THE VEGETABLE GARDEN 19 



it has happened that so small a quantity as 600 barrels of 

 water per acre has been sufficient to ripen the crop. In 

 western Kansas it is estimated that a storage capacity of 

 5,000 barrels per acre in addition to the ordinary rain sup- 

 ply is needed to mature a crop in dry seasons. In this 

 section a storage capacity of 1,500 barrels per acre would 

 probably be enough to insure against serious injury from 

 drought in any but very exceptionally dry years. Enough 

 water to cover an acre one inch deep is termed an acre inch. 

 About 900 barrels equal one acre inch. 



Pumping Water for Irrigation. Where valuable crops 

 are grown, it will sometimes pay to pump water for them. 

 There are many localities in this section where a large 

 amount of water may be controlled by lifting it less than 

 thirty feet. In such places windmills may be successfully 

 used for pumping the water, providing reservoirs of large 

 capacity can be cheaply made into which water may be 

 pumped the year around to be used as needed. Thresher 

 engines, which are seldom used except in the late summer 

 and fall, may sometimes be used to advantage for pumping 

 water and often at very low cost. Gasoline engines are 

 used in many irrigation works. They are very desirable 

 and in fact necessary on any farm where power can be used. 

 They are useful not only for pumping water but for grind- 

 ing feed, sawing wood, etc. In putting in a pumping 

 plant the pump should be put as near the water supply as 

 possible. 



Reservoirs should be on some elevated point. They are 

 easily made by digging out the earth and puddling the 

 bottom and sides with thick clay, which should be at least 

 one foot in thickness and well packed when wet. A good 

 way to pack it is to drive horses over it. When clay cannot 

 be obtained the bottom may be made tight with a thin coat- 



