330 MAN'S USE AND CONSERVATION OF SOILS 



In this kind of farming the aim is to use more than one 

 year's moisture in growing a crop. 



Crops are usually planted only every other year, two 

 years' moisture being retained for one crop. The soil is, 

 however, kept thoroughly cultivated all the time. Of 

 course plants requiring the least amount of moisture are 

 best adapted to dry farming. 



IRRIGATION IN SQUARES 



Irrigation is the most efficient means of raising crops in 

 regions of insufficient rainfall or of droughts. Water is 

 brought to the land from distant sources, or from flowing 

 artesian wells, or is pumped from wells which have been 

 sunk to an available water table. In this way water can 

 be supplied to plants whenever needed. Where the ground 

 is quite level it is often flooded, sometimes in larger or smaller 

 squares, with little ridges separating the squares. A great 

 deal of water is lost in this way by evaporation. 



