CHAPTER XIII 



IRRIGATION 



IRRIGATION may be of two kinds, irri- 

 gation to supplement normal precipitation 

 in humid regions; or irrigation to provide 

 moisture for crop production in arid regions. 



Irrigation when used as a supplement to nor- 

 mal precipitation is considered as a form of 

 crop insurance, and is employed only with crops 

 producing a large net return per acre. This 

 method of using water and its economic effects 

 are discussed in connection with the subject of 

 crop insurance as well as under the special crops 

 requiring irrigation in humid sections.* 



No single factor in agricultural practice 

 offers greater advantages than a controllable 

 water supply. Water under control can be 

 applied as the soil and the plant require it and 

 in such quantity as the species demands. The 

 advantages of such a controlled water supply 

 need no demonstration or argument. 



* See also " Garden Farming." 

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