METHOD OF IRRIGATION 



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"laying off" the land. (Fig. 52.) The furrows are made at 

 right angles to the supply ditch, or, if the land is irregular 

 in contour, they are made to follow the contour lines. 

 This is done, especially, in orchards where trees grow 



FIG. 50. Furrow irrigation of young alfalfa. 



on the hillsides. It is not an uncommon sight in such 

 districts to see thirty or forty furrows filled with water 

 zigzagging down a hillside. 



The furrows are made from year to year, except in the 

 case of alfalfa and other perennial crops. Alfalfa, when 

 irrigated by this method, is furrowed the first year, and 

 the permanent furrows are only deepened or cleaned out 

 from year to year. The disadvantage of the permanent 

 furrows is that as the mower travels across them the rider 

 is shaken up considerably and the machine is injured. In 

 wheat fields, furrows are laid off soon after the wheat is 

 planted, when it is about 3 or 4 inches high. Fields of 

 sugar beets, potatoes and similar crops are furrowed just 

 before the first irrigation. One furrow is ordinarily made 

 between every two rows of plants, although on some soils 



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