Cultivation of Arable Land.—Potatoes. 607

of loamy foils, on the principle of keeping the earth light and open by their very gradual decay, in order that the roots may have room to extend them- felves, many other fubftances befides littery dung have been employed. Wheat ftraw, furz, broom, heath, and other fimilar matters, after having been in fome meafure reduced by chopping, are depofited in the drills, and, from their gra- dual decay, good crops are frequently produced.

Clover, tares, vetches, and other fucculent vegetable produCtions, when en- clofed in the foil in their green ftate, at the time of planting, have alfo been found ufeful as manure in the growing of crops of this kind*.

Peaty or turfy materials have likewife been made ufe of for the fame pur- pofe on different forts of land. On the light, thin, and open foils, they are afferted to have good effeéts, in contributing to the nourifhment and fupport of the crop, in rendering them more capable of retaining moifture, and by in- creafing their ftaple. And in the heavier foils they become of much ufe, by keeping them in a more open condition, and thereby allowing the moifture to pafs off more readily, and the roots of the plants to{well out in a proper manner. It is probable likewife that frefh vegetable earth, and decayed leaves collected from woods or other places, may be of fervice in this way, as well as in the manner that has been mentioned above.

The trials that have been made with lime render it probable that it may be ufefully employed in the cultivation of the potatoe on the ftiffer forts of foils, when combined in a fmall proportion with rich earth and dung; but, in its fim- ple ftate, according to the experiments of Mr. Somerville, it has a tendency to induce the curl; and in the garden culture of this root, we have conftantly found it difadvantageous by producing the canker, whether employed in the effete or{tate of carbonat, or in its more active or cauftic one.

But though lime in its uncombined ftate may not be capable of being made ufe of with much utility; where the pra“tice of paring and burning is had re- courfe to, and there is a confiderable portion of afhes from the combuttion of the fward and the coarfe vegetable produéts upon it, full crops of potatoes may be raifed by the ufe of the afhes alone. In this way, the coarfe unpro- du@tive pafture grounds in various parts of the kingdom, and extenfive tratts of ufelefs wafte lands, may be brought into a{tate of cultivation in an eafy and profitable manner; as after a crop of potatoes, put in in this method, the land will, in moft inftances, be in a proper condition for the growing of grain crops.

* Billingfly, in Bath Papers, vol. VI.