That which directly affects agriculture, as treated of in this book, is the value of this substance as a fertilizer. The manure of man consists (as is the case with that of other animals) of those parts of his food which are not retained in the increase of his body. If he be growing, his manure is poorer, as in the case of the ox, and it is subject to all the other modifications named in the early part of this chapter. His food is usually of a varied character, and is rich in nitrogen, the phosphates, and other inorganic constituents; consequently, his manure is made valuable by containing large quantities of these matters. As is the case with the ox, the dung contains the undigested food, the secretions (or leakings) of the digestive organs, and the insoluble parts of the ash of the digested food. The urine, in like manner, contains a large proportion of the nitrogen and the soluble inorganic parts of the digested food. When we consider how much richer the food of man is than that of horned cattle, we shall see the superior value of his excrement.
Night soil has been used as a manure, for ages, in China, which is, undoubtedly, one great secret of their success in supporting a dense population, for so long a time, without impoverishing the soil. It has been found, in many instances, to increase the productive power of the natural soil three-fold. That is, if a soil would produce ten bushels of wheat per acre, without manure, it would produce thirty bushels if manured with night soil.
Some have supposed that manuring with night soil would give disagreeable properties to plants: such is not the case; their quality is invariably improved. The color and odor of the rose become richer and more delicate by the use of the most offensive night soil as manure.
What is the direct object of plants?
What would result if this were not the case?
How may night soil be easily prepared for use, and its offensive odor prevented?
It is evident that this is the case from the fact that plants have it for their direct object to make over and put together the refuse organic matter, and the gases and the minerals found in nature, for the use of animals. If there were no natural means of rendering the excrement of animals available to plants, the earth must soon be shorn of its fertility, as the elements of growth when once consumed would be essentially destroyed, and no soil could survive the exhaustion. There is no reason why the manure of man should be rejected by vegetation more than that of any other animal; and indeed it is not, for ample experience has proved that for most soils there is no better manure in existence.
A single experiment will suffice to show that night soil may be so kept that there shall be no loss of its valuable gases, and consequently no offensive odor arising from it, while it may be removed and applied to crops without unpleasantness. All that is necessary to effect this wonderful change in night soil, and to turn it from its disagreeable character to one entirely inoffensive, is to mix with it a little charcoal dust, prepared muck, or any other good absorbent—thus making what is called poudrette. The mode of doing this must depend on circumstances. In many cases, it would be expedient to keep a barrel of the absorbent in the privy and throw down a small quantity every day. The effect on the odor of the house would amply repay the trouble.
Should pure night soil be used as a manure?
What precaution is necessary in preparing hog manure for use?