CEREALS UNDER IRRIGATION 425 



booting and soft-dough stages in one case, and at the 

 jointing and flowering stages in another. The grain 

 which received no water ripened 5 days earlier than that 

 which received the most. In these experiments the water 

 was applied by flooding between borders. 



455. Winter irrigation. The utility of irrigation dur- 

 ing the winter or non-growing season appears to have 

 been demonstrated in some localities where the water 

 supply is sufficient. In such cases, water applied in the 

 winter or early spring serves to store moisture in the soil 

 for later use of the crop, when the water supply is con- 

 stantly needed for other crops. In winter the land is 

 irrigated once or twice before freezing weather, the first 

 irrigation being 2 weeks or a month prior to the second 

 one, which should be given just before heavy frost occurs. 

 Winter irrigation is best done by the furrow method ; 

 or the land should be harrowed after the second irrigation, 

 as a mulch surface is desirable to hold the winter precipi- 

 tation. The soil should be saturated to a depth of 4 to 

 6 feet (McLaughlin, 1910, p. 15). 



456. Fall irrigation where winter rains are lacking 

 has been found very desirable. The localities where it is 

 particularly advantageous are likely to be near the eastern 

 border of the Western area, where there is little winter 

 precipitation, as in the Great Plains. Knorr (1914) has 

 experimented 3 years with fall irrigation on wheat, oats, 

 and barley, at the Scottsbluff, Nebraska, substation. 

 The resulting yields were 5.5 more bushels an acre of 

 wheat, 7 more bushels of barley, and 11 more bushels of 

 oats, after fall irrigation, than on land not so treated, but 

 irrigated afterward as usual. The crops fall-irrigated 

 also grew from 1 to near 2 inches taller, and produced 

 more straw to the acre, but less straw to a bushel of 



