Peat and its Uses as Fertilizer and Fuel Part 4

PROPORTIONS OF NITROGEN, ETC., IN PEAT.

---------+-------------+------------+------------+---------+------------ Total Ammonia, a.n.a.lyst. Nitrogen. per cent. Nitric acid.

---------+-------------+------------+------------+---------+------------ 1--Brown Peat Air dry (?) Boussingault 2.20 0.018 0.000 2--Black Peat " " Undetermined 0.025 Undetermined 3--Peat Dried at 212 Reichardt[4] " 0.152 0.483 4--Peat " " " 0.165 0.525 5--Peat " " " 0.305 0.241 6--Peat " " " 0.335 0.421 ---------+-------------+------------+------------+---------+------------

Specimens 3, 4 and 5, are swamp (or heath) mucks, and have been weathered for use in flower-culture. 3 and 4 are alike, save that 3 has been weathered a year longer than 4. They contain respectively 41, 56 and 67 _per cent._ of organic matter.

Sample 6, containing 86 _per cent._ of organic matter, is employed as a manure with great advantage, and probably was weathered before a.n.a.lysis.

It contained 85 _per cent._ of organic substance.

More important to us than the circ.u.mstance that this peat contains but little or no ammonia or nitric acid, and the other contains such or such a fraction of one _per cent._ of these bodies, is the grand fact that all peats may yield a good share of their nitrogen to the support of crops, when properly treated and applied.

Under the influence of Liebig's teachings, which were logically based upon the best data at the disposal of this distinguished philosopher when he wrote 25 years ago, it has been believed that the nitrogen of a fertilizer, in order to be available, must be converted into ammonia and presented in that shape to the plant. It has been recently made clear that nitric acid, rather than ammonia, is the form of nitrogenous food which is most serviceable to vegetation, and the one which is most abundantly supplied by the air and soil. The value of ammonia is however positive, and not to be overlooked.

When peat, properly prepared by weathering or composting, is suitably incorporated with a poor or light soil, it slowly suffers decomposition and wastes away. If it be wet, and air have access in limited quant.i.ty, especially if _lime_ be mixed with it, a portion of its nitrogen is gradually converted into ammonia. With full access of air _nitric acid_ is produced. In either case, it appears that a considerable share of the nitrogen escapes in the free state as gas, thereby becoming useless to vegetation until it shall have become converted again into ammonia or nitric acid. It happens in a cultivated soil that the oxygen of the air is in excess at the surface, and less abundant as we go down until we get below organic matters: it happens that one day it is saturated with water more or less, and another day it is dry, so that at one time we have the conditions for the formation of ammonia, and at another, those favorable to producing nitric acid. In this way, so far as our present knowledge warrants us to affirm, organic matters, decaying in the soil, continuously yield portions of their nitrogen in the forms of ammonia and nitric acid for the nourishment of plants.

The farmer who skillfully employs as a fertilizer a peat containing a good proportion of nitrogen, may thus expect to get from it results similar to what would come from the corresponding quant.i.ty of nitrogen in guano or stable manure.

But the capacity of peat for feeding crops with, nitrogen appears not to stop here. Under certain conditions, _the free nitrogen of the air which cannot be directly appropriated by vegetation, is oxidized in the pores of the soil to nitric acid, and thus, free of expense to the farmer, his crops are daily dressed with the most precious of all fertilizers_.

This gathering of useless nitrogen from the air, and making it over into plant-food cannot go on in a soil dest.i.tute of organic matter, requires in fact that vegetable remains or humified substances of some sort be present there. The evidence of this statement, whose truth was maintained years ago as a matter of opinion by many of the older chemists, has recently become nearly a matter of demonstration by the investigations of Boussingault and Knop, while the explanation of it is furnished by the researches of Schoenbein and Zabelin. To attempt any elucidation of it here would require more s.p.a.ce than is at our disposal.

It is plain from the contents of this paragraph that peat or swamp muck is, in general, an abundant source of nitrogen, and is often therefore an extremely cheap means of replacing the most rare and costly fertilizers.

II.--With regard to the _inorganic matters of peat_ considered as food to plants, it is obvious, that, leaving out of the account for the present, some exceptional cases, they are useful as far as they go.

In the ashes of peats, we almost always find small quant.i.ties of sulphate of lime, magnesia and phosphoric acid. Potash and soda too, are often present, though rarely to any considerable amount. Carbonate and sulphate of lime are large ingredients of the ashes of about one-half, of the thirty-three peats and swamp mucks I have examined. The ashes of the other half are largely mixed with sand and soil, but in most cases also contain considerable sulphate of lime, and often carbonates of lime and magnesia.

In one swamp-muck, from Milford, Conn., there was found but two _per cent._ of ash, at least one-half of which was sand, and the remainder sulphate of lime, (gypsum.) In other samples 20, 30, 50 and even 60 _per cent._ remained after burning off the organic matter. In these cases the ash is chiefly sand. The amount of ash found in those peats which were most free from sand, ranges from five to nine _per cent._ Probably the average proportion of true ash, viz.: that derived from the organic matters themselves, not including sand and accidental ingredients, is not far from five _per cent._

In twenty-two specimens of European peat, examined by Websky, Jaeckel, Walz, Wiegmann, Einhof and Berthier, eleven contained from 0.6 to 3.5 _per cent._ of ash. The other eleven yielded from 5.3 to 22 _per cent._ The average of the former was 2.4, that of the latter 12.7 _per cent._ Most of these contained a considerable proportion of sand or soil.

Variation in the composition as well as in the quant.i.ty of ash is very great.

Three a.n.a.lyses of peat-ashes have been executed at the author's instance with the subjoined results:

a.n.a.lYSES OF PEAT-ASHES.

---------------------------+-----------+-----------+---------- A. B. C.

Potash. 0.69 0.80 3.46 Soda. 0.58 trace.

Lime. 40.52 35.59 6.60 Magnesia. 6.06 4.92 1.05 Oxide of iron and alumina. 5.17 9.08 15.59 Phosphoric acid. 0.50 0.77 1.55 Sulphuric acid. 5.52 10.41 4.04 Chlorine. 0.15 0.43 0.70 Soluble silica. 8.23 1.40 } Carbonic acid. 19.60 22.28 } 67.01 Sand. 12.11 15.04 } +-----------+-----------+---------- 99.13 100.74 100.00 ---------------------------+-----------+-----------+----------

A was furnished by Mr. Daniel Buck, Jr., of Poquonock, Conn., and comes from a peat which he uses as fuel.

B was sent by Mr. J. H. Stanwood, of Colebrook, Conn.

C was sent from Guilford, Conn., by Mr. Andrew Foote.[5]

A and B, after excluding sand, are seen to consist chiefly of carbonates and sulphates of lime and magnesia. III. contains a very large proportion of sand and soluble silica, much iron and alumina, less lime and sulphuric acid. Potash and phosphoric acid are three times more abundant in C than in the others.

Instead of citing in full the results of Websky, Jaeckel and others, it will serve our object better to present the maximum, minimum and average proportions of the important ingredients in twenty-six recent a.n.a.lyses, (including these three,) that have come under the author's notice.

VARIATIONS AND AVERAGES IN COMPOSITION OF PEAT-ASHES.

_Minimum._ _Maximum._ _Average._ Potash 0.05 to 3.64 0.89 per cent.

Soda none " 5.73 0.83 "

Lime 4.72 " 58.38 24.00 "

Magnesia none " 24.39 3.20 "

Alumina 0.90 " 20.50 5.78 "

Oxide of iron none " 73.33 18.70 "

Sulphuric acid none " 37.40 7.50 "

Chlorine " " 6.50 0.60 "

Phosphoric acid " " 6.29 2.56 "

Sand 0.99 " 56.97 25.50 "

It is seen from the above figures that the ash of peat varies in composition to an indefinite degree. Lime is the only ingredient that is never quite wanting, and with the exception of sand, it is on the average the largest. Of the other agriculturally valuable components, sulphuric acid has the highest average; then follows magnesia; then phosphoric acid, and lastly, potash and soda: all of these, however, may be nearly or quite lacking.

Websky, who has recently made a study of the composition of a number of German peats, believes himself warranted to conclude that peat is so modified in appearance by its mineral matters, that the quant.i.ty or character of the latter may be judged of in many cases by the eye. He remarks, (_Journal fuer Praktische Chemie, Bd. 92, S. 87_,) "that while for example the peats containing much sand and clay have a red-brown powdery appearance, and never a.s.sume a l.u.s.trous surface by pressure; those which are very rich in lime, are black, sticky when moist, hard and of a waxy l.u.s.ter on a pressed surface, when dry: a property which they share indeed with very dense peats that contain little ash. Peats impregnated with iron are easily recognized. Their peculiar odor, and their changed appearance distinguish them from all others."

From my own investigations on thirty specimens of Connecticut peats, I am forced to disagree with Websky entirely, and to a.s.sert that except as regards sand, which may often be detected by the eye, there is no connection whatever between the quant.i.ty or character of the ash and the color, consistency, density or any other external quality of the peat.

The causes of this variation in the ash-content of peat, deserve a moment's notice. The plants that produce peat contain considerable proportions of lime, magnesia, alkalies, sulphuric acid, chlorine and phosphoric acid, as seen from the following a.n.a.lysis by Websky.

COMPOSITION OF THE ASH OF SPHAGNUM.

Potash. 17.2 Soda. 8.3 Lime. 11.8 Magnesia. 6.7 Sulphuric acid. 6.5 Chlorine. 6.2 Phosphoric acid. 6.7 _Per cent._ of ash, 2.5.

The mineral matters of the sphagnum do not all become ingredients of the peat; but, as rapidly as the moss decays below, its soluble matters are to a great degree absorbed by the vegetation, which is still living and growing above. Again, when a stream flows through a peat-bed, soluble matters are carried away by the water, which is often dark-brown from the substances dissolved in it. Finally the soil of the adjacent land is washed or blown upon the swamp, in greater or less quant.i.ties.

III.--_The decomposition of peat in the soil offers some peculiarities_ that are worthy of notice in this place. Peat is more gradual and regular in decay than the vegetable matters of stable dung, or than that furnished by turning under sod or green crops. It is thus a more steady and lasting benefit, especially in light soils, out of which ordinary vegetable manures disappear too rapidly. The decay of peat appears to proceed through a regular series of steps. In the soil, especially in contact with soluble alkaline bodies, as ammonia and lime, there is a progressive conversion of the _insoluble_ or _less soluble_ into _soluble_ compounds. Thus the inert matters that resist the immediate solvent power of alkalies, absorb oxygen from the air, and form the humic or ulmic acids soluble in alkalies; the humic acids undergo conversion into crenic acid, and this body, by oxidation, pa.s.ses into apocrenic acid. The two latter are soluble in water, and, in the porous soil, they are rapidly brought to the end-results of decay, viz.: water, carbonic acid, ammonia and free nitrogen.

Great differences must be observed, however, in the rapidity with which these changes take place. Doubtless they go on most slowly in case of the fibrous compact peats, and perhaps some of the lighter and more porous samples of swamp muck, would decay nearly as fast as rotted stable dung.

It might appear from the above statement, that the effect of exposing peat to the air, as is done when it is incorporated with the soil, would be to increase relatively the amount of soluble organic matters; but the truth is, that they are often actually diminished. In fact, the oxidation and consequent removal of these soluble matters (crenic and apocrenic acids,) is likely to proceed more rapidly than they can be produced from the less soluble humic acid of the peat.

IV.--_Comparison of Peat with Stable Manure._

The fertilizing value of peat is best understood by comparing it with some standard manure. Stable manure is obviously that fertilizer whose effects are most universally observed and appreciated, and by setting a.n.a.lyses of the two side by side, we may see at a glance, what are the excellencies and what the deficiencies of peat. In order rightly to estimate the worth of those ingredients which occur in but small proportion in peat, we must remember that it, like stable manure, may be, and usually should be, applied in large doses, so that in fact the smallest ingredients come upon an acre in considerable quant.i.ty. In making our comparison, we will take the a.n.a.lysis of Peat from the farm of Mr. Daniel Buck, Jr., of Poquonock, Conn., and the average of several a.n.a.lyses of rotted stable dung of _good quality_.

No. _I_, is the a.n.a.lysis of Peat; No. _II_, that of well rotted stable manure:--

_I._ _II._ Water expelled at 212 degrees. 79.000 79.00 {Soluble in dilute solution } Org. { of carbonate of soda. 7.312 } Matter. {Insoluble in solution } 14.16 { of carbonate of soda. 12.210 } Potash. 0.010 0.65 Soda. 0.009 Lime. 0.608 0.57 Magnesia. 0.091 0.19 Phosphoric acid. 0.008 0.23 Sulphuric acid. 0.082 0.27 Nitrogen. 0.600 0.55 Matters, soluble in water. 0.450 4.42

To make the comparison as just as possible, the peat is calculated with the same content of water, that stable dung usually has.

We observe then, that the peat contains in a given quant.i.ty, _about one-third more organic matter, an equal amount of lime and nitrogen_; but is _deficient in potash, magnesia, phosphoric and sulphuric acids_.

The deficiencies of this peat in the matter of composition may be corrected, as regards potash, by adding to 100 lbs. of it 1 lb. of potash of commerce, or 5 lbs. of unleached wood-ashes; as regards phosphoric and sulphuric acids, by adding 1 lb. of good superphosphate, or 1 lb. each of bone dust and plaster of Paris.

In fact, the additions just named, will convert _any fresh peat_, containing not more than 80 _per cent._ of water and not less than 20 _per cent._ of organic matter, into a mixture having as much fertilizing matters as stable dung, with the possible exception of nitrogen.