8 VEGETABLE GARDENING. 



water in a good soil due to cultivation was equal to thirty- 

 three per cent of what it contained when not cultivated. This 

 increase, however, is somewhat more than was found in other 

 trials, but in every instance there has been a marked increase 

 in the drought resisting qualities of the soil due to continued 

 cultivation. In some experiments made by Professor Levi 

 Stockbridge in 1878, it was clearly shown that on one occa- 

 sion in eight days of very dry summer weather thorough cul- 

 tivation of the land resulted in saving 256 barrels of water in 

 an acre of heavy loam by preventing- evaporation from its 

 surface. These facts show the great value of cultivation as 

 an aid in irrigating operations. Cultivation of the land or 

 mulching should always go with irrigation. 



Humus is the rotten organic matter in the soil which in- 

 creases its retaining power. On this account new land which 

 contains much organic matter does not suffer as seriously 

 from drought as that which has been cultivated for some time 

 without manure. Likewise, land heavily manured with rotten 

 manure, which becomes humus, has its drought resisting 

 qualities increased, while the application of undecayed man- 

 ure to the land has a directly opposite result until it has 

 been in the soil long enough to become thoroughly rotted. 



Amount of Water Required for Irrigating Different Crops. — 

 Sometimes a very small amount of water applied at the 

 right time will make the difference between a good crop 

 and a total failure, as, for instance, when dry weather comes on 

 just as the strawberry crop is almost ripe, when it has hap- 

 pened 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 supply is needed to 

 mature a crop in dry seasons. In this section a storage ca- 

 pacity 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 

 equals 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 



