IRRIGATION AND DRY-FARMING 689 



ice, established by Federal law June 17, 1902, providing 

 for the construction of irrigation works with the re- 

 ceipts from the sale of public lands in the arid and semi- 

 arid states. 



These several provisions and their successive growth 

 in size suggest the necessity of large enterprises and care- 

 ful coordination in providing water for irrigation. The 

 many attractive features of farming in arid regions under 

 irrigation, together with the publicity that the enterprises 

 have had, have has+ened the growth of irrigation farming 

 so that it now plays a very substantial part in the agri- 

 cultural business of the country. 



591. Irrigation in humid regions. — In the humid 

 states — that is, those in which there is a large normal 

 rainfall and in which crops can usually be produced with- 

 out artificial addition of water — irrigation has been 

 practiced to some extent. Irrigation is useful (1) where 

 the crop has a high value, as for vegetables and small 

 fruits near large cities ; (2) where the quality of the crop 

 is much affected by unfavorable conditions, as the pro- 

 duction of wrapper tobacco in northern Florida and of 

 rice in Louisiana ; (3) where the soil is especially sandy ; 

 and (4) where the supply of water may be very cheaply 

 applied to the land, as in the diversion of streams to adja- 

 cent fields, usually meadows. In Great Britain and^ in 

 central and southern Europe, the diversions of streams 

 to near-by grass meadows is relatively common. Under 

 all these conditions, small irrigation enterprises have 

 been developed in different parts of the eastern United 

 States. The rainfall under which irrigation is practiced 

 in these regions ranges from 30 to more than 60 inches 

 annually. The practice of irrigation in humid regions 

 is in the nature of an insurance against dry years. The 

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