144 FOOD 



56. Irrigation and Drainage of Farms. 



It often happens, in lands of little rain, even if 

 the soil is well tilled and the mulching well done, that 

 there is not enough water in the soil for the proper needs 

 of the crops. Under such circumstances it is necessary 

 to add water to the farm from some river or well. Any 

 addition of water to land is called irrigation. The soil 

 should always be tilled as soon after irrigating as it 

 becomes a little dry on top. Why? 



Irrigation is of the utmost importance, since about 

 two-fifths of the area of the United States is too dry for 

 farming. Up to the present time a little over ten million 

 acres are irrigated, which is very little compared with the 

 dry area. Proper irrigation, that is, where there are 

 several thousand acres to be irrigated, must be under- 

 taken by the government, since it is impossible for any 

 place to build a large irrigation system. Although the 

 cost of irrigation is great, the large crops more than pay 

 for it, and land, which otherwise would be a desert, 

 blossoms into productiveness. 



Sometimes there is too much water in the soil and 

 it is necessary to remove some of it. This removal of 

 water from land is called drainage. Drainage may be 

 accomplished by ditches and by covered drain pipes 

 which allow the water to enter at the joints. When the 

 pipes are used the drainage is called underdrainage. Un- 

 derdrainage is better than surface drainage as it keeps 

 the water at the proper level and the plants send their 

 roots deeper. Thus the plants have more soil from 

 which to obtain their food and therefore they grow bet- 

 ter. What is the harm of having too much water in the 

 soil? 



