INFLUENCE OF CULTIVATION 33 



deep, and the finer the condition in which the surface 

 soil is left, the better. 



Shallow surface cultivation should be resorted to as 

 a means of conserving soil moisture. It can be prac- 

 ticed in connection with deep plowing, shallow plow- 

 ing, snbsoiling, or rolling ; in fact, it can be combined 

 with any method of preparing the land. Shallow sur- 

 face cultivation does not mean that the soil should not 

 be previously well prepared by thorough cultivation. 

 The following example shows the extent to which 

 shallow surface cultivation may conserve the soil 

 water. 13 



Per cent, of water in cornfield. 

 With shallow sur- Without shallow 

 face cultivation. surface cultivation. 



Soil, depth 3 to 9 inches 14.12 8.02 



Soil, depth 9 to 15 inches 17.21 12.38 



27. Cultivation after a Rain. — When evaporation 

 takes place immediately after a rain, not only is there 

 a loss of the water which has fallen, but there may 

 also be a loss of the subsoil water by translocation, if 

 nothing be done to prevent. 12 The following example 

 shows the extent to which the subsoil water may be 

 brought to the surface. 13 



Per cent, of water. 

 Surface soil. Subsoil. 



1 to 3 inches. 6 to 12 inches. 



Before the shower 9.77 18.22 



After the shower 22.11 16.70 



The rainfall was sufficient to have raised the water 

 content of the surface soil to 20.77 per cent. The 

 subsoil showed a loss of 1.52 per cent., while the sur- 



