CHAPTER XXX 



IRRIGATION AND DRY-FARMING 



Irrigation ^ is the application of water to the soil for 

 the purpose of growing crops. It is supplementary to the 

 natural precipitation. The quantity of water applied 

 and the time of application must therefore be determined 

 by the character of the rainfall. 



587. Relation of irrigation to rainfall. — The limit of 

 rainfall where irrigation becomes necessary is not a fixed 



1 Widtsoe, J. A. Principles of Irrigation Practice. New 

 York. 1914. 



Olin, W. H. American Irrigation Farming. CMeago. 1913. 



Bowie, A. Practical Irrigation. New York, 1908. 



King, F. H. Irrigation and Drainage. New York. 1899. 



Paddock, W., and Whipple, 0. B. Fruit Growing in Arid 

 Regions. New York. 1910- 



Newell, P. H. Irrigation. New York. 1902. 



Mead, E. Irrigation Institutions. New York. 1903. 



Mead, E. Preparing Land for Irrigation and Methods of 

 Applying Water. U. S. D. A , Office Exp. Sta., Bui. No. 145. 

 1904. 



Wiekson, J. A. Irrigation among Fruit Growers on the 

 Pacific Coast. U. S. D. A., Office Exp. Sta., Bui. No. 108. 

 1902. 



Widtsoe, J. A., and Merrill, L. A. Methods for Increasing 

 the Crop Producing Power of Irrigation Water. Utah Agr. 

 Exp. Sta., Bnl. No. 116. 1912. 



Fortier, S. The Use of Small Water Supplies for Irrigation. 

 U. S. D. A., Yearbook, p. 409. 1907. 



Fortier, S. Irrigation of Orchards, U. S. D. A., Farmers' 

 Bui. 404. 1910. 



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