4G8 



THE PRINCIPLES OF SOIL MANAGEMENT 



which increases the number of lines of weakness in the 

 soil structure facilitates the action of the moisture 

 films in solidifying the soil granules. Tillage shatters 

 the soil and breaks it into many small aggregates of 

 particles, which may be further drawn together and 

 loosely cemented by the further evaporation of moisture. 

 The more numerous the lines of weakness produced, 

 the more pronounced the granulation; and, conversely, 

 the fewer the lines of weakness which result, the more 

 coarse and cloddy the structure. 



Fig. 129. The modern sulky riding plow. 



333. Implements of tillage. The number of imple- 

 ments adapted to the manipulation of the soil is very 

 large, and they embrace many types and patterns. 

 Many operations are comprehended by the term tillage. 

 It includes the use of all those implements which are 

 used to move the soil in any way in the art of crop-pro- 

 duction. It includes the smallest hand implements, as 

 well as the largest traction implements. 



334. Effect on the soil. All these operations may be 

 divided into two groups, according to their effect on 



