SPECIAL FARM TOPICS 277 



The need of irrigation in any region, arid or humid, is deter- 

 mined, not by the total amount of rainfall occurring during the 

 year, but by its distribution throughout the year; in other words, by 

 the amount of rainfall occurring in the crop-growing season, May 

 to October, during which period the warmth and light of the sun's 

 rays are most effective. In the humid portion of the United States, 

 even in localities in Florida where they have from 60 to 70 inches 

 of annual rainfall, irrigation is used successfully as a means of in- 

 suring the crop against drought due to the uneven distribution of 

 the rainfall. 



In these regions, however, irrigation is not so necessary to 



Erofitable agriculture, as it is in the West, and the problem is not 

 ow to get the largest possible returns from a limited water supply, 

 but whether the supplying of water to plants during dry seasons or 

 during the short dry periods which occur in almost every season 

 will increase production enough to repay the expense incurred. 

 This, of course, includes a study of the most economical means of 

 securing a water supply and the best methods of applying it to crops. 

 Experiments made in Missouri, Wisconsin, and New Jersey have 

 demonstrated that irrigation in those sections is highly profitable. 

 The work in Missouri is mainly with small fruits and nursery stock. 

 The experiments in Wisconsin include field as well as garden crops, 

 and at present the irrigation of cranberries is being thoroughly 

 tested. In New Jersey small fruits and garden crops have been irr 

 rigated with success. 



Irrigation is most extensively practiced in the growing of fall, 

 winter, and spring truck crops along the Atlantic coast from Vir- 

 ginia to Florida. The prevailing methods of application are by 

 sprinkling and through underground pipes, both of which are very 

 expensive. If cheaper methods can be made to serve equally well, 

 the saving to the truck growers will be very great. 



The greatest field for irrigation in the humid district is, how- 

 ever, in the Southern 'States. Here extensive systems of irrigation 

 from wells or streams by pumping have been established. 



Irrigation is not merely a recourse to insure the safety of a 

 crop. It has been demonstrated beyond question both by practical 

 experience and by systematic experiment that growth and produc- 

 tion can be profitably pushed by irrigation even when the natural 

 moisture seems ample, and in this respect irrigation aligns itself with 

 fertilization and cultivation as a factor in intensive culture. 



Another error grows out of the large scale upon which irriga- 

 tion is generally known to be carried on, involving canals and 

 ditches too expensive for individual undertaking. The impression 

 is made that considerable capital and engineering skill are necessary 

 to success; 'but as a matter of fact profitable irrigation is easily atr 

 tainable by small effort. It lends itself readily to small individual 

 or co-operative undertaking, developing water whose presence may 

 be almost unsuspected, or utilizing water which ordinarily is either 

 wasted or is a positive detriment when not turned to profitable 



