The idea to the contrary originated from not spreading the manure evenly. “But why ferment the manure at all? Why not draw it out fresh from the yards? Does fermentation increase the amount of plant-food in the manure?”--No. But it renders the plant-food in the manure more immediately available. It makes it more soluble. We ferment manure for the same reason that we decompose bone-dust or mineral phosphates with sulphuric acid, and convert them into superphosphate, or for the same reason that we grind our corn and cook the meal. These processes add nothing to the amount of plant-food in the bones or the nutriment in the corn. They only increase its availability. So in fermenting manure. When the liquid and solid excrements from well-fed animals, with the straw necessary to absorb the liquid, are placed in a heap, fermentation sets in and soon effects very important changes in the nature and composition of the materials. The insoluble woody fibre of the straw is decomposed and converted into humic and ulmic acids. These are insoluble; and when manure consists almost wholly of straw or corn stalks, there would be little gained by fermenting it. But when there is a good proportion of manure from well fed animals in the heap, carbonate of ammonia is formed from the nitrogenous compounds in the manure, and this ammonia unites with the humic and ulmic acids and forms humate and ulmate of ammonia. These ammoniacal salts are soluble in water--as the brown color of the drainings of a manure heap sufficiently indicates. Properly fermented manure, therefore, of good quality, is a much more active and immediately useful fertilizer than fresh, unfermented manure. There need be no loss of ammonia from evaporation, and the manure is far less bulky, and costs far less labor to draw out and spread. The only loss that is likely to occur is from leaching, and this must be specially guarded against. 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.