Subsoil. 35 



dry, by the moisture either sinking or evaporating, than 

 when the subsoil is clay, or any retentive substance. If the 

 rock next the soil is sandstone, it will allow the water to fil- 

 ter ; but the soil over that species of rock is never of the 

 best quality. Soil resting on whin-rock, or on limestone, is 

 never much hurt by moisture, as the latter sinks into the 

 rock, and the soil is always of much better quality, than si- 

 milar soil resting on till or on freestone ( ia3 ). 



2. A porous subsoil, is uniformly attended with this ad- 

 vantage, that by its means, all superfluous moisture may 

 be absorbed ( ia4 ). In regard to its allowing the fibrous 

 roots of vegetables to extend deeper in search of moisture 

 or nutriment, that is often pernicious rather than otherwise, 

 and must be checked by the useful operation of treading. 



Below clay, and all the varieties of loam, an open sub- 

 soil is particularly desirable. It is favourable to all the 

 operations of husbandry ; it tends to correct the imperfec- 

 tions of too great a degree of absorbent power in the soil 

 above ; it promotes the beneficial effects of manures ; it 

 contributes to the preservation and growth of the seeds ; 

 and ensures the future prosperity of the plants ( ias ). Hence 

 it is, that a thinner soil, with a favourable subsoil, will pro- 

 duce better crops, than a more fertile one, incumbent on 

 wet clay, or on cold and non-absorbent rock. 



Lands whose substratum consists of clean gravel, or sand, 

 can bear little sun, owing to their not having the capacity 

 of retaining moisture, and their generally possessing only a 

 shallow layer of vegetable mould. In England, this soil 

 was formerly called rye-land, being more generally cropped 

 with that species of grain, than any other. When such soils 

 are cultivated for barley, they should be sown early, before 

 the ground becomes very dry ; and if it becomes so, the seed 

 should be abundant, and steeped for two or three hours in 

 water, or in the juice of a dung heap, that its simultaneous 

 germination, and ripening at the same time, may be secur- 

 ed( lz6 }. 



When soils with a retentive bottom, are either in fallow, 

 or preparing for a green crop, the miner should follow the 

 common plough. This is a species of plough not mounted 

 with mould-boards, for it is intended merely to loosen the 

 subsoil, and not to raise it. When the subsoil is thus loosen- 

 ed, it absorbs the wet. In process of time, the manure gets 

 to that loosened earth, improves it, and in a few years, the 

 productive soil is enlarged. 



c 2 



