258 IRRIGATION PRACTICE 



be well stored with moisture at the time of seeding, and 

 when this is not the case it may be necessary, as in the 

 case of wheat, to give the soil a thorough soaking before 

 planting. 



162. Time to irrigate corn. Corn is planted later 

 than the small grains and during its early growth is, 

 therefore, subjected to a higher temperature and more 

 rapid evaporation. However, the young plant draws little 

 water from the soil, and the first irrigation after seeding 

 should be light and should come as late as possible. As 

 the plant continues its growth the irrigations may be 

 increased in quantity and frequency. The May planting 

 of corn means that July and the first half of August are 

 the periods of most rapid growth and during which most 

 irrigation is needed. After August 15, less water is 

 required; in fact, it is questionable if water should be 

 applied to corn after the period of August 15 to September 

 1. As in the case of the small grains, the key to the suc- 

 cessful production of irrigated corn seems to be to keep 

 the soil in a uniform moisture condition throughout the 

 season. It is manifestly impossible under irrigated con- 

 ditions to keep the soil exactly at the same percentage of 

 moisture; but, by proper cultivation and irrigations at 

 correct intervals, the soil may be maintained throughout 

 the season at a favorable moisture percentage. Excessively 

 dry and wet periods should never follow each other. 



Corn, like the small grains, should have at its disposal 

 an abundance of water at the time of seed-formation. When 

 the seed is ripening, little water is required; in fact, in 

 the later periods of growth, water must be withheld from 

 the plant, so that ripening may not be delayed. If little 

 water is available during -the season, two irrigations are 

 probably sufficient, and two are better than one. In one 



