CEREALS UNDER IRRIGATION 



433 



In general, a proportional increase in the vegetative 

 growth of the plants, compared with grain production, 

 occurs as the water supply is increased. Also the period 

 of growth is prolonged and maturity delayed by irrigation. 

 A day or less after irrigation, the color of the leaves of 

 barley turns to a somewhat deeper shade. Irrigation not 

 only softens the kernels of hard wheats as already men- 

 tioned, but also weakens the straw of all small cereals, 



FIG. 139. Irrigation canal on the Huntley Project, Huntley, Montana. 



and increases the tendency to lodge. Early cessation of 

 irrigation will reduce the bad results of this tendency. 

 Frequent applications of water will create conditions 

 favorable to the spread of rust. Naturally cereal crops 

 intended for forage require more irrigation than those 

 grown for the grain. Figure 139 shows an irrigation 

 development in the grain country of the Great West. 



470. Cereals as cover-crops are of more consequence 

 under irrigation than in dry-farming, except in so far 

 as they are considered as green-manures. 

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