THE SOIL 17 



free circulation of the air. These valuable crops cannot 

 do this when the soil is wet and cold. 



Sandy soils with sandy subsoils do not need artificial 

 drainage ; these soils are naturally drained. With clay soils 

 it is different. It is very important to remove the stagnant 

 water in them and to let the air in. 



When land has been properly drained, the other steps in 

 improvement are easily taken. When soil is dried and 



FIG. 10. A TILE IN POSITION 



mellowed by proper drainage, then commercial fertilizers, 

 barnyard manure, cowpeas and clover can each most readily 

 do its great work of improving the texture of the soil and 

 of making it a cosy home for plants to grow in. 



Tile Drains. Tile drains are the best and cheapest that 

 can be used. It would not be too strong to say that 

 draining by tiles is the perfection of drainage. Thou- 

 sands of practical tests in this country have demonstrated 

 the value of tile draining for the following reasons : 



