21 FIELD AND LABORATORY STUDIES OF SOILS 



Discussion: The freezing of water is one of the natural 

 agencies which plays an important part in the breaking 

 up of the rocks to make soil. This same force can be 

 utilized to good advantage every year by the farmer through 

 the practice of fall and winter plowing. Heavy clay soils 

 b}^ this practice can be made more loose and friable. Ex- 

 posure of the plowed land to the action of freezing and 

 thawing is especially desirable where the soil has become 

 hard and cloddy, as the result of plowing it too wet, or by 

 the trampling of livestock. The hard clods absorb water 

 which, on freezing, expands and bursts them apart. 



