118 FARM MECHANICS 



ture as the air, and settles so gently that the most 

 delicate plants are not injured. 



Quantity of Water to Use. Good judgment is neces- 

 sary in applying water to crops in regard to quantity, 

 as well as the time of making application. Generally 

 speaking, it is better to wait until the crop really needs 

 moisture. "When the pump is started give the crop 

 plenty with the expectation that one irrigation will be 

 sufficient. Much depends upon the amount of moist- 

 ure in the soil ; also the kind of crop and weather con- 

 ditions enter into the problem. On sandy land that is 

 very dry where drainage is good, water may be per- 

 mitted to run in the corrugations for several days un- 

 til the ground is thoroughly soaked. When potatoes 

 are forming, or clover is putting down its big root sys- 

 tem, a great deal of water is needed. Irrigation suffi- 

 cient to make two inches of rainfall may be used to 

 advantage for such crops under ordinary farming con- 

 ditions. It is necessary after each irrigation to break 

 the soil crust by cultivation to prevent evaporation. 

 This is just as important after irrigation as it is after 

 a rain shower. Also any little pockets that hold water 

 must be carefully drained out, otherwise the crop will 

 be injured by standing water. We are not supposed 

 to have such pockets on land that has been prepared 

 for irrigation. 



Kind of Crops to Irrigate. Wheat, oats, barley, etc., 

 may be helped with one irrigation from imminent fail- 

 ure to a wealth of production. But these rainfall 

 grain crops do not come under the general classifica- 

 tion that interests the regular irrigation farmer beyond 

 his diversity plans for producing considerable variety. 

 Fruits, roots, clover, alfalfa, vegetables and Indian 

 corn are money crops under irrigation. Certain seed 



