VALUE OP TILLAGE. SUBSOILING. 133 



stituents were in the state of the finest powder. All 

 mineral substances combine with oxygen and with each 

 other the more readily in proportion as they are reduced 

 to more minute particles. 



413. Most people are wholly unaware of the value of 

 tillage. As a general rule, we may say, the more com 

 pletely and frequently the soil is stirred the better. Far 

 mers are apt to think that the great advantage of hoeing 

 and cultivating witli the plough, the harrow and the cul 

 tivator, between rows of corn or other crop, is the destruc 

 tion of weeds. This doubtless is indispensable. But in 

 reality, the improvement of the soil by continually expos 

 ing fresh portions to the air, by thoroughly mixing it, and 

 thus preparing for future crops, is of not less value than 

 the weeding. Though, doubtless, there may be danger 

 of too frequently turning dry soils in a season of drought. 



414. Subsoiling is cultivating with a plough which does 

 not turn a furrow, but penetrates to some distance below 

 the furrow already turned and loosens the soil down 

 there. It sometimes adds one third to the crop raised. 

 By stirring and loosening the earth to a considerable 

 depth, it makes it retentive of moisture to that depth, 

 and, with moisture, of all that accompanies moisture into 

 the earth, and makes it easy for the roots to penetrate and 

 reach them. 



If the roots of a plant do not penetrate so deeply, their 

 food, deep in the earth, reaches them by capillary attrac 

 tion. This draws the moisture, and all that the moisture 

 contains, up towards the surface. A part of it is taken 

 up by the plants, and the remainder, as the moisture 

 evaporates, is left near the surface to be still farther acted 

 upon by the air. 



