448 EUROPEAN AGRICULTURE. 



its place ; but in no instance was its previous fertility restored. 

 Deep cultivation will undoubtedly in the end recover such places, 

 but time and patience are indispensable. 



7. SUBSOIL-PLOUGHING. The next great operation, performed 

 with the plough, is here called subsoiling. The object of this 

 is similar to that of trench-ploughing that of loosening the sub 

 stratum, and deepening the soil to be cultivated. But it differs 

 in this respect : trenching, either by the spade or the plough, 

 buries the surface soil, and covers it with that which is turned 

 up ; but subsoil-ploughing aims to loosen the substratum to the 

 depth required, without bringing it to the surface or covering 

 the mould, and, by the gradual intermixture of the lower stratum 

 with the upper soil, to enrich it, and ultimately convert the whole 

 into an equally arable and fertile condition. Subsoiling is per 

 formed by a plough of a peculiar construction, following in the 

 furrow of a common plough. If we suppose the first plough to 

 have turned up the land to the depth of seven inches, the next 

 plough loosens it to the depth of nine inches more, so that the 

 whole land ploughed is in this case equal to sixteen inches. 

 The great objection to trenching land, either by the plough or 

 spade, is, that it brings the inert soil to the surface in a condition 

 unsuited to the purposes of vegetation, and that thus much time 

 is necessarily lost before it can, without great expense, be 

 restored to its former fertility. The advantage of subsoiling is, 

 that it so gradually raises the substratum to mingle with the top 

 soil, that the cultivation of the latter is not interrupted, but the 

 soil is benefited by the slight intermixture. Another and very 

 great advantage derived from subsoiling, is in the admission of 

 air and heat to the loosened soil, by which it is improved, and 

 better subserves the purposes of vegetation, and at the same time 

 opportunity is given for the free expansion of the roots of the 

 plant. On many descriptions of soil, the surface, or vegetable 

 mould, rests upon a hard pan at greater or less depth, and which 

 is impervious to the roots of the plant, and does not suffer even 

 the water to pass off freely. However long this may have 

 existed, as the plough has usually gone only to a certain depth, 

 this substratum has become the more indurated by the treading 

 of the horses in the ploughed furrow, and the constant sliding 

 of the sole of the plough over it. It is the object of the subsoil- 



