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That a Tap Root or any other Root is peculiarly adapted to supply any particular branch or part of a tree, I very much doubt; but should this be the original arrangement in the system of nature, experience proves that it is not an invariable law, for if a part of the branches of a tree be lopped off, the sap which those would have consumed, is given to the remaining branches, and they are proportionally increased. Whenever part of the Root is taken off, it does not affect any particular branch, but the whole of the branches are equally affected .by the privation and loss; and although cutting off the Tap Root may, by lessening the supply of moisture, produce the same effect as an extended surface of branches, and incline a tree to vary the vertical growth of its branches at an earlier period, yet it is proved in every nursery-ground that all young Plants of erect-growing Trees, are inclined to form their strongest branches in a perpendicular position, and if not obstructed, to throw out its whole strength into one stem, until it attains a height proportioned to its nature and supply of food, and this even after the Tap Root is removed.
The effect intended by pouring water into the pit on transplanting, as here explained, is undoubtedly desirable, but it will seldom be produced by such means.
A great quantity of water poured on will often cement or encrust the earth, and render it so close and adhesive, that it will obstruct the emission of fresh radicles, or the progress of the old ones,
and the Plant in consequence will be much injured.
Water in those cases should be applied a little at a time and often ; this will afford sufficient moisture, and keep the soil loose.
Mould may be a good thing thrown into the pit in the quantity here mentioned, about the Roots of Forest Trees when planted, but it must be improper for Fruit Trees; for by retaining a large portion of moisture, it will oppose fructification, and endanger their health, or by affording a luxuriant supply of food, the Roots may be made to increase rapidly in size, but form few in number. A few large Roots running deep and spreading wide, may be necessary to produce a large Timber Tree, but it will be prejudicial to a Fruit Tree, for, as before observed, those trees are always more prolific when the Roots are much divided or fibrous, and kept near the surface of the soil,
ON THE FOOD OF PLANTS.
The Food of Plants has for a long time excited an anxious enquiry, and a great variety of conjectures have been formed as to what it consists of, or in what state it is taken up by the Roots. It has been an object of research with men of the greatest talents and learning, and to aid them, the powers of chemistry have been exerted and applied in a variety of ingenious experiments. The earth, as well as vegetables and animals, has been analysed and variously described, and accurate observations have been made and stated; but as yet no one has been able to describe a theory that has obtained general concurrence, or to establish a clear and practical rule for ascertaining the quantity and quality of the Food of Plants furnished by particular soils, nor the means of giving fertility, or restoring it when exhausted, by regulated proportions.
Although the earth appears capable of affording and sustaining a spontaneous produce in vegetables and fruit, her powers of production or principles of fertility are found to be limited, and possessed in different degrees by different portions; and it has been clearly proved that they are sooner or later exhausted by the growth of particular vege
tables, according to the nature and situation of the soil; it therefore became an object essential to the Arts of Horticulture and Agriculture, to ascertain the nature of vegetables and the composition of the soil most congenial to their different productions, in order to be enabled to remedy defects, remove opposing matter, and supply deficiencies, or, in other words, to sustain, increase, or diminish, the powers of production, or princi. ples of fertility.
Vegetables, like animals, vary in their nature and habits, and like them have their peculiar food, for although the Food of Plants may generally be composed of the same elements, it varies in the proportion of its composition, and thereby becomes adapted to different purposes ; thus we find, that
a soil which will furnish only Food enough to support one Plant of a peculiar kind, will at the same time furnish sufficient to sustain many others of different species.
Bradley, in the work I have before noticed, says, “ Land animals may be likened in general to those Plants which are called Terrene, for that they live only upon the earth, such as oak, elm, beech, &c.; amphibious animals, such as otters, beavers, tortoises, frogs, &c. which live as well on the land as in the waters, may be compared to the willows, alders, minths, &c. The fish kind, or aquatic. race, whether of the rivers or the sea, are analogous to the water plants, such as water lilies, water plantains, &c. which live only in the fresh
waters, or the fuci, &c. which are sea or salt water plants, and not any of these will live out of its proper element; from whence we may conclude how improper it would be to plant a water lily on a dry sandy desert, or an oak at the bottom of the sea, which would be just as reasonable as if we propose to feed a dog with hay, or a horse with fish; however this rule of nature has been so little observed, even by some of our greatest planters, that we can hardly boast of good success in one out of five plantations that have been made.”
He also says, “ I shall beg leave to remark, that as the several land animals have their respective diets, so have the Terrene Plants their several soils from whence they derive their nourishment, as some animals feed on flesh, others on fish, &c. so do Plants love, some clay, others loam, sand or gravel; nor is this all we ought to observe, we must consider likewise how beneficial to every Plant is a right exposure, whether in a vale, the sides or tops of hills, exposed to the south or north winds, whether inland or near the sea, for it is a proper exposure that keeps a Plant in health.' Bradley, Hitt, and Miller, consider the
Food of Plants to be salts, which every species of earth, more or less, contains within itself; and that according to the proportion of salts contained in each kind of soil or manure, will its prolificacy be.
That all soils, and all vegetable and animal matter, may be found to produce salts, under certain chemical processes, I have no doubt; but this does