CHAPTER XVI 



IRRIGATION AND DRY-FARMING 



iRRiGATiON-farming and dry-farming are both 

 systems of agriculture devised for the reclamation of 

 countries that ordinarily receive an annual rainfall 

 of twenty inches or less. Irrigation-farming cannot 

 of itself reclaim the arid regions of the world, for the 

 available water supply of arid countries when it shall 

 have been conserved in the Ijest jiossible way cannot 

 be made to irrigate more than one fifth of the thirsty 

 land. This means that under the highest possible 

 development of irrigation, at least in the United 

 States, there will be dve or six acres of unirrigated 

 or dry-farm land for every acre of irrigated land. 

 Irrigati(jn development cannot possibly, therefore, 

 render the dry-farm movement valueless. On the 

 other hand, dry-farming is furthered by the develop- 

 ment of irrigation farming, for both these systems of 

 agriculture are characterized b}- advantages that 

 make irrigation and dry-farming su])plementary to 

 each other in the successful development of any arid 

 region. 



Under irrigaticjn, smaller areas need to be eulti- 

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