Surface Drainage. 



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cropping. The better plan would be to utilize the ground 

 with a crop which would endure the shallow drainage. 



385. Lands Requiring Surface Drainage. There are 

 many wide stretches of very flat land which can only be 

 drained through surface channels. Such are the districts 

 which in recent geologic times were lake bottoms, over 

 which a heavy sheet of close textured clay was deposited. 

 Soils like these have subsoils so close that were there plenty 

 of fall and good opportunity to find outlets for drains the 

 rains could not reach the drains freely enough to meet the 

 needs of crops. 



Fio. ISO. Plan for drainage of lands of the Illinois Agricultural Company, 

 Rontoul, Illinois. (After J. O. Baker.) The smallest squares are 40 

 acres; double lines show open ditches; single lines are tile drains. 



Such fields must be plowed in narrow lands with the 

 dead furrows in the direction of greatest fall in order to 

 provide a quick removal of the surplus rains. 



Other districts are so flat that the rains have not yet 

 been able to cut sufficiently deep river channels to drain 

 the fields enough for agricultural purposes. The soil may 

 be porous enough, even a coarse sand, and yet for lack of 

 natural drainage channels remain too wet to till. 

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