IRRIGATION 



237 



artesian wells or artificial storage reservoirs furnish large 

 supplies of water. Someone has illustrated the limita- 

 tions of irrigation in the great arid West by comparing 

 the whole droughty plains and intermountain areas in 

 which the rainfall is light to a twenty-acre field with 

 one furrow plowed across it, the furrow representing 



Figure 139. Portable engine used for pumping water for flooding rice fields in Texas. 



that proportion of the whole for which the water is avail- 

 able for irrigation. The semi-arid area on which dry- 

 land farming must be carried on is very extensive, and 

 farm management there must be planned to conserve, 

 for the use of crops, the small amount of water annually 

 precipitated. In many places the windmill, or steam or 

 gasoline engine to pump water from wells upon limited 

 areas, as near buildings, will help make possible the 

 development of a homelike farmstead on large ranch-like 



