710 PRACTICE OF AGRICULTURE. Part III. 



vated on chalky soils, are pease, turnips, barley, clover, and wheat ; and however much the 

 soil is exhausted, it will produce sainttbin. 



4390. Chalky soils are in general Jitter for tillage than for grazing; for without the 

 plough, the peculiar advantages derived from this soil by saintfoin, could not be obtained. 

 The plough, however, ought not to extend to those fine chalky downs, (called ewe leases 

 in Dorsetshire), which, by a very attentive management during a number of years, have 

 been brought to a considerable degree of fertility as grazing land, and which are so use- 

 ful to sheep in the winter season. A chalky soil that has been in tillage, permits water 

 to pass through it so freely in winter, and is so pervious to the sun's rays in summer, that 

 it is the work of an age to make it a good pasture of natural grasses, more especially when 

 the chalk lies near the surface. Hence, in the western counties of England, several 

 thousands of acres of this soil, though not ploughed for thirty years, have scarcely any 

 grass of tolerable quality upon them, and are literally worth nothing. Such soils ought 

 to be laid down with saintfoin. 



4391. Alluvial soils are of two sorts; one derived from the sediment of fresh, and the 

 other of salt water. Along the sides of rivers, and other considerable streams, water- 

 formed soils are to be met with, consisting of the decomposed matter of decayed veget- 

 ables, with the sediment of streams. They are in general deep and fertile, and not apt to 

 be injured by rain, as they usually lie on a bed of open gravel. 1 hey are commonly em- 

 ployed as meadows, from the hazard of crops of grain being injured, or carried otF by 

 floods, if cultivated. 



4392. Alluvial soilSy arising from the operations of salt water, called salt marshes in 

 England, carses in Scotland, and polders in Holland and Flanders, are composed of the 

 finest parts of natural clay, washed oflPby running water, and deposited on flat ground, on 

 the shores of estuaries, where they are formed by the reflux of the tide, and enriched with 

 marine productions. They generally have a rich, level surface, and being deep in the 

 staple, they are well adapted for the culture of the most valuable crops. Hence wheat, 

 barley, oats, and clover, are all of them productive on this species of soil; which is like- 

 wise peculiarly well calculated for beans, as the tap-root pushes vigorously through it, 

 and finds its nourishment, at a great depth. From the great mass of excellent soil, the 

 fertility of these tracts is nearly inexhaustible ; but from their low and damp situations, 

 they are not easily managed. Lime, in considerable quantities, is found to answer well 

 upon this species of soil. 



4393. The term loamy soilis applied to such as are moderately cohesive, less tenacious 

 than clay, and more so than sand. Loams are the most desirable of all soils to occupy. 

 They are friable; can in general be cultivated at almost any season of the year; are 

 ploughed with greater facility, and less strength than clay ; bear better the vicissitudes of 

 the seasons ; and seldom require any change in the rotation adopted. Above all, they are 

 peculiarly well adapted for the convertible husbandry; for they can be changed, not only 

 without injury, but generally with benefit, from grass to tillage, and from tillage to 



4394. As to the comparative value of soil, it has been justly remarked, that too much 

 can hardly be paid for a good soil, and that even a low rent will not make a poor one pro- 

 fitable. The labor of cultivating a rich and a poor soil, is nearly the same; while the 

 latter requires more manure, and consequently is more expensive. Poor soils, at the same 

 time, may have such a command of lasting manures, as lime or marl, or even of tempo- 

 rary sorts, like sea-weed, or the refuse of fish, as may render them profitable to cultivate. 

 It is a wise maxim in husbandry, that the soil, like the cattle by whom it is cultivated, 

 should always be kept up in good condition, and never suffered to fall below the work it may 

 be expected to perform. 



Sect. III. Of Subsoil relatively to the Choice of a Farm. 



4395. On the nature of the understratum depends much of the value of the surface soil. 

 On various accounts its properties merit particular attention. By examining the subsoil, 

 information may be obtained in regard to the soil itself ; for the materials of the latter are 

 often similar to those which enter largely into the composition of the former, though the 

 substances in the soil are necessarily altered, by various mixtures, in the course of cultiva- 

 tion. The subsoil may be of use to the soil, by supplying its deficiencies, and correcting 

 its defects. The hazard and expense of cultivating the surface are often considerably 

 augmented by defects in the under- stratum, but which, in some cases, may be remedied. 

 Disorders in the roots of plants are generally owing to a wet or noxious subsoil. Subsoils 

 are retentive, or porous. 



4396. Retentive subsoils consist of clay, or marl, or of stone beds of various kinds. 

 A retentive, clayey subsoil is in general found to be highly injuriouSi The surface 

 soil is soaked with water, is ploughed with difficulty, and is usually in a bad con- 

 dition for the exertion of its vegetative powers, until the cold sluggish moisture of 



