Report of the Secretary of Agriculture for the Year 1860, p. 73-74 (1861)

Peat Ashes

Peat ashes, like all others, act mechanically, and improve sticky or tenacious clays by interposition. Peat, when dried and burned, or rather charred, would in some instances be a most valuable addition to lands, acting mechanically and chemically upon them, the charred vegetable matter changing the temperature of light colored lands by merely changing the color, and destroying the adhesiveness of clays by the arenaceous property of the charred peat. The charcoal would be a collector of gases, such as ammonia, and thus prove a permanent meliorator of the soils, but more especially of stiff clays.

*Transactions of the Highland Society.

Burning peat for its ashes has been prosecuted as a regular business in Holland, whence they are exported to Great Britain and to Belgium. The consideration in which they an1 held in the last mentioned country is due to the quantity of phosphate and sulphate of lime which they contain. According to Sprengel, 3,000 pounds of the best quality of peat ashes from Holland contain 300 pounds of sulphate of lime (gypsum) and 120 pounds of phosphate of lime. This explains their action upon clover and other forage crops. Mr. Mitchell,* in speaking of their use, says: "As a top dressing, these ashes are superior to common manure, it having been found in Flanders that the crops of clover, where the ashes were used, were much earlier, heavier and superior in every respect to those which have undergone a dressing of horse and cow-dung. As a top-dressing to the second crop of clover, they will be found highly advantageous. One of the best proofs of their usefulness is the fact, that while we have frequently in this country very backward and light crops of clover-grass, in Flanders, where this top-dressing is used, such a defection seldom or never occurs."

Sir John Sinclair quotes the declaration of eighty-three practical farmers that "they know by experience when clover is not manured with peat ashes to the amount of nineteen bushels to the acre, the following crop is very bad, notwithstanding any culture that can be given to the soil; whereas they always have an excellent crop of wheat after clover, and doubtless in proportion to the quantity of the above manure used."

In the counties of Newberg, Berks and Hampshire, peat ashes are in high repute as a dressing for clovers, sainfoin, rye, grasses and rape, which is natural, as the ashes used contain the phosphate and sulphate of lime, and also some potash. Wherever manures are used upon the turnip crop, whether mineral or organic, if they contain phosphate of lime, they will be found of great advantage. It is to be regretted that the scientific annals of our country are not rich in the analyses of our peat ashes, or those of our coals, since it is believed when the methods now known for detecting and dosing phosphoric acid, a greater value will be attached to our peats as fertilizers, particularly on account of the phosphoric acid they all doubtless contain in greater or less proportion.

The effect which the writer has observed to follow the application of peat on his own land induces the belief that their action is more than is represented by the mechanical agency, or that which is due to their absorbing faculty. Peat ashes are said to be of great and particular service to crops of sainfoin; and such efficiency to that particular crop might have been expected a priori, since calcareous fertilizers are essential to its growth, the plant scarcely thriving at all on other than calcareous soils. Professor Johnston has found as high as six and a half per cent, of phosphate of lime in a peat taken from the Island of Lewis.

As a top-dressing for oats Mr. Gardner, of Paisley, obtained the following results from peat ashes:

Produce of grain per acre.

  qr. bu. p.
No manure 6 3 0
African guano, 2 cwt 6 7 2
Peruvian guano, 2 cwt 7 6 3
Peat ashes, 80 bushels 7 1 2

Mr. Gardner remarks: "The peat ashes were made from burning flow moss in the open air, with the fire kept closely covered in. They were about ten days later of being put on the oats than the other dressings, and it continued dry weather for some time after they were put on, and prevented them from having the effect they would have had, had they been put on earlier in the season. However, from their known composition they are a most valuable dressing, and will, no doubt, add greatly to the fertility of most soils, and are particularly worthy of notice from the ease with which they can be produced, in almost any quantity, in every county in Scotland." According to the analysis of Professor Johnston, the peat ashes employed in the above trial contained 3 per cent, of organic matter and 21 per cent, of gypsum.

The application of peat ashes cannot be economically made without a previous knowledge of their constituents; and that knowledge will enable the farmer to judge of the manner they should be applied and their quantity. Like all mineral manures, their action is continuous for a long time; and, according to Sprengel, "a good dressing will last for five or six years." Their duration, however, is dependent upon their composition, as well as the activity they may impart to different vegetations.

Peats yield ashes of qualities differing according to the positions from with they are taken. Those from the top of the bed, after removing the surface, are considered less valuable than those from the bottom layer, the top being more fibrous and less compact than the bottom, which, when dry, often presents an entirely different appearance from the turfs ordinarily used for fuel.

When it is designed to consume the peat entirely, leaving no vegetable matter, it should be well dried, and may then be burned in contact with the air, either in conical heaps, in furnaces, or in kilns made for the purpose. But where the object is two-fold, or where the charring of the peat is the desired result, a process similar to that employed for charring wood may be employed. But the charring of peat will be attended with much greater difficulty, as the organic fibers are much more divided and difficult to extinguish, partaking more or less of the properties of pyrophorus.

Thus, according to the inclinations of the operator, the peat may be burned, leaving a pure ash free from coal, or a mixture of ash in any proportion contained or that is practicable or compatible with the method employed in the operation. Charred peat acts mechanically or chemically according to the composition of the ash, as a disinfectant, or as an absorbent.