158 THE WHEAT CULTUEIST. 



" 2d. It increases very largely the supply of nutriment, 

 by allowing the access of air, and by the process of 

 weathering, acting upon the mineral elements of the 

 soil. 



4 



" 3d. It preserves an equal quantity of moisture in the 

 soil. We seldom have a rain so great as to produce an 

 unhealthy stagnation of water about the roots of plants 

 set in a soil seven or eight inches deep, and, on the con- 

 trary, we seldom have a drought of so long continuance 

 as to extract all the moisture to that depth. 



" These, and other known advantages from deep 

 ploughing, we might dwell upon ; and apart from the well- 

 known fact above alluded to, it would hardly be supposed 

 that any crop, of whatever character, would be exempt- 

 ed from the good influences of the practice. 



" We must make a proper distinction, however, be- 

 tween a natural subsoil, indurated and rendered imperv- 

 ious to the action of the air by centuries of rest its orig- 

 inal hardness and impenetrability aggravated by a long 

 course of continuous treading, in ploughing the surface 

 soil and that firm, mellow body of earth, which is pro- 

 duced by deep cultivation. 



" It is this firm, yet generous subsoil, which forms so 

 valuable a matrix for the roots of the wheat plant, and 

 enables them to resist the loosening effects of alternate 

 frosts and thaws during winter. This important dis- 

 tinction, it will be observed, allows nothing to be 

 detracted from the argument in favor of deep ploughing. 

 It is only when the previous working has been, indeed, 

 most thorough, that the wheat reaps a due advantage 

 from the shallow ploughing. The understratum, though 

 somewhat compacted in comparison with the loose sur- 

 face soil, is so enlivened by the former breaking up, 



