METHODS OF IRRIGATING 



41 



very close together, as is common with onions and similar crops, 

 one furrow for every two or three rows may be sufficient. In 

 crops planted far apart, like melons, one furrow is usually made 

 for each row but is close to the row rather than midway between 

 two rows (Fig. 20). 



After the furrows are made and little ditches cut to connect 

 them with the lateral, the water is turned from the lateral, by 

 means of a temporary dam, into a few^ of the furrows at a time. 

 It is allowed to run the entire length of these furrows and continue 



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^^' 



;-^,, 





^•S'^i^ 



Fig. 22. — Conserving moisture by thorough tillage. 



running until the soil surrounding the plants becomes well soaked 

 with water. The temporary dam in the lateral is then moved 

 downstream a few feet, and dirt is quickly shoveled in to close 

 the little ditches leading from the lateral to the furrows already 

 irrigated. The process is repeated, irrigating a few rows at a time, 

 until the whole field has been watered. The number of rows that 

 can be irrigated at a time is determined mainly by the head of 

 water available. For irrigating celery, the furrows are connected 

 with the lateral by means of miniature water gates, which make 

 it possible to regulate to a nicety the amount of water delivered 

 into each furrow, and thus avoid flooding. 



