Peat and its Uses as Fertilizer and Fuel.

by Samuel William Johnson.

INTRODUCTION.

In the years 1857 and 1858, the writer, in the capacity of Chemist to the State Agricultural Society of Connecticut, was commissioned to make investigations into the agricultural uses of the deposits of peat or swamp muck which are abundant in this State; and, in 1858, he submitted a Report to Henry A. Dyer, Esq., Corresponding Secretary of the Society, embodying his conclusions. In the present work the valuable portions of that Report have been recast, and, with addition of much new matter, form Parts I. and II. The remainder of the book, relating to the preparation and employment of peat for fuel, &c., is now for the first time published, and is intended to give a faithful account of the results of the experience that has been acquired in Europe, during the last twenty-five years, in regard to the important subject of which it treats.

The employment of peat as an amendment and absorbent for agricultural purposes has proved to be of great advantage in New-England farming.

It is not to be doubted, that, as fuel, it will be even more valuable than as a fertilizer. Our peat-beds, while they do not occupy so much territory as to be an impediment and a reproach to our country, as they have been to Ireland, are yet so abundant and so widely distributed--occurring from the Atlantic to the Missouri, along and above the 40th parallel, and appearing on our Eastern Coast at least as far South as North Carolina[1]--as to present, at numberless points, material, which, sooner or later, will serve us most usefully when other fuel has become scarce and costly.

The high prices which coal and wood have commanded for several years back have directed attention to peat fuel; and, such is the adventurous character of American enterprise, it cannot be doubted that we shall rapidly develop and improve the machinery for producing it. As has always been the case, we shall waste a vast deal of time and money in contriving machines that violate every principle of mechanism and of economy; but the results of European invention furnish a safe basis from which to set out, and we have among us the genius and the patience that shall work out the perfect method.

It may well be urged that a good degree of caution is advisable in entering upon the peat enterprise. In this country we have exhaustless mines of the best coal, which can be afforded at a very low rate, with which other fuel must compete. In Germany, where the best methods of working peat have originated, fuel is more costly than here; and a universal and intense economy there prevails, of which we, as a people, have no conception.

If, as the Germans themselves admit, the peat question there is still a nice one as regards the test of dollars and cents, it is obvious, that, for a time, we must "hasten slowly." It is circ.u.mstances that make peat, and gold as well, remunerative or otherwise; and these must be well considered in each individual case. Peat is the name for a material that varies extremely in its quality, and this quality should be investigated carefully before going to work upon general deductions.

In my account of the various processes for working peat by machinery, such data as I have been able to find have been given as to cost of production. These data are however very imperfect, and not altogether trustworthy, in direct application to American conditions. The cheapness of labor in Europe is an item to our disadvantage in interpreting foreign estimates. I incline to the belief that this is more than offset among us by the quality of our labor, by the energy of our administration, by the efficiency of our overseeing, and, especially, by our greater skill in the adaptation of mechanical appliances. While counselling caution, I also recommend enterprise in developing our resources in this important particular; knowing full well, however, that what I can say in its favor will scarcely add to the impulse already apparent among my countrymen.

SAMUEL W. JOHNSON.

_Sheffield Scientific School_,} _Yale College, June, 1866._ }

FOOTNOTES:

[1] The great Dismal Swamp is a grand peat bog, and doubtless other of the swamps of the coast, as far south as Florida and the Gulf, are of the same character.

PART I.

THE ORIGIN, VARIETIES, AND CHEMICAL CHARACTERS OF PEAT.

1. _What is Peat?_

By the general term Peat, we understand the organic matter or vegetable soil of bogs, swamps, beaver-meadows and salt-marshes.

It consists of substances that have resulted from the decay of many generations of aquatic or marsh plants, as mosses, sedges, coa.r.s.e gra.s.ses, and a great variety of shrubs, mixed with more or less mineral substances, derived from these plants, or in many cases blown or washed in from the surrounding lands.

2. _The conditions under which Peat is formed._

In this country the production of Peat from fallen and decaying plants, depends upon the presence of so much water as to cover or saturate the vegetable matters, and thereby hinder the full access of air. Saturation with water also has the effect to maintain the decaying matters at a low temperature, and by these two causes in combination, the process of decay is made to proceed with great slowness, and the solid products of such slow decay, are compounds that themselves resist decay, and hence they acc.u.mulate.

In the United States there appears to be nothing like the extensive _moors_ or _heaths_, that abound in Ireland, Scotland, the north of England, North Germany, Holland, and the elevated plains of Bavaria, which are mostly level or gently sloping tracts of country, covered with peat or turf to a depth often of 20, and sometimes of 40, or more, feet.

In this country it is only in low places, where streams become obstructed and form swamps, or in bays and inlets on salt water, where the flow of the tide furnishes the requisite moisture, that our peat-beds occur. If we go north-east as far as Anticosti, Labrador, or Newfoundland, we find true moors. In these regions have been found a few localities of the _Heather_ (_Calluna vulgaris_), which is so conspicuous a plant on the moors of Europe, but which is wanting in the peat-beds of the United States.

In the countries above named, the weather is more uniform than here, the air is more moist, and the excessive heat of our summers is scarcely known. Such is the greater humidity of the atmosphere that the bog-mosses,--the so-called _Sphagnums_,--which have a wonderful avidity for moisture, (hence used for packing plants which require to be kept moist on journeys), are able to keep fresh and in growth during the entire summer. These mosses decay below, and throw out new vegetation above, and thus produce a bog, especially wherever the earth is springy.

It is in this way that in those countries, moors and peat-bogs actually grow, increasing in depth and area, from year to year, and raise themselves above the level of the surrounding country.

Prof. Marsh informs the writer that he has seen in Ireland, near the north-west coast, a granite hill, capped with a peat-bed, several feet in thickness. In the Bavarian highlands similar cases have been observed, in localities where the atmosphere and the ground are kept moist enough for the growth of moss by the extraordinary prevalence of fogs. Many of the European moors rise more or less above the level of their borders towards the centre, often to a height of 10 or 20 and sometimes of 30 feet. They are hence known in Germany as _high_ moors (_Hochmoore_) to distinguish from the level or dishing _meadow-moors_, (_Wiesenmoore_). The peat-producing vegetation of the former is chiefly moss and heather, of the latter coa.r.s.e gra.s.ses and sedges.

In Great Britain the reclamation of a moor is usually an expensive operation, for which not only much draining, but actual cutting out and burning of the compact peat is necessary.

The warmth of our summers and the dryness of our atmosphere prevent the acc.u.mulation of peat above the highest level of the standing water of our marshes, and so soon as the marshes are well drained, the peat ceases to form, and in most cases the swamp may be easily converted into good meadow land.

Springy hill-sides, which in cooler, moister climates would become moors, here dry up in summer to such an extent that no peat can be formed upon them.

As already observed, our peat is found in low places. In many instances its acc.u.mulation began by the obstruction of a stream. To that remarkable creature, the beaver, we owe many of our peat-bogs. These animals, from time immemorial, have built their dams across rivers so as to flood the adjacent forest. In the rich leaf-mold at the water's verge, and in the cool shade of the standing trees, has begun the growth of the sphagnums, sedges, and various purely aquatic plants. These in their annual decay have shortly filled the shallow borders of the stagnating water, and by slow encroachments, going on through many years, they have occupied the deeper portions, aided by the trees, which, perishing, give their fallen branches and trunks, towards completing the work. The trees decay and fall, and become entirely converted into peat; or, as not unfrequently happens, especially in case of resinous woods, preserve their form, and to some extent their soundness.

In a similar manner, ponds and lakes are encroached upon; or, if shallow, entirely filled up by peat deposits. In the Great Forest of Northern New York, the voyager has abundant opportunity to observe the formation of peat-swamps, both as a result of beaver dams, and of the filling of shallow ponds, or the narrowing of level river courses. The formation of peat in water of some depth greatly depends upon the growth of aquatic plants, other than those already mentioned. In our Eastern States the most conspicuous are the Arrow-head, (_Sagittaria_); the Pickerel Weed, (_Pontederia_;) Duck Meat, (_Lemna_;) Pond Weed, (_Potamogeton_;) various _Polygonums_, brothers of Buckwheat and Smart-weed; and especially the Pond Lilies, _(Nymphoea_ and _Nuphar_.) The latter grow in water four or five feet deep, their leaves and long stems are thick and fleshy, and their roots, which fill the oozy mud, are often several inches in diameter. Their decaying leaves and stems, and their huge roots, living or dead, acc.u.mulate below and gradually raise the bed of the pond. Their living foliage which often covers the water almost completely for acres, becomes a shelter or support for other more delicate aquatic plants and sphagnums, which, creeping out from the sh.o.r.e, may so develop as to form a floating carpet, whereon the leaves of the neighboring wood, and dust scattered by the wind collect, bearing down the ma.s.s, which again increases above, or is reproduced until the water is filled to its bottom with vegetable matter.

It is not rare to find in our bogs, patches of moss of considerable area concealing deep water with a treacherous appearance of solidity, as the hunter and botanist have often found to their cost. In countries of more humid atmosphere, they are more common and attain greater dimensions. In Zealand the surfaces of ponds are so frequently covered with floating beds of moss, often stout enough to bear a man, that they have there received a special name "_Hangesak_." In the Russian Ural, there occur lakes whose floating covers of moss often extend five or six feet above the water, and are so firm that roads are made across them, and forests of large fir-trees find support. These immense acc.u.mulations are in fact floating moors, consisting entirely of peat, save the living vegetation at the surface.

Sometimes these floating peat-beds, bearing trees, are separated by winds from their connection with the sh.o.r.e, and become swimming peat islands. In a small lake near Eisenach, in Central Germany, is a swimming island of this sort. Its diameter is 40 rods, and it consists of a felt-like ma.s.s of peat, three to five feet in depth, covered above by sphagnums and a great variety of aquatic plants. A few birches and dwarf firs grow in this peat, binding it together by their roots, and when the wind blows, they act as sails, so that the island is constantly moving about upon the lake.

On the Neusiedler lake, in Hungary, is said to float a peat island having an area of six square miles, and on lakes of the high Mexican Plateau are similar islands which, long ago, were converted in fruitful gardens.

3. _The different kinds of Peat._

Very great differences in the characters of the deposits in our peat-beds are observable. These differences are partly of color, some peats being gray, others red, others again black; the majority, when dry, possess a dark brown-red or snuff color. They also vary remarkably in weight and consistency. Some are compact, dest.i.tute of fibres or other traces of the vegetation from which they have been derived, and on drying, shrink greatly and yield tough dense ma.s.ses which burn readily, and make an excellent fuel. Others again are light and porous, and remain so on drying; these contain intermixed vegetable matter that is but little advanced in the peaty decomposition. Some peats are almost entirely free from mineral matters, and on burning, leave but a few _per cent._ of ash, others contain considerable quant.i.ties of lime or iron, in chemical combination, or of sand and clay that have been washed in from the hills adjoining the swamps. As has been observed, the peat of some swamps is mostly derived from mosses, that of others originates largely from gra.s.ses; some contain much decayed wood and leaves, others again are free from these.

In the same swamp we usually observe more or less of all these differences. We find the surface peat is light and full of partly decayed vegetation, while below, the deposits are more compact. We commonly can trace distinct strata or layers of peat, which are often very unlike each other in appearance and quality, and in some cases the light and compact layers alternate so that the former are found below the latter.

The light and porous kinds of peat appear in general to be formed in shallow swamps or on the surface of bogs, where there is considerable access of air to the decaying matters, while the compacter, older, riper peats are found at a depth, and seem to have been formed beneath the low water mark, in more complete exclusion of the atmosphere, and under a considerable degree of pressure.

The nature of the vegetation that flourishes in a bog, has much effect on the character of the peat. The peats chiefly derived from mosses that have grown in the full sunlight, have a yellowish-red color in their upper layers, which usually becomes darker as we go down, running through all shades of brown until at a considerable depth it is black.

Peats produced princ.i.p.ally from gra.s.ses are grayish in appearance at the surface, being full of silvery fibres--the skeletons of the blades of gra.s.ses and sedges, while below they are commonly black.

_Moss peat_ is more often fibrous in structure, and when dried forms somewhat elastic ma.s.ses. _Gra.s.s peat_, when taken a little below the surface, is commonly dest.i.tute of fibres; when wet, is earthy in its look, and dries to dense hard lumps.

Where mosses and gra.s.ses have grown together simultaneously in the same swamp, the peat is modified in its characters accordingly. Where, as may happen, gra.s.s succeeds moss, or moss succeeds gra.s.s, the different layers reveal their origin by their color and texture. At considerable depths, however, where the peat is very old, these differences nearly or entirely disappear.

The geological character of a country is not without influence on the kind of peat. It is only in regions where the rocks are granitic or silicious, where, at least, the surface waters are free or nearly free from lime, that _mosses_ make the bulk of the peat.

In limestone districts, peat is chiefly formed from _gra.s.ses_ and _sedges_.

This is due to the fact that mosses (sphagnums) need little lime for their growth, while the gra.s.ses require much; aquatic gra.s.ses cannot, therefore, thrive in pure waters, and in waters containing the requisite proportion of lime, gra.s.ses and sedges choke out the moss.

The accidental admixtures of soil often greatly affect the appearance and value of a peat, but on the whole it would appear that its quality is most influenced by the degree of decomposition it has been subjected to.

In meadows and marshes, overflowed by the ocean tides, we have _salt-peat_, formed from Sea-weeds (_Algae_,) Salt-wort (_Salicornia_,) and a great variety of marine or strand-plants. In its upper portions, salt-peat is coa.r.s.ely fibrous from the gra.s.s roots, and dark-brown in color. At sufficient depth it is black and dest.i.tute of fibres.

The fact that peat is fibrous in texture shows that it is of comparatively recent formation, or that the decomposition has been arrested before reaching its later stages. Fibrous peat is found near the surface, and as we dig down into a very deep bed we find almost invariably that the fibrous structure becomes less and less evident until at a certain depth it entirely disappears.

It is not depth simply, but age or advancement in decomposition, which determines these differences of texture.