SUGAR BEETS, POTATOES, ETC. 301 



connecting yield with irrigation is the same for potatoes 

 as for other crops. However, the yield of potatoes is 

 more nearly proportional to the water used than are 

 sugar beets or the other root crops. This may be due to 

 the fact that the potato is an enlarged stem. Following 

 the Utah results, when 30 acre-inches were applied to 1 

 acre, 195 bushels of potatoes were obtained; when spread 

 over 6 acres, 691 bushels were obtained. (Fig. 84.) 



The quality of potatoes is also definitely affected by 

 the quantity of water used. Medium quantities produce 

 starchy potatoes; if too little or too much water is used, 

 the percentage of starch is materially lowered. 



It is probable that the duty of water for potatoes 

 should not be greatly different from that for sugar beets. 

 From 15 to 24 inches should represent an ample quantity 

 of water for the production of a good crop of potatoes, 

 wherever the annual rainfall is hi the neighborhood of 15 

 inches, and where the soils are deep and well cultivated. 

 It has been found possible in the arid regions to raise 

 large crops of first-class potatoes without irrigation, and it 

 is probable that the duty of water for potatoes will be 

 greatly increased as fuller knowledge is obtained. 



181. Peas and beans. Peas and beans are becoming 

 important irrigated crops. They are especially valuable 

 because, like lucern, they grow well on raw soils that 

 are unwilling to yield the ordinary crops when first brought 

 under cultivation. Of late years these crops have become 

 valuable hi the hog and sheep industry. The sheep eat 

 the vines and the hogs the seeds. Large quantities of the 

 proper varieties of peas are also canned, and in that con- 

 dition shipped all over the earth. 



Peas and beans may be grown either as garden or 

 field crops. They are characterized by a rather short 



