CHAPTER IX 

 DRAINAGE 



The work of crop production is nearly all concerned 

 with classes of plants which have been evolved through 

 cycles of ages on soils containing only capillary water. 

 Our field crops, garden crops, fruit, forest and orna- 

 mental trees are nearly all accustomed to soils in which 

 the ground water does not rise within several feet of the 

 surface. The ground water rising to, or nearly to, the sur- 

 face, even for short intervals, reduces the yields of many 

 crops. In very few cases, indeed, are the crops made 

 less productive by systems of drainage which rapidly 

 remove all ground water from the soil to the depth of 

 several feet. 



Taken in its entirety, land drainage is of vast im- 

 portance. There are many large areas, in some cases 

 hundreds of miles across, from which standing water 

 must be removed, or which must be protected from oft- 

 recurring flood water. There are large areas, including 

 a few or many farms, for which drainage systems must 

 be constructed by the voluntary co-operation of the 

 owners, or by the county or state, with cost and benefits 

 equalized among the owners. But the larger total of final 

 expense is the drainage within the millions of farms, 

 whether into a natural outlet or into an outlet provided 

 by large community drains. 



There is great variety of conditions where drainage 

 will pay, ranging from the deep pond to the hillside 

 which, only in occasional years of unusual rainfall is so 

 wet as to reduce crop yields. The wet sloughs, or 

 bottoms, along streams, the nearly level bottom lands, 

 and the heavy clay lands constitute the bulk of the 



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