 



Foot. 

 0.61 



. .70 

 .61 

 .39 



Foot. 



0.07 



.25 



.04 



.02 



Feet. 

 2.70 

 2.68 

 2.26 



1913 13 







2.24 













.02 



.8 



.02 



.8 



.60 



24.1 



.44 

 17.7 



.73 

 29.3 



.58 

 23.3 



.10 

 4.0 



2.49 











