SUBSOILING FOR MOISTURE CONTROL 



219 



hand, if the subsoil gets dry enough to break up, it may 

 remain so loose and lumpy during the remainder of 

 the season that capillarity is largely destroyed, and 

 crops suffer from shallow rooting and lack of moisture. 

 Decrease in crop yields as a result of subsoiling in spring 

 are frequently reported. On the other hand, subsoiling 

 in the fall, although usually more difficult to accomplish, 

 is more likely to result in benefit. The cloddy condition 

 which may be developed is largely broken down in re- 

 gions of heavy winter rain by the saturated condition. 

 Still the structure does not become nearly so compact 

 as before the treatment, and good results. 



King presents figures which show that, as a result 

 of the application of 1.34 inches of water, the soil which 

 had been subsoiled to a depth of twenty-one inches 

 retained, after a period of four days, 65.6 per cent more 

 water in the surface four feet than the adjacent land not 

 subsoiled. 



Not only is sub- 

 soiling effective to 

 increase the abso- 

 lute water capa- 

 city, but it may 

 strengthen the 

 capillary or film 

 movement to such 

 an extent that an 

 important amount of water is drawn up from the deeper 

 subsoil or from adjacent zones not so treated. A 

 "hardpan" layer below the plow depth may seriously 

 interfere with the upward movement of water and the 



Subsoiler that loosens the subsoil by 

 breaking through. 



