TO STUDY THE NECESSITY FOR SOIL DRAINAGE 35 



in time completely saturate the soil if no drainage were 

 possible. The more nearly level the land the more readily 

 does the rain pass into it. During a long-continued rain 

 the water soaks into the soil until, like a blotter or a sponge, 

 it can hold no more. Then the excess of water will flow 

 over the surface to the lowest points in the field and finally 

 join the creeks and rivers which are a part of Nature's 

 great drainage system. 



The water which has soaked into the soil gradually 

 passes into the subsoil and eventually finds its way to the 

 streams. If the soil is a loam with an open subsoil, this 

 natural drainage will be sufficient. However, in heavy 

 loams and in clay soils Nature does her work too slowly 

 to be of immediate benefit. Then it is that w^e should 

 supply artificial drainage in the form of tile to carry away 

 the surplus water more promptly and thus assist Nature. 



