suB-soiLixG, tre:nch plowing, tillage. 49 



Subsoil Plowifl*?. — The ultimate object of this oper- 

 ation IS, of course, the deepening of the soil and loosen- 

 ing the subsoil. This invariably follows from opening 

 the subsoil to the ameliorating influence of the elements; 

 and the beneficial result is due to the accumulation of 

 vegetable matter below the ordinary range of the soil by 

 the roots penetrating deeper and being left to decay in 

 the bed where they have grown. The subsoil plow 

 merely stirs and opens the subsoil : it does not turn a 

 furrow. A common plow goes before, throwing out a 

 large open furrow-slice of the active soil; the subsoil 

 plow follows, entering to a depth of six or eight inches 

 below the bottom of the surface furrow ; and the next 

 furrow of active soil is thrown over the last opened fur- 

 row of the sub-soiler. 



The subsoil implement requires to be drawn by four 

 or more horses, according to the nature of the soil and 

 the depth of working. 



Though of great benefit on land which is sufficiently 

 dry, subsoilmg does more harm than good on wet lands. 

 It is, therefore, only to be employed as an auxiliary to 

 draining, and not as a substitute for it. Some time must 

 elapse, however, between draining and subsoiling. When 

 properly done it increases nearly every good effect of 

 underdraining. Especially does it diminish injury by 

 drouth, by loosening the soil and admitting air to cir- 

 culate among the particles of the subsoil and deposit its 

 moisture. It deepens the soil, and renders available 

 matters v/hich are perhaps deficient in the surface soil. 

 It also improves the drainage. 



Trench or Deep Plowing. — This is advantageous to 

 such lands as are of the same nature to a considerable 

 depth. For those lower parts of the soil, which have 

 become filled with manure which the rains have carried 

 down below the surface, are thus thrown up, to contrib- 

 3 



