That country abounds much in the calcareous matter denominated chalk, which is also converted into lime by calcination, and used as a manure. It forms a weaker sort of lime. As this substance, however, is hardly to be found in this country, it will be unnecessary further to speak of this manure.
Gypsum, (sulphate of lime) is a most powerful stimulant to the growth of many crops in all dry soils in this country, but with the following exceptions: it has no sensible effect on lands newly cleared, on those in the vicinity of the ocean, nor on those which have been completely exhausted by severe cropping. In soils of this latter description, some pabulous matter must be given them for the gypsum to digest or act upon; and this may be a previous manuring with lime, marl, bog-earth, barn dung, or perhaps any substance that is calculated to improve the condition of the soil. It should also be observed that the application of gypsum frequently fails entirely of producing its effects if followed by uncommon drought, or unusually wet weather. It is generally most powerful when applied to growths of leguminous plants, to those extending in vines, such as the various species of the gourd tribe, the strawberry, &c. and to several sorts of the green crops, particularly potatoes, clover-grasses, lucern, &c. On fibrous rooted grasses, and those grain plants most nearly related to them, such as wheat, rye, oats, barley, &c. it has no sensible effect when applied as a top dressing to the growing plants. On Buckwheat it is very powerful, and for Indian corn it is also valuable. Judge Peters, (of Penn.) whose experience of its uses has been long and extensive, says that although he has found this manure of little use to many sorts of plants, when applied to them as a top dressing, yet he has invariably found that all plants derive benefit from their seeds being rolled in gypsum, after being soaked in some liquid, before sowing or planting. As a manure, however, for wheat or grain crops of similar kinds, immense benefit may be derived from it by applying it to the sward, as a top dressing, a suitable length of time before the ground is broken up. In this way two bushels of gypsum may be made to give an additional increase of eight or ten bushels of wheat to the acre. Take, for instance, land which in its natural state, and with the usual culture, will only yield ten bushels of wheat to the acre; in the fall or early in the spring, give it a top dressing of two bushels of gypsum to the acre; by the middle of June following, the land will exhibit a fresh green sward, principally of white clover; and when land is thus clothed in verdure, it is a sure indication of a great addition to its fertility, and that a good crop may then be expected. When, therefore, the green sward is thus formed, turn it under, and then, with the usual culture, twenty bushels of wheat to the acre may be expected, where only ten would have been had without this previous enriching of the ground by the application of gypsum. Yet the same quantity of this manure, applied as a top dressing to the growing crop of wheat, would have had no sensible effect. It should therefore be understood, that for all growths which derive little or no benefit from gypsum, when applied as a top dressing to the growing plants, the ground should be previously enriched by applying this manure to the sward, a suitable length of time before it is to be broken up, which length of time will usually be from two to three months. At all events as soon as the sward fully exhibits the effects of the gypsum it may then be turned under. Wherever a sward is to be turned under, this practice should be invariably pursued in order that the ground be rendered more fruitful for the crop that is to follow.
In this country gypsum is a great source of wealth, wherever soils are sensible to its effects. It has tended much to equalize the value of lands, by imparting an artificial fertility to those naturally more sterile, and that at a small expense.—But gypsum alone is by no means a sufficient source of dependence as a manure for keeping lands in the improved condition that is necessary for raising the best crops, and of course deriving the greatest profits. The farmer should attend also to making the most of such other manures as come conveniently within his reach. We are, however, no advocate for obtaining manures at any price; they may cost too much; but almost every farmer whose lands are of suitable quality, and who stocks them with as many cattle as he can keep in good order, and then makes the best use of the manure they afford, may usually, with this supply, and with the judicious use of gypsum, added to good culture, keep his lands in an improving condition.
But some soils are so constituted as to be of diminished value without a suitable mixture of other earths than those of which they are composed, and in such case are permanently benefited by such additions of earthy substances. If lands, for instance, are too sandy, or gravelly, the addition of clay to them, or what is better, of upland marle, will permanently improve the soil; and where these earths can be found within reasonable distance it will usually be labour well expended in making such applications. We will state a case in point. In the rear of the city of Albany lies an immense body of calcarious earth, which may properly be called a schistic marle. It is commonly called blue clay. This, when mixed with a due proportion of sand, forms a very fertile and durable soil. Farther west of the city lie large tracts of sandy lands, which require suitable proportions of this marle to render them fit for good culture, and with such additions much of them would be found very valuable. Where they lie sufficiently level, and are not too sandy, it will probably be found that from half a ton to a ton for every rod square would be sufficient to render them very fertile, and fitted for the most profitable rotations of crops.
This sort of marle, which may be found in various parts of the country, and very frequently under tracts of sandy lands, is a very valuable and permanent manure in all dry soils which are deficient of calcarious matter, and have not already too great a proportion of clay in their composition. This manure should be laid on the land as a top dressing, in order that it may be completely pulverized before it is mixed with the soil.
Upland marle is sometimes found of silicious texture, in which case it is good for stiff soils, as well as for others. It is also found of different colours, when combined with argillaceous matter, and of different qualities; that containing most lime or calcarious matter being always the best. Marles of this description are often very valuable in forming a principal ingredient in composts, of which we shall presently speak, and the same may be observed of the superior sorts of this manure found in bog swamps, of which something shall now be said.
This sort of marle is found, at greater or less depths, beneath the surface of many bog swamps, and is of a whitish, a greyish, or a brownish colour. The whitish is the most powerful, having most lime in its composition; the greyish is next in quality. The super stratum is either a bog earth, to wit, vegetable matter totally decomposed; or it is a peaty substance, or vegetable matter in a partial state of decomposition. The bog earth is good manure of itself, and may be used separately, or mixed with the marle; the peaty substance must undergo a further decomposition before it is rendered valuable as a manure, it being then rendered similar to bog earth. These manures when applied to growing crops are somewhat similar in their effects to those of gypsum. They are valuable as top dressings, or for mixing with the soil. Their effects are very powerful on Indian corn, and they are more or less valuable when applied to almost every sort of upland crop, with the exception of wheat, rye, barley, &c. For these they are to be applied to the sward, a suitable time before breaking it up, as has been mentioned in regard to gypsum. It should, however, be observed, that neither decomposed peat, nor bog earth, should be applied to soils which already contain too great a proportion of decomposed vegetable matter.
The condition of clay soils is also permanently improved by mixing a due proportion of sand in them. The most durable and perfect soil is chiefly composed of certain proportions of sand, clay, lime, and vegetable matter in a state of decomposition, and, whenever any soil is destitute of a due proportion of any of these, the addition of such earthy substance can never fail to serve as a manure.
The stony earth called Pyrites, when pulverised by the aid of a proper degree of calcination, is much used; and highly esteemed in Flanders as a top dressing for grass lands, as is mentioned in a communication of the late Chancellor Livingston to the Society for the promotion of the useful arts in this state. We will refer the reader to the 2d vol. published by that Society for the manner of preparing this manure, and the quantity to be used, &c.