MANURING, in horticulture, requires to be considered in a some what different light from that process as applied to agricultural purposes. This is necessary because of the variety of plants, pos sessing different constitutional habits, to which the gardener is required to turn his attention, end also because of the different remits which are expected in horticulture and agriculture. In preparing the present article, the writer has confined himself to simple practical facts, and has adverted only ocsa-ionally to chemical explanations.
The gardener is called upon to cultivate species from almost every kind of soil on the surface of the globe, intermediate between the shifting sands of the desert and the most fertile alluvial land con tinually enriched by the decay of vegetable and animal substances. It is therefore obvious that considerable caution is requisite in applying manure, and in determluing the quantity or quality suited to the respective constitutions of the various subjects which the horticulturist takes under his care. Thus, although many plants can scarcely receive too much manure, others, such as the resinous trees, may be actually killed by it.
The kind of manure chiefly used, and frequently the only kind procurable by the gardener, is that derived from the farm-yard, con sisting chiefly of the dung of horses or of horned cattle, more or less mixed with litter. Formerly it was very generally the custom to take advantage of the heat resulting from the fermentation of such dung In hot-bed forcing, and there are still some objects for which this kind is found preferable [Hor-Ben]; but since the hot-water system of heating has received so many improvements, the continued fermentation and consequent degree of decomposition which dung undergoes In hot-beds is rendered a less Important means of obtaining artificial warmth, and consequently it becomes the more important to inquire whether manure is most beneficially applied in a Mate of decomposition, as some have advocated, or in a state as recent as possible, no fermentation being permitted previous to its deposition in the soil.
If dung contains a large proportion of litter, and particularly If the latter be in a dry state, It will be advisable to subject it in nearly all cases to a moderate degree of fermentation, assisted by a auflicient quantity of moisture, in order that the fibre of the straw may bo reduced to a state permeable by the epongiolos of plants, and either become aulEciently dissolved fur of nourishment itself, or serve in the first Instance as an absorbent reservoir for substauces of still greater solubility. 11 here such preparation has not been attended to, later has been frequently observed, when turned out of the ground after a dry summer, to be still In a dry ninety state, having evidently been of little benefit to the crop ; and In the case of many plants, Which require much manure, litter in this ratite would actually prove very injurious. But if the dung be what Is termed short, containing little straw, and that well saturated with the liquid proceeds of the stalls, jt may be dug In without fermentation for most k itchenlarden crops, provided it is well divided and properly mixed with the soil in digging or trenching in. This is necessary in all easel, but more espe
cially so when the manure is applied froth ; for disease is often induced by the roots entering into masses constituted of particular substances which either wholly or, at all events, too powerfully predominate over the proper nutritive solutions.
But, on the other hand, if the soil is of a wet and stiff nature, then long unrotted clung is most proper, because Its straws form so many minute drains, which, to speak technically, keep the ground upon; and in such soils, by means of Jittery manure and drilling, 0 crop of potatoes, for example, can be raised very superior in quantity and quality to that obtained from the application of rotten dung. In this case the previous reduction of the fibre of the straw is not requisite; for the moisture of such soils is sufficient to effect this by degrees, and whilst the process of growth is going on. The authority of Miller may be adduced on this subject ; in his ' Gardener's Dictionary,' he observes, " In very cold moist land, I have frequently seen new horse-dung buried as it came from the stables, and always observed that the crops have suc ceeded better than where the ground was dressed with very rotten dung." On the other hand, dung that has been moderately fermented, and frequently turned over, so as to be easily cut with a spade, is the most proper for such trees as require manure, or for slow-growing crops, where the roots have to remain for years in contact with it. With regard to trees and many perennial plants, no more injury would be incurred by using fresh dung instead of rotten, for the first season, or rather whilst vegetation continued active; but after the roots become nearly dormant, canker or disease of some sort is apt to ensue. The roots may have grown luxuriantly during the summer ; but when they are arrested by the approach of winter,deeomposition will still be going on amongst the materials on which they feed, and these materials may perhaps be chemically changed, before the roots are again called to action These remarks relate chiefly to the description of manure which is most generally used. Other substances which are or may be success fully applied to promote the growth of vegetation are exceedingly numerous. al Anim su stances are very powerful manures, and require to be attenuated or diluted before plants can derive nourishment from them, or in fact before either roots or tops can be safely brought within their contact. If the roots of a plant be wholly immersed in oil or iu blood, that plant will be destroyed. Blood is one of those liquid manures which is occasionally supplied to plants so situated as to render bulky manure inapplicable; but it should unquestionably be copiously diluted with water, and be allowed to rut in compost. Bones are another form of anintal matter much employed,and of considerable energy, especially in calcareous soils, provided they are reduced into small fragments and fermented before being used Gardeners often use them in that state ; and now, as dissolved in sulphuric acid, they are, of course,as available in the garden as in the field.