60 AGRICULTURE 



Sources of water supply. Water for irrigation pur- 

 poses is secured from a variety of sources, such as artesian 

 wells, canals, reservoirs, streams, lakes, and sometimes 

 from the regular wells from which the water is pumped 

 by windmills, electricity, steam or other power. 



TOPICS FOR INVESTIGATION 



1. What is the acreage of irrigated land in your 

 state? What are the possibilities for profitable extension 

 of irrigation to include additional territory? 



2. If there is aridity in your region what is the cause 

 location of mountain ranges, elevation, direction of prevail- 

 ing winds, and other unfavorable seasonal distribution or 

 rainfall ? 



3. Make a study from state and federal sources of the 

 reclamation projects of your state, and write an account of 

 the same, giving area affected, cost, and methods pursued as 

 to supply and distribution of water. 



3. Systems of Irrigation 



There are now in use in various sections of the coun- 

 try three different systems of irrigation. These are known 

 as the surface, sub-surface and overhead systems. 



Surface irrigation. This is the system in most com- 

 mon use, not because it is always the most satisfactory and 

 efficient, but because it can be installed with the least labor 

 and expense. Where water is scarce, or the rental is high, 

 surface irrigation is wasteful, since a large amount of wa- 

 ter is lost by evaporation and by running off into fields, 

 lowlands or streams where it is not needed. And in irri- 

 gation territory water has a direct money value and should 

 be handled as economically as possible. 



Application of water in surface irrigation. The 

 method to be followed in surface irrigation depends on the 

 source of water supply, the physical condition of the soil, 



