VEGETATION EXPERIMENTS IN PEAT COMPOSTS.
KEYA-Weight of crops in grammes.B-Comparative weight of crops, the sum of 1. and 2. taken as unity.C-Ratio of weight of crops to weight of seeds, the latter assumed as unity.Nos.Medium of Growth.ABC1 }Peat alone.1.61 }4.2012-½2 }2.59 }3 }Peat, and ashes of grass,14.19 }32.44820-½4 }18.25 }5 }Peat, ashes, and carbonate of lime,18.19 }38.44925-½6 }20.25 }7 }Peat, ashes, and carbonate of lime,21.49 }42.221028-½8 }20.73 }9 }Peat, ashes, slaked lime, and salt,23.08 }46.421130-½10 }23.34 }11 }Peat, ashes, and Peruvian Guano,26.79 }53.781335-½12 }26.99 }
Let us now examine the above results. The experiments 1 and 2, demonstrate that the peat itself is deficient in something needful to the plant. In both pots, but 4.2 grammes of crop were produced, a quantity two and a half times greater than that of the seeds, which weighed 1.59 grammes. The plants were pale in color, slender, and reached a height of but about six inches.
Nos. 3 and 4 make evident what are some of the deficiencies of the peat. A supply of mineral matters, such as are contained in all plants, being made by the addition ofashes, consisting chiefly of phosphates, carbonates and sulphates of lime, magnesia and potash, a crop is realized nearly eight times greater than in the previous cases; the yield being 32.44 grammes, or 20-½ times the weight ofthe seed. The quantity of ashes added, viz.:—10 grammes, was capable of supplying every mineral element, greatly in excess of the wants of any crop that could be grown in a quart of soil. The plants in pots 3 and 4 were much stouter than those in 1 and 2, and had a healthy color.
The experiments 5 and 6 appear to demonstrate thatcarbonate of limeconsiderably aided in converting the peat itself into plant-food. The ashes alone contained enough carbonate of lime to supply the wants of the plant in respect to that substance. More carbonate of lime could only operate by acting on the organic matters of the peat. The amount of the crop is raised by the effect of carbonate of lime from 32.44 to 38.44 grammes, or from 20-½ to 25-½ times that of the seed.
Experiments 7 and 8 show, thatslaked limehas more effect than the carbonate, as we should anticipate. Its influence does not, however, exceed that of the carbonate very greatly, the yield rising from 38.44 to 42.22 grammes, or from 25-½ to 28-½ times the weight of the seed. In fact, quick-lime can only act as such for a very short space of time, since it rapidly combines with the carbonic acid, which is supplied abundantly by the peat. In experiments 7 and 8, a good share of the influence exerted must therefore be actually ascribed to the carbonate, rather than to the quick-lime itself.
In experiments 9 and 10, we have proof that the "lime and salt mixture" has a greater efficacy than lime alone, the crop being increased thereby from 42.22, to 46.42 grammes, or from 28-½ to 30-½ times that of the seed.
Finally, we see from experiments 11 and 12 that in all the foregoing cases it was a limited supply ofnitrogenthat limited the crop; for, on adding Peruvian guano, which could only act by this element (its other ingredients,phosphates of lime and potash, being abundantly supplied in the ashes), the yield was carried up to 53.78 grammes, or 35-½ times the weight of the seed, and 13 times the weight of the crop obtained from the unmixed peat.
5.—The Examination of Peat (muck and marsh-mud) with reference to its Agricultural Value.
Since, as we are forced to conclude, the variations in the composition of peat stand in no recognizable relations to differences of appearance, it is only possible to ascertain the value of any given specimen by actual trial or by chemical investigation.
The methodby practical trialis usually the cheaper and more satisfactory of the two, though a half year or more is needful to gain the desired information.
It is sufficient to apply to small measured plots of ground, each say two rods square, known quantities of the fresh, the weathered, and the composted peat in order, by comparison of the growth andweightof the crop, to decide the question of their value.
Peat and its composts are usually applied at rates ranging from 20 to 40 wagon or cart loads per acre. There being 160 square rods in the acre, the quantity proper to a plot of two rods square (= four square rods,) would be one half to one load.
The composts with stable manure and lime, or salt and lime mixture, are those which, in general, it would be best to experiment with. From the effects of the stable manure compost, could be inferred with safety the value of any compost, of which animal manure is an essential ingredient.
One great advantage of the practical trial on the small scale is, that the adaptation of the peat or of the compost to thepeculiarities of the soil, is decided beyond a question.
It must be borne in mind, however, that the results of experiments can only be relied upon, when the plots are accurately measured, when the peat, etc., are applied in known quantities, and when the crops are separately harvested and carefully weighed.
If experiments are made upon grass or clover, the gravest errors may arise by drawing conclusions from the appearance of the standing crop. Experience has shown that two clover crops, gathered from contiguous plots differently manured, may strikingly differ in appearance, but yield the same amounts of hay.
Thechemical examinationof a peat may serve to inform us, without loss of time, upon a number of important points.
To test a peat forsoluble iron saltswhich might render it deleterious, we soak and agitate a handful for some hours, with four or five times its bulk of warm soft water. From agood fresh-water peatwe obtain, by this treatment, a yellow liquid, more or less deep in tint, the taste of which is very slight and scarcely definable.
From avitriol peatwe get a dark-brown or black solution, which has a bitter, astringent, metallic or inky taste, like that of copperas.
Salt peatwill yield a solution having the taste of salt-brine, unless it contains iron, when the taste of the latter will prevail.
On evaporating the water-solution to dryness and heating strongly in a China cup, avitriol peatgives off white choking fumes of sulphuric acid, and there remains, after burning, brown-red oxide of iron in the dish.
The above testings are easily conducted by any one, with the ordinary conveniences of the kitchen.
Those that follow, require, for the most part, the chemical laboratory, and the skill of the practised chemist, for satisfactory execution.
Besides testing for soluble iron compounds, as already indicated, the points to be regarded in the chemical examination, are:—
1st.Water or moisture.—This must be estimated, because it is so variable, and a knowledge of its quantity is needful, if we will compare together different samples. A weighed amount of the peat is dried for this purpose at 212° F., as long as it suffers loss.
2d. Theproportions of organic matter and ashare ascertained by carefully burning a weighed sample of the peat. By this trial we distinguish between peat with 2 to 10per cent.of ash and peaty soil, or mud, containing but a fewper cent.of organic matter.
This experiment may be made in a rough way, but with sufficient accuracy for common purposes, by burning a few lbs. or ozs. of peat upon a piece of sheet iron, or in a sauce pan, and noting the loss, which includes bothwaterandorganic matter.
3d. As further regards the organic matters, we ascertainthe extent to which the peaty decomposition has taken placeby boiling with dilute solution of carbonate of soda. This solvent separates the humic and ulmic acids from the undecomposed vegetable fibers.
For practical purposes this treatment with carbonate of soda may be dispensed with, since the amount of undecomposed fiber is gathered with sufficient accuracy from careful inspection of the peat.
Special examination of the organic acids is of no consequence in the present state of our knowledge.
4th. Theproportion of nitrogenis of the first importance to be ascertained. In examinations of 30 samples of peat, I have found the content of nitrogen to range from 0.4 to 2.9per cent., the richest containing seven times as much as the poorest. It is practically a matter of greatmoment whether, for example, a Peruvian guano contains 16per cent.of nitrogen as it should, or but one-seventh that amount, as it may when grossly adulterated. In the same sense, it is important before making a heavy outlay in excavating and composting peat, to know whether (as regards nitrogen) it belongs to the poorer or richer sorts. This can only be done by the complicated methods known to the chemist.
5th. The estimation ofammonia(actual or ready-formed,) is a matter of scientific interest, but subordinate in a practical point of view.
6th.Nitric acidandnitratescan scarcely exist in peat except where it is well exposed to the air, in a merely moist but not wet state. Their estimation in composts is of great interest, though troublesome to execute.
7th. As regards the ash, its red color indicatesiron. Pouring hydrochloric acid upon it, causes effervescence in the presence ofcarbonate of lime. This compound, in most cases, has been formed in the burning, from humate and other organic salts of lime.Sand, orclay, being insoluble in the acid, remains, and may be readily estimated.
Phosphoric acidand alkalies, especiallypotash, are, next to lime, the important ingredients of the ash.Magnesiaandsulphuric acid, rank next in value. Their estimation requires a number of tedious operations, and can scarcely be required for practical purposes, until more ready methods of analyses shall have been discovered.
8th. The quantity ofmatters soluble in waterhas considerable interest, but is not ordinarily requisite to be ascertained.
6.—Composition of Connecticut Peats.
In the years 1857 and 1858, the author was charged by the Connecticut State Agricultural Society[8]with thechemical investigation of 33 samples of peat and swamp muck, sent to him in compliance with official request.
In the foregoing pages, the facts revealed by the laborious analyses executed on these samples, have been for the most part communicated, together with many valuable practical results derived from the experience of the gentlemen who sent in the specimens. The analytical data themselves appear to me to be worthy of printing again, for the information of those who may hereafter make investigations in the same direction.—See Tables I, II, and III, p.p. 89, 90, and 91.
The specimens came in all stages of dryness. Some were freshly dug and wet, others had suffered long exposure, so that they were air-dry; some that were sent in the moist state, became dry before being subjected to examination; others were prepared for analysis while still moist.
A sufficient quantity of each specimen was carefully pulverized, intermixed, and put into a stoppered bottle and thus preserved for experiment.
The analyses were begun in the winter of 1857 by my assistant, Edward H. Twining, Esq. The samples 1 to 17 of the subjoined tables were then analyzed. In the following year the work was continued on the remaining specimens 18—33 by Dr. Robert A. Fisher. The method of analysis was the same in both cases, except in two particulars.
In the earlier analyses, 1 to 17 inclusive, the treatment with carbonate of soda was not carried far enough to dissolve the whole of the soluble organic acids. It was merely attempted to makecomparativedeterminations by treating all alike for the same time, and with the same quantity of alkali. I have little doubt that in some cases not more than one-half of the portion really soluble in carbonate of soda is given as such. In the later analyses,18 to 33, however, the treatment was continued until complete separation of the soluble organic acids was effected.
By acting on a peat for a long time with a hot solution of carbonate of soda, there is taken up not merely a quantity of organic matter, but inorganic matters likewise enter solution. Silica, oxyd of iron and alumina are thus dissolved. In this process too, sulphate of lime is converted into carbonate of lime.
The total amount of these soluble inorganic matters has been determined with approximate accuracy in analyses 18 to 33.
In the analyses 1 to 17 the collective amount of matters soluble in water was determined. In the later analyses the proportions of organic and inorganic matters in the water-solution were separately estimated.
The process of analysis as elaborated and employed by Dr. Fisher and the author, is as follows:
I. To prepare a sample for analysis, half a pound, more or less, of the substance is pulverized and passed through a wire sieve of 24 meshes to the inch. It is then thoroughly mixed and bottled.
II. 2 grammes of the above are dried (in tared watch-glasses) at the temperature of 212 degrees, until they no longer decrease in weight. The loss sustained represents theamount of water, (according toMarsilly, Annales des Mines, 1857, XII., 404, peat loses carbon if dried at a temperature higher than 212 degrees.)
III. The capsule containing the residue from I. is slowly heated to incipient redness, and maintained at that temperature until the organic matter is entirely consumed. The loss gives the total amount oforganic, the residue the total amount ofinorganicmatter.
Note.—In peats containing sulphate of the protoxide of iron, the loss that occurs during ignition is partly dueto the escape of sulphuric acid, which is set free by the decomposition of the above mentioned salt of iron. But the quantity is usually so small in comparison with the organic matter, that it may be disregarded. The same may be said of the combined water in the clay that is mixed with some mucks, which is only expelled at a high temperature.
IV. 3 grammes of the sample are digested for half an hour, with 200 cubic centimeters (66.6 times their weight,) of boiling water, then removed from the sand bath, and at the end of twenty-four hours, the clear liquid is decanted. This operation is twice repeated upon the residue; the three solutions are mixed, filtered, concentrated, and finally evaporated to dryness (in a tared platinum capsule,) over a water bath. The residue, which must be dried at 212 degrees, until it ceases to lose weight, gives thetotal amount soluble in water. The dried residue is then heated to low redness, and maintained at that temperature until the organic matter is burned off. The loss represents the amount oforganic matter soluble in water, the ash gives the quantity ofsoluble inorganic matter.
V. 1 gramme is digested for two hours, at a temperature just below the boiling point, with 100 cubic centimeters of a solution containing 5per cent.of crystallized carbonate of soda. It is then removed from the sand bath and allowed to settle. When the supernatant liquid has become perfectly transparent, it is carefully decanted. This operation is repeated until all the organic matter soluble in this menstruum is removed; which is accomplished as soon as the carbonate of soda solution comes off colorless. The residue, which is to be washed with boiling water until the washings no longer affect test papers, is thrown upon a tared filter, and dried at 212 degrees. It is thetotal amount of organic and inorganicmatter insoluble in carbonate of soda. The loss that it suffers upon ignition, indicates the amount oforganic matter, the ash gives theinorganicmatter.
Note.—The time required to insure perfect settling after digesting with carbonate of soda solution, varies, with different peats, from 24 hours to several days. With proper care, the results obtained are very satisfactory. Two analyses of No. 6, executed at different times, gavetotal insoluble in carbonate of soda—1st analysis 23.20per cent.; 2d analysis 23.45per cent.These residues yielded respectively 14.30 and 14.15per cent.of ash.
VI. The quantity oforganic matter insoluble in water but soluble in solution of carbonate of soda, is ascertained by deducting the joint weight of the amounts soluble in water, and insoluble in carbonate of soda, from the total amount of organic matter present. Theinorganic matter insoluble in water, but soluble in carbonate of soda, is determined by deducting the joint weight of the amounts of inorganic matter soluble in water, and insoluble in carbonate of soda, from the total inorganic matter.
VII. The amount of nitrogen is estimated by the combustion of 1 gramme with soda-lime in an iron tube, collection of the ammonia in a standard solution of sulphuric acid, and determination of the residual free acid by an equivalent solution of caustic potash and a few drops of tincture of cochineal as an indicator.
The results of the analyses are given in the following Tables. Table I. gives the direct results of analysis. In Table II. the analyses are calculated on dry matter, and the nitrogen upon the organic matters. Table III. gives a condensed statement of the external characters and agricultural value[9]of the samples in their different localities, and the names of the parties supplying them.
TABLE I.—COMPOSITION OF CONNECTICUT PEATS AND MUCKS.
KEYA -Soluble in water.B -Insol. in water, but soluble in carbonate of soda.C -Insol. in water and carbonate of soda.D -Total.E -Water.F -Nitrogen.G -Total matters soluble in water.From Whom and Whence Received.ORGANIC MATTER.INORGANIC MATTER.ABCDABCDEFG1. Lewis M. Norton17.6334.7952.4235.2112.371.281.54Goshen, Conn.2. Lewis M. Norton60.0211.6571.678.0020.331.85Goshen, Conn.3. Lewis M. Norton50.6029.7580.354.5215.131.902.51Goshen, Conn.4. Messrs. Pond & Miles65.1511.9577.103.2319.671.201.63Milford, Conn.5. Messrs. Pond & Miles67.7516.6584.402.0013.60.953.42Milford, Conn.6. Samuel Camp43.208.9052.1014.9014.3029.2018.702.102.50Plainville, Conn.7. Russell U. Peck38.4930.5169.0013.5917.411.622.61Berlin, Conn.8. Rev. B. F. Northrop42.3010.1552.4534.7012.851.311.64Griswold, Conn.9. J. H. Stanwood49.657.4057.054.5738.381.231.83Colebrook, Conn.10. N. Hart, Jr.55.1110.2965.4014.8919.712.106.20West Cornwall, Conn.11. A. L. Loveland38.272.8941.1647.2411.601.00.75North Granby, Conn.12. Daniel Buck, Jr.27.1948.8476.035.9218.052.402.94Poquonock, Conn.13. Daniel Buck, Jr.33.6640.5174.178.6317.202.401.80Poquonock, Conn.14. Philip Scarborough51.4525.0076.457.6715.881.201.43Brooklyn, Conn.15. Adams White54.3823.1477.529.0313.452.895.90Brooklyn, Conn.16. Paris Dyer18.865.0223.8867.778.351.032.63Brooklyn, Conn.17. Perrin Scarborough43.2716.8360.1025.7814.120.8615.13Brooklyn, Conn.18. Geo. K. Virgin2.2120.578.2531.030.329.4148.0557.7811.190.642.53Collinsville, Conn.19. Geo. K. Virgin1.129.195.1015.410.281.0848.6550.0134.580.341.40Collinsville, Conn.20. Geo. K. Virgin0.729.313.6513.680.250.7628.2029.2157.110.28.97Collinsville, Conn.21. S. Mead3.3040.528.2052.022.6010.0223.9036.5211.461.515.90New Haven, Conn.22. Edwin Hoyt2.8413.427.5523.812.7219.8846.3068.907.290.455.56New Canaan, Conn.23. Edwin Hoyt2.3413.498.0523.881.5412.4256.2070.165.960.903.88New Canaan, Conn.24. Edwin Hoyt1.1517.298.0026.441.6714.1351.1066.906.661.012.82New Canaan, Conn.25. A. M. Haling3.4352.158.6564.230.350.164.905.4130.361.623.78Rockville, Conn.26. A. M. Haling3.8771.578.4483.880.231.982.2113.911.324.10Rockville, Conn.27. A. M. Haling3.8744.044.2552.160.514.075.059.6338.211.884.38Rockville, Conn.28. Albert Day2.4546.256.3555.050.320.655.406.3738.580.842.77Brooklyn, Conn.29. C. Goodyear1.8045.4210.3557.570.357.9818.8027.1315.301.682.15New Haven, Conn.30. Rev. Wm. Clift3.3351.689.8064.812.825.868.6826.510.956.15Stonington, Conn.31. Henry Keeler2.1345.1212.0559.300.783.7916.7021.2719.431.572.91South Salem, N. Y.32. John Adams1.7142.8710.6555.231.021.3314.3516.7028.071.762.73Salisbury, Conn.33. Rev. Wm. Clift5.4016.727.2529.377.406.4048.0561.858.781.322.80Stonington, Conn.Average2.061.441.373.72
TABLE II.—COMPOSITION OF CONNECTICUT PEATS AND MUCKS.
Calculated in the dry state: the percentage of nitrogen calculated also on organic matters.