Peat and its Uses as Fertilizer and Fuel

by Samuel W. Johnson

Substances soluble in water, etc.	No. 1,
	Without	No. 2,	No. 3,
	Artificial	Common	Air and
	Supply of	Air	Carbonic
	Air.	Added.	acid added.
Mineral matters	2.04	3.71	4.99
Potash	0.07	0.17	0.14
Soda	0.17	0.23	0.28
Organic matters	2.76	4.32	2.43
Weight of Crops	5.89	10.49	12.35

It will be seen from the above that air alone exercised nearly as much solvent effect as the mixture of air with one-fourth its weight of carbonic acid; this is doubtless, in part due to the fact that the air, upon entering the soil rich in humus, caused the abundant formation of carbonic acid, as will be presently shown must have been the case. It is, however, probable that organic acids (crenic and apocrenic,) and nitric acid were also produced (by oxidation,) and shared with carbonic the work of solution.

It is almost certain, that the acids of peat exert a powerful decomposing, and ultimately solvent effect on the minerals of the soil; but on this point we have no precise information, and must therefore be content merely to present the probability. This is sustained by the fact that the crenic, apocrenic and humic acids, though often partly uncombined, are never wholly so, but usually occur united in part to various bases, viz.: lime, magnesia, ammonia, potash, alumina and oxide of iron.

The crenic and apocrenic acids (that are formed by the oxidation of ulmic and humic acids,) have such decided acid characters,—crenic acid especially, which has a strongly sour taste—that we cannot well doubt their dissolving action.

IV.—The influence of peat on the temperature of light soils dressed with it may often be of considerable practical importance. A light dry soil is subject to great variations of temperature, and rapidly follows the changes of the atmosphere from cold to hot, and from hot to cold. In the summer noon a sandy soil becomes so warm as to be hardly endurable to the feel, and again it is on such soils that the earliest frosts take effect. If a soil thus subject to extremes of temperature have a dressing of peat, it will on the one hand not become so warm in the hot day, and on the other hand it will not cool so rapidly, nor so much in the night; its temperature will be rendered more uniform, and on the whole, more conducive to the welfare of vegetation. This regulative effect on temperature is partly due to the stores of water held by peat. In a hot day this water is constantly evaporating, and this, as all know, is a cooling process. At night the peat absorbs vapor of water from the air, and condenses it within its pores, this condensation is again accompanied with the evolution of heat.

It appears to be a general, though not invariable fact, that dark colored soils, other things being equal, are constantly the warmest, or at any rate maintain the temperature most favorable to vegetation. It has been repeatedly observed that on light-colored soils plants mature more rapidly, if the earth be thinly covered with a coating of some black substance. Thus Lampadius, Professor in the School of Mines at Freiberg, a town situated in a mountainous part of Saxony, found that he could ripen melons, even in the coolest summers, by strewing a coating of coal-dust an inch deep over the surface of the soil. In some of the vineyards of the Rhine, the powder of a black slate is employed to hasten the ripening of the grape.

Girardin, an eminent French agriculturist, in a series of experiments on the cultivation of potatoes, found that the time of their ripening varied eight to fourteen days, according to the character of the soil. He found, on the 25th of August, in a very dark soil, made so by the presence of much humus or decaying vegetable matter, twenty-six varieties ripe; in sandy soil but twenty, in clay nineteen, and in a white lime soil only sixteen.

It cannot be doubted then, that the effect of dressing a light sandy or gravelly soil with peat, or otherwise enriching it in vegetable matter, is to render it warmer, in the sense in which that word is usually applied to soils. The upward range of the thermometer is not, indeed, increased, but the uniform warmth so salutary to our most valued crops is thereby secured.

In the light soils stable-manure wastes too rapidly because, for one reason, at the extremes of high temperature, oxidation and decay proceed with great rapidity, and the volatile portions of the fertilizer are used up faster than the plant can appropriate them, so that not only are they wasted during the early periods of growth, but they are wanting at a later period when their absence may prove the failure of a crop.

B. The ingredients and qualities which make peat a direct fertilizer next come under discussion. We shall notice: