[ CHAPTER XXI.]
THE MANAGEMENT OF MANURES.—Continued.
WHY DO WE FERMENT MANURE?
However much farmers may differ in regard to the advantages or disadvantages of fermenting manure, I have never met with one who contended that it was good, either in theory or practice, to leave manure for months, scattered over a barn-yard, exposed to the spring and autumn rains, and to the summer’s sun and wind. All admit that, if it is necessary to leave manure in the yards, it should be either thrown into a basin, or put into a pile or heap, where it will be compact, and not much exposed.
We did not need the experiments of Dr. Vœlcker to convince us that there was great waste in leaving manure exposed to the leaching action of our heavy rains. We did not know exactly how much we lost, but we knew it must be considerable. No one advocates the practice of exposing manure, and it is of no use to discuss the matter. All will admit that it is unwise and wasteful to allow manure to lie scattered and exposed over the barn-yards any longer than is absolutely necessary.
We should either draw it directly to the field and use it, or we should make it into a compact heap, where it will not receive more rain than is needed to keep it moist.
One reason for piling manure, therefore, is to preserve it from loss, until we wish to use it on the land.
“We all admit that,” said the Deacon, “but is there anything actually gained by fermenting it in the heap?”—In one sense, no; but in another, and very important sense, yes. When we cook corn-meal for our little pigs, we add nothing to it. We have no more meal after it is cooked than before. There are no more starch, or oil, or nitrogenous matters in the meal, but we think the pigs can digest the food more readily. And so, in fermenting manure, we add nothing to it; there is no more actual nitrogen, or phosphoric acid, or potash, or any other ingredient after fermentation than there was before, but these ingredients are rendered more soluble, and can be more rapidly taken up by the plants. In this sense, therefore, there is a great gain.
One thing is certain, we do not, in many cases, get anything like as much benefit from our manure as the ingredients it contains would lead us to expect.
Mr. Lawes, on his clayey soil at Rothamsted, England, has grown over thirty crops of wheat, year after year, on the same land. One plot has received 14 tons of barn-yard manure per acre every year, and yet the produce from this plot is no larger, and, in fact, is frequently much less, than from a few hundred pounds of artificial manure containing far less nitrogen.