THEORY OF MANURE.Itis very well known that a young orchard will not, usually, flourish on the site of an old one; for the older trees are supposed to have withdrawn from the soil certain elements necessary to their growth; and as necessary to the growth of the young tree, should it be planted there. There is no “like” or “dislike” of the soil to the tree; it is a plain case of starvation. The tree needs, and the soil cannot supply certain elements of its wood.But if, after a plant has abstracted from the soil certain ingredients, the whole plant is decomposed and returned to the earth, the soil repossesses itself of the lost elements, and is ready to yield them up again to a plant of the same kind. If the straw of wheat be burned upon the field, annually, the soil would yield fine crops for a thousand successive years, that is so far as thestraw is concerned. But if the grain is removed, and nothing resupplies the drain of phosphates which it makes from the soil, the soil will in due time, according to the original quantities in the soil, cease to yieldgrain, although the straw may be admirable. But if both straw and kernel were every year burned upon thefield, as grass and its seed is upon the prairies, wheat would grow for a thousand years in succession. The same is true of corn, of potatoes, and of any annual crop. When the annual growth is restored to the soil, it is repossessed of all its treasure which had been loaned for a season. If a part of the crop is removed, the soil is poorer by just so much as the portion removed contained within it of the elements necessary to that crop, and it must be restored artificially,i. e. by manuring; or by allowing the earth to prepare (by disintegration or decomposition of its minerals) a new supply;i. e. by fallowing. A forest will grow for ages on the same spot, for it returns annually its leaves, and, gradually, by force of accidents and the elements, its twigs, branches, trunks, etc., to the soil again. But let the whole product be gradually removed, and the soil would soon be unable to supply the trees their nourishment, except in cases where the soil was very rich in the materials of growth. The forests of Germany, like our mines, are under the management of the government. It was customary, for a time, to allow the peasants the use of thetwigsandsmaller branches; but analysis has shown that in these, especially, resides the large proportion of potash entering into the composition of trees; the annual removal of it debilitated the trees to an extent that obliged the Conservators to change their mode of proceeding.On the other hand, in one of Mr. Horsford’s letters from Germany, we have the question of growing plants upon their own ashes, brought, by the ablest chemist of the age, directly to the test of experiment.“In the spring preceding my arrival in Giessen, Professor Liebig planted some grape scions under the windows of the laboratory. He fed them, if I may use such an expression, upon the ashes of the grape vine—or upon the proper inorganic food of the grape, as shown by analyses of its ashes. The growth has been enormous, and several of the vines bore large clusters of grapes in the course of the season.Indeed, I know not but all, as my attention was drawn to them particularly only since the fruit has been gathered. The soil otherwise is little better than a pavement—a kind of fine gravel, in which scarcely anything takes root.“I was shown pots of wheat, in different stages of their growth, that had been fed variously—some upon the inorganic matters they needed, according to the analyses of their ashes—others had merely shared the tribute of the general soil. The results in numbers I don’t yet know. In appearance, no one could be at a loss to judge of what might be expected.”The fact that depopulated forest-grounds change the character of their growth, is quite familiar to all; and the reasons of it have been variously debated.
Itis very well known that a young orchard will not, usually, flourish on the site of an old one; for the older trees are supposed to have withdrawn from the soil certain elements necessary to their growth; and as necessary to the growth of the young tree, should it be planted there. There is no “like” or “dislike” of the soil to the tree; it is a plain case of starvation. The tree needs, and the soil cannot supply certain elements of its wood.
But if, after a plant has abstracted from the soil certain ingredients, the whole plant is decomposed and returned to the earth, the soil repossesses itself of the lost elements, and is ready to yield them up again to a plant of the same kind. If the straw of wheat be burned upon the field, annually, the soil would yield fine crops for a thousand successive years, that is so far as thestraw is concerned. But if the grain is removed, and nothing resupplies the drain of phosphates which it makes from the soil, the soil will in due time, according to the original quantities in the soil, cease to yieldgrain, although the straw may be admirable. But if both straw and kernel were every year burned upon thefield, as grass and its seed is upon the prairies, wheat would grow for a thousand years in succession. The same is true of corn, of potatoes, and of any annual crop. When the annual growth is restored to the soil, it is repossessed of all its treasure which had been loaned for a season. If a part of the crop is removed, the soil is poorer by just so much as the portion removed contained within it of the elements necessary to that crop, and it must be restored artificially,i. e. by manuring; or by allowing the earth to prepare (by disintegration or decomposition of its minerals) a new supply;i. e. by fallowing. A forest will grow for ages on the same spot, for it returns annually its leaves, and, gradually, by force of accidents and the elements, its twigs, branches, trunks, etc., to the soil again. But let the whole product be gradually removed, and the soil would soon be unable to supply the trees their nourishment, except in cases where the soil was very rich in the materials of growth. The forests of Germany, like our mines, are under the management of the government. It was customary, for a time, to allow the peasants the use of thetwigsandsmaller branches; but analysis has shown that in these, especially, resides the large proportion of potash entering into the composition of trees; the annual removal of it debilitated the trees to an extent that obliged the Conservators to change their mode of proceeding.
On the other hand, in one of Mr. Horsford’s letters from Germany, we have the question of growing plants upon their own ashes, brought, by the ablest chemist of the age, directly to the test of experiment.
“In the spring preceding my arrival in Giessen, Professor Liebig planted some grape scions under the windows of the laboratory. He fed them, if I may use such an expression, upon the ashes of the grape vine—or upon the proper inorganic food of the grape, as shown by analyses of its ashes. The growth has been enormous, and several of the vines bore large clusters of grapes in the course of the season.Indeed, I know not but all, as my attention was drawn to them particularly only since the fruit has been gathered. The soil otherwise is little better than a pavement—a kind of fine gravel, in which scarcely anything takes root.
“I was shown pots of wheat, in different stages of their growth, that had been fed variously—some upon the inorganic matters they needed, according to the analyses of their ashes—others had merely shared the tribute of the general soil. The results in numbers I don’t yet know. In appearance, no one could be at a loss to judge of what might be expected.”
The fact that depopulated forest-grounds change the character of their growth, is quite familiar to all; and the reasons of it have been variously debated.