54 



BULLETIN 1026, U. S. DEPAETMENT OF AGKICULTTJKE. 



next. If the land is rolling, the laterals are spaced to follow the 

 ridges and water is turned down both slopes. On very uneven land 

 it is customary to build the field laterals to high points where the 

 water is turned out to be directed here and there by temporary dikes 

 thrown up with a shovel. To get the water from the lateral to the 

 field cuts are made in the banks at intervals of from 5 to 20 feet and 

 the water is forced through by checking the lateral farther down 

 with a canvas, metal, or dirt dam. 





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MAY 

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JUNE 

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AUGUST 

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Fig. 



6. — In-igation of grain. Water requirements of 622 acres in 1916 and 

 of 429 acres in 1917. 



By far the greater part of the area irrigated by the furrow method 

 is in sugar beets and potatoes, but corn, beans, peas, and truck are also 

 irrigated in this manner. In the valley irrigation by this method 

 consists in plowing furrows between the rows and running water 

 down these furrows from notches cut in a ditch at the head of the 

 field. Furrows are made in each middle with a shovel or other suit- 

 able plow and are especially deep for potatoes. To secure an even, 

 fast irrigation, furrows are usually about 500 feet long, but the type 

 of soil, slope of land, and amount of water available will cause a wide 



