20 DRY-FARMING 



fall, which up to the present seems to be the lower 

 limit of successful dry-farming, there is a maximum 

 possibility of producing 25 bushels of wheat annually. 

 In the subjoined table, constructed on the basis 

 of the discussion of this chaj^ter, the wheat-produc- 

 ing powers of various degrees of annual precipita- 

 tion are shown : — 



One acre inch of water will produce 2w bushels of wheat. 

 Ten acre inches of water will produce 25 bushels of wheat. 

 Fifteen acre inches of water will produce 37A- bushels of 



wheat. 

 Twenty acre inches of water ^\^ll produce 50 bushels of 



wheat. 



It must be distinctly remembered, however, that 

 under no known system of tillage can all the water 

 that falls upon a soil be brought into the soil and 

 stored there for plant use. Neither is it possible to 

 treat a soil so that all the stored soil-moistiu'e may 

 be used for plant production. Some moisture, of 

 necessity, .will evaporate directly from the soil, and 

 some may be lost in man}^ other ways. Yet, even 

 under a rainfall of 12 inches, if only one half of the 

 water can be conserved, which experiments have 

 shown to be very feasible, there is a possibility of 

 producing 30 busliels of wheat per acre eveiy other 

 year, which insures an excellent interest on the 

 money and labor invested in the production of the 

 crop. 



