Nature-Study Agriculture 



The 



water 



table 



How 

 drainage 

 affects 

 the soil 



FIG. 40. Plowing sod with a tractor. 



surface that the roots are drowned. If we dig a hole a 

 few feet or sometimes only a few inches deep in damp land, 

 we may come to a place where water begins to seep in. 

 (Exp. 5.) The upper surface of this free water which 

 runs out of the soil if it gets a chance is called the " water 

 table." The roots of most farm plants, excepting rice and 

 cranberries, will not grow below the water table, because 

 they cannot get enough air there. For this reason the 

 water table should not be very near the surface of the 

 ground. In sloping, well-drained land there is usually 

 no free water and therefore no water table near the surface. 

 Artificial drainage, by lowering the water table, in- 

 creases the depth to which roots can go and so makes 

 available a larger supply of plant-food material. It 

 helps to ventilate the soil and to make it warmer; it 

 makes the soil looser and lighter and easier to work with 

 farm implements ; and it greatly increases the number 

 of the beneficial soil bacteria. Even though no plant 



