THE WATER-COST OF DRY MATTER 



153 



before the acre-inch yield, the criterion of irrigated regions. 

 The understanding of this principle must be brought 

 into the practices of the people, and must reshape the 

 irrigation laws of the states and federal government, if 

 the greatest prosperity shall be won for the West. In 

 the day to come, it is probable that no farmer, though he 

 own an abundance of water, will be allowed to use more 



32000 



24000 



8000 



Stigar&eels 



Fio. 29. Crop-producing power of 30 acre-inches (sugar beets) 



than the quantity determined upon by the state as being 

 the best. 



The evils of over-irrigation are many. In addition to 

 those mentioned, it is shown in this chapter that the large 

 acre-use of water may diminish the actual yield an acre, 

 and invariably does make the crop more expensive from 

 the point of view of the water used for each unit of dry 

 matter. The permanence of irrigation-farming depends 

 on the moderate use of water. (Figs. 27-29.) 



