26 



BULLETIN 339, U. S. DEPARTMENT OF AGRICULTURE. 



used. Where 2.8 feet per acre were applied each acre-foot gave a 

 return of 584 pounds of grain, while an application of but 0.4 foot per 

 acre yielded at the rate of 3,474 pounds per acre-foot, or very nearly 

 six times as much grain per unit of water as was secured where the 

 larger application was made. It must be noted, however, that the 

 yield per acre with the application of but 0.4 foot per acre was rather 



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Fig. 5.— Yield per acre and per acre-foot of water applied from 96 plots of spring wheat at Gooding 

 experiment station during five years, 1910 to 1914. 



low and would not be profitable in many cases, because the returns 

 would not equal the cost of production. While these two curves 

 indicate the results which will be obtained by applying different 

 volumes of water to spring wheat on this type of soil for the condi- 

 tions obtained in southern Idaho, the economic quantity to allot for 

 grain is a distinct problem. Whether, it is more profitable to use 

 little water per acre and get a large return per acre-foot of water and 

 a low yield from the land, or to use more water and get a large return 



