ALFALFA, FORAGE CROPS AND PASTURES 277 



will take more water and give good returns. The abun- 

 dance of water must always be considered in determining 

 the water to be used on alfalfa fields, for it will determine 

 whether the acre yield or the acre-inch yield is of first 

 importance. Fortier's results show that 30 acre-inches, 

 used on one acre, produce about 14,400 pounds of alfalfa 

 hay; on five acres, about 64,100 pounds. It is probably 

 safe to say that, on the fertile soils of the West, not more 

 than 18 niches of water need be applied to alfalfa, provid- 

 ing the crop is given good cultivation. On soils that are 

 infertile, shallow, very sandy or underlaid by hardpan, 

 more can probably be well used. This depth of water 

 refers to districts which receive an annual rainfall of 12 to 

 15 inches. Where less rain falls, more water must probably 

 be added in irrigation; where more, less need be applied. 



The irrigation season for alfalfa covers approximately 

 120 days June to September, inclusive. During this 

 period one second-foot will cover 240 acres to a depth of 

 12 inches; 150 acres to a depth of 18 inches; 120 acres 

 to a depth of 24 inches. The best managed irrigation 

 systems have a duty of water for alfalfa of about 150 

 acres, which is increasing. 



Irrigated alfalfa hay is of high quality. The quantity 

 of water used in producing alfalfa determines, in a large 

 measure, the quality of the hay. The more water used, the 

 more woody the hay becomes, and the less valuable, 

 therefore, for feeding purposes. The less water used, the 

 richer the hay becomes, per pound, in the blood- and 

 muscle-forming elements. All in all, as with other crops 

 so with alfalfa it must be grown with a moderate quan- 

 tity of water. 



170. Alfalfa seed. The present large demand for al- 

 falfa seed is likely to continue as long as new lands are being 



