Peat and its Uses as Fertilizer and Fuel

by Samuel W. Johnson

When peat has once become air-dry, it no longer manifests this avidity for water. In drying it shrinks, loses its porosity and requires long soaking to saturate it again. In the soil, however, it rarely becomes air-dry, unless indeed, this may happen during long drouth with a peaty soil, such as results from the draining of a bog.

II.—Absorbent power for ammonia.

All soils that deserve to be called fertile, have the property of absorbing and retaining ammonia and the volatile matters which escape from fermenting manures, but light and coarse soils may be deficient in this power. Here again in respect to its absorptive power for ammonia, peat comes to our aid.

It is easy to show by direct experiment that peat absorbs and combines with ammonia.

In 1858 I took a weighed quantity of air-dry peat from the New Haven Beaver Pond, (a specimen furnished me by Chauncey Goodyear, Esq.,) and poured upon it a known quantity of dilute solution of ammonia, and agitated the two together occasionally during 48 hours. I then distilled off at a boiling heat the unabsorbed ammonia and determined its quantity. This amount subtracted from that of the ammonia originally employed, gave the quantity of ammonia absorbed and retained by the peat at the temperature of boiling water.

The peat retained ammonia to the amount of 0.95 of one per cent.

I made another trial at the same time with carbonate of ammonia, adding excess of solution of this salt to a quantity of peat, and exposing it to the heat of boiling water, until no smell of ammonia was perceptible. The entire nitrogen in the peat was then determined, and it was found that the dry peat which originally contained nitrogen equivalent to 2.4 per cent. of ammonia, now yielded an amount corresponding to 3.7 per cent. The quantity of ammonia absorbed and retained at a temperature of 212°, was thus 1.3 per cent.

This last experiment most nearly represents the true power of absorption; because, in fermenting manures, ammonia mostly occurs in the form of carbonate, and this is more largely retained than free ammonia, on account of its power of decomposing the humate of lime, forming with it carbonate of lime and humate of ammonia.

The absorbent power of peat is well shown by the analyses of three specimens, sent me in 1858, by Edwin Hoyt, Esq., of New Canaan, Conn. The first of these was the swamp muck he employed. It contained in the air-dry state nitrogen equivalent to 0.58 per cent. of ammonia. The second sample was the same muck that had lain under the flooring of the horse stables, and had been, in this way, partially saturated with urine. It contained nitrogen equivalent to 1.15 per cent. of ammonia. The third sample was, finally, the same muck composted with white-fish. It contained nitrogen corresponding to 1.31 per cent. of ammonia.[3]

The quantities of ammonia thus absorbed, both in the laboratory and field experiments are small—from 0.7 to 1.3 per cent. The absorption is without doubt chiefly due to the organic matter of the peats, and in all the specimens on which these trials were made, the proportion of inorganic matter is large. The results therefore become a better expression of the power of peat, in general, to absorb ammonia, if we reckon them on the organic matter alone. Calculated in this way, the organic matter of the Beaver Pond peat (which constitutes but 68 per cent. of the dry peat) absorbs 1.4 per cent. of free ammonia, and 1.9 per cent. of ammonia out of the carbonate of ammonia.