266 



THE PRINCIPLES OF SOIL MANAGEMENT 



surface. In some sections of the country where the 

 wetness is most serious in the spring, the crops are 

 planted on ridges which are sufficiently raised above 

 the general surface to be drained; and, by the time the 

 roots are ready to penetrate deeply, the excess of moist- 

 ure will have been removed by percolation and evapo- 

 ration. 



Crops of any sort, including weeds, green manures 

 and cover-crops, may serve to dry the soil by evaporating 



Fig. 96. The nine foot evener used in the final filling of the ditch by the 

 use of the turning plow after laying drain tile. Care should be exercised in 

 placing the first covering of earth over the tile not to disturb their alignment 

 or break any of the sections. This is best accomplished by hand, and the earth 

 should be carefully pressed around the tile. 



water from their leaves. It has been seen (page 134) that 

 the amount of water so used is large because of the 

 functional activity of the plants and the large surface 

 which they expose. Growing crops expand the evapo- 

 rating surface of the soil and are especially useful in 

 removing a temporary wetness in the spring. 



The application of any of the above methods for the 

 removal of water must be guided by the local conditions 

 of soil, season, climate, crop and system of farming. 



