274 



IRRIGATION PRACTICE 



It may be observed that 1.28 per cent of the total 

 quantity applied during the seaon, was added in April. 

 That undoubtedly was due to the lack of water in the soil 

 at that time. The May irrigation, likewise, was doubt- 

 lessly applied to lands not well saturated with moisture 

 in the spring. The bulk of the irrigation came in July 

 and August, during the time of the second and third 

 cuttings. 



169. Quantity of water for alfalfa. The growing sea- 

 son for alfalfa is longer than for the small grains, but to 

 offset this it uses less water for each pound of dry matter. 

 Nevertheless, the heavier acre-yield of alfalfa makes 

 necessary more irrigation for alfalfa than for the cereals. 

 The law connecting yield of alfalfa with the quantity of 

 water used is the same as that developed for other crops. 

 In the following table are given the results of experiments 

 on the water requirements of alfalfa conducted by Fortier 

 in Montana: 



YIELDS OF CURED ALFALFA HAY WITH VARYING QUANTITIES OF 

 IRRIGATION WATER 



The depth of irrigation water varied from 6 to 36 

 inches; the total yield of well-cured alfalfa hay, from 

 9,000 to 15,000 pounds. As shown in the third column of 

 the table, the yield did not keep pace with the increase 



