UNDERDRAINING. 



79 



Subsoil ing 

 Clay Lands. 



Proper drainage of the land forms the very basis 

 of successful agriculture. The soil may be ever so 

 rich, but ^vithout sufficient drainage, either natural 

 or artificial, its production can never reach the limit 

 )f what is possible. 



It is seldom necessary to drain high, dry land. 

 Deep subsoiHng before seeding for either hoe or 

 grain crops on such land gives very good results, 

 especially on a clay subsoil. It improves the 

 physical condition of clay soils by allowing the 

 surface water to percolate into the subsoil and the 

 air to circulate freely. A sandy or gravelly subsoil 

 does not require loosening. 



The bacteria, or germs, necessary to decompose 

 the vegetable matter can act only in dr\', warm soil. 

 Therefore, to get the best results, it is necessary to 

 underdrain wet lands, as they are usually too cold. 



Underdraining removes the surplus water in 

 early spring, and, by causing this surplus to per- 

 colate through the soil to the drain, makes the land 

 porous, and thus tends to retain moisture during the 

 period of drought when it is needed. 



For underdraining there is nothing more suitable size of Drain, 

 than the ordinar>^ round tile. Careful judgment 

 should be used in the selection of the size of this, as 

 the cost of underdraining is governed largely by the 

 size of tile used. 



For a main drain, in ordinary cases five or six- 

 inch tile may be used for the lower end and four-inch 

 for the upper portion; two and one-half iifch to 

 three-inch tile should be used for the laterals, or 

 branches. 



Drains should be from two and one-half to three 

 feet deep. The distance apart between the laterals 

 is governed by the quantity of water to be carried off 



Where Drains 

 are Needed. 



Effect of 

 Underdraining. 



Depth of 

 Drains. 



