Treatise on Agriculture.

SECT. IV.

Of the Analysis of Soils, and of the agricultural relations between soils and plants.

We have seen that the earths have a threefold capacity; that they receive and lodge the roots of plants and support their stems; that they absorb and hold air, water and mucilage—aliments necessary to vegetable life; and that they even yield a portion of themselves to these aliments. But we have also seen, that they are not equally adapted to these offices; that their parts, texture and qualities are different; that they are cold or warm, wet or dry, porous or compact, barren or productive, in proportion as one or other may predominate in the soil; and that to fit them for discharging the various functions to which they are destined, each must contribute its share, and all be minutely divided and intimately mixed. In this great work nature has performed her part, but as is usual with her, she has wisely and benevolently left something for man to do.

This necessary march of human industry, obviously begins by ascertaining the nature of the soil. But neither the touch, nor the eye, however practised or acute, can in all cases determine this. Clay, when wet, is cold and tenacious—a description that belongs also to magnesian earths: sand and gravel are hard and granular; but so also are some of the modifications of lime: vegetable mould is black and friable, but not exclusively so; for schistous and carbonaceous earths have the same properties.

It is here, then, that chemistry offers herself to obviate difficulties, and remove doubts; but neither the apparatus nor process of this science, are within the reach of all who are interested in the inquiry, and we accordingly subjoin a method, less comprehensive, but more simple and sufficiently exact, for agricultural purposes, and which calls only for two vases, a pair of scales, clean water and a little sulphuric acid.

"1st. Take a small quantity of earth from different parts of the field, the soil of which you wish to ascertain, mix them well together and weigh them; put them in an oven, heated for baking bread, and after they are dried, weigh them again; the difference will show the absorbent power of the earth. When the loss of weight in 400 grains, amounts to 50, this power is great, and indicates the presence of much animal or vegetable matter; but when it does not exceed twenty, the absorbent power is small, and the vegetable matter deficient.[2]

"2d. Put the dried mass into a vase with one fourth of its own weight of clear water; mix them well together: pour off the dirty water into a second vase, and pour on as much clean water as before; stir the contents, and continue this process until the water poured off, is as clear as that poured on the earth. What remains in the first employed vase is sand, silicious or calcareous.

"3d. The dirty water, collected in the second vase, will form a deposit, which (after pouring off the wa-ter) must be dried, weighed and calcined. On weighing it after this process, the quantity lost will show the portion of animal and vegetable mould contained in the soil; and,

"4th. This calcined matter must then be carefully pulverised and weighed, as also the first deposit of sand, but without mixing them. To these, apply (separately) sulphuric acid, and what they respectively lose in weight, is the portion of calcareous or aluminous earths contained in them. These last may be separated from the mass by soap lie, which dissolves them."[3]

Here is the light we wanted. In knowing the disease, we find the cure. Clay and sand qualify each other; either of these will correct an excess of lime; and magnesian earth, when saturated with carbonic acid, becomes fertile.

But entirely to alter the constitution of a soil, whether by mechanical or other means, is a work of time, labour and expense, and little adapted to the pecuniary circumstances of farmers in general. Fortunately, a remedy, cheaper, more accessible and less difficult, is found in that great diversity of habits and character, which mark the vegetable races. We shall, therefore, in what remains of this section, indicate the principal of these, as furnishing the basis of all rational agriculture.

1st. Plants have different systems of roots, stems and leaves, and adapt themselves accordingly to different kinds of soils: the Tussilago prefers clay, the Spergula sand; Asparagus will not flourish on a bed of granite nor Musus Islandicus on one of alluvion. It is obvious, that fibrous rooted plants, which occupy only the surface of the earth, can subsist on comparatively stiff and compact soils in which those of the leguminous and cruciform families would perish, from inability to penetrate and divide.

2d. Plans of the same, or of a similar kind, do not follow each other advantageously in the same soil. Every careful observer must have seen how grasses alternate in meadows or pastures, where nature is left to herself. At one time, timothy, at another clover, at a third red-top, and at a fourth blue grass prevails. The same remark applies to forest trees; the original growth of wood, is rarely succeeded by a second of the same kind; pine is followed by oak, oak by chesnut, chesnut by hickory. A young apple tree will not live in a place where an old one has died; even the pear tree does not thrive in succession to an apple tree, but stone fruit will follow either with advantage. "In the Gautinois (says Bosc,) saffron is not resumed but after a lapse of twenty years; and in the Netherlands, flax and colzat require an interval of six years. Peas, when they follow beans, give a lighter crop than when they succeed plants of another family."[4]

3d. Vegetables, whether of the name family or not, having a similar structure of roots, should not succeed each other. It has been observed, that trees suffer considerably by the neighbourhood of sainfoin and lucern, on account of the great depth to which the roots of these plants penetrate—whereas culmiferous grasses do them no harm.

4th. Annual or biennial trefoils, prevent the escape of moisture by evaporation, or filtration, from sandy and arid soils, and should constantly cover them in the absence of other plants;[5] while drying and dividing crops, as beans, cabbages, chickory, &c. &c. are best fitted to correct the faults of stiff and wet clays.

5th. When plants, are cultivated in rows or hills, and the ground between them is thoroughly worked, the earth is kept open, divided and permeable to air, heat and water, and accordingly receives from the atmosphere nearly as much alimentary provision as it gives to the plant. This principle is the basis of the drill husbandry.

6th. All plants permitted to go through the phases of vegetation (and of course to give their seeds) exhaust the ground in a greater or less degree; but if cut green, and before seeding, they take little from the principle of fertility.

7th. Plants are exhausters in proportion to the length of time they occupy the soil. Those of the culmiferous kinds (wheat, rye, &c.) do not ripen under ten months, and during this period, forbid the earth from being stirred: while, on the other hand, leguminous plants occupy it but six months, and permit frequent ploughings. This is one reason why culmiferous crops are greater exhausters than leguminous; another is, that the stems of culmiferous plants become hard and flinty, and their leaves dry and yellow, from the time of flowering till the ripening of the seed—losing their inhaling or absorbing faculties—circulating no juices, and living altogether in their roots, and on aliments exclusively derived from the earth, whereas leguminous or cruciferous plants, as cabbages, turnips, &c. &c. have succulent stems, and broad and porous leaves, and draw their principal nourishment from the atmosphere. The remains of culmiferous crops, also are fewer, and less easily decomposed, than those of the leguminous family.

8th. Meadows, natural and artificial, yield the food necessary to cattle, and, in proportion as these are multiplied, manures are increased and the soil made better. Another circumstance that recommends them is, that so long as they last, they exact but little labour, and leave the whole force of the farmer to be directed to his arable grounds.[6]

9th. Grasses are either fibrous or tap-rooted, or both. The remarks already made in articles 1, 2 and 3, apply also to them. Timothy, red-top, oat-grass and rye-grass, succeed best in stiff, wet soils. Sainfoin does well on soils the most bare, mountainous and arid; lucern and the trefoils, (or clovers,) only attain the perfection of which they are susceptible, in warm, dry, calcareous earth.

10th. The ameliorating quality of tap-rooted plants is supposed to be in proportion to their natural duration; annual clover, (lupinella) has less of this property than biennial, (Dutch clover,) biennial less than sainfoin, and sainfoin less than lucern.

11th. Any green crop, ploughed into the soil, has an effect highly improving; but for this purpose, lupins and buckwheat (cut when in flower) are most proper.

12. Mixed crops (as Indian corn, pumpkins, and peas and oats,) are much and profitably employed, and with less injury to the soil than either corn or oats alone.

SECTION V.

Of Practical Agriculture, and its necessary Instruments.

We begin this part of our subject with a few remarks on the instruments necessary to agriculture, which may be comprised under the well known names of the plough, the harrow, the roller, the threshing-machine, and the fanning mill.

I. Of the plough:

It is among the inscrutable dispensations of Providence, that the arts most useful to man, have been of later discovery—of slower growth, and of less marked improvement, than those that aimed only at his destruction.—At a time, when the phalanx and the legions were invented and perfected, and when the instruments they employed were various and powerful, those of agriculture continued to be few, and simple, and inefficient.

Of the Greek plough, we know nothing; and the general disuse of that described by Virgil and Pliny, furnishes a degree of evidence, that experience has found it incompetent to its objects.—With even the boasted lights of modern knowledge, scientific men are not agreed upon the form and proportion, most proper for this instrument. As in other cases, so in this, there may be no abstract perfection; what is best in one description of soil, may not be so in another; yet, as in all soils, the office of the plough is the same, viz. to cleave and turn over the earth, there cannot but be some definite shape and proportions, better fitted for these purposes, and at the same time less susceptible of resistance, than any other.

This beau ideal, this suppositious excellence, in the mechanism of a plough, has been the object of great national, as well as individual research. In Great Britain, high prizes have been established for its attainment; and in France, under the ministry of Chaptal, 10,000 francs, or $2000, were offered for this object, by the agricultural society of the Seine. In both countries, the subject has employed many able pens; those of Lord Kaimes, of Mr. Young, of Mr. Arbuthnot, of Lord Somerville, and of Messieurs Duhamel, Chateauvieux, Bosc, Guillaume, &c. It is not for us, therefore, to do more than assemble and present such rules for the construction of this instrument, as have most attained the authority of maxims.

1st. The beam, or that part of the plough which carries the coulter, and furnishes the point of draft, should be as near that of resistance as possible; because the more these are approached, the less is the moving power required. Even the shape of the beam is not a matter of indifference. In the old ploughs, it was generally straight, but a small curve is now preferred; because it has the effect of strengthening the coulter, by shortening it.

2d. The head of the plough, is the plain on which it moves. This should be concave, because that form offers fewer points of friction, and, of course, less resistance. Between the beam and the head, is an angle, on which depends the principal office of the plough; the making, at will, a deep or a shallow furrow. If you wish a deep furrow, diminish the angle, and vice versa: but this angle should, in no case, exceed from 18 to 24 degrees.

The resistance made to the plough being produced less by the weight of the earth, than by the cohesion of its parts, it is evident, that the head should be shod with iron, and rendered as smooth as possible. This remark applies equally to the soc and to the mould board.

3d. The soc, in its widest part, should be larger than the head. It has different shapes in different countries. In some is given to it that of an isosceles triangle; in others, that of the head of a lance; in Biscay, that of a crescent; and in Poland, of a two pronged fork. But, whatever be its shape, it should be well pointed and polished—enter the earth with facility, and cut it easily.

4th. To the mould board, some workmen give the shape of a prismatic wedge; others make the upper part convex, and the lower concave; while many make it entirely flat. In stiff soils, the semi cycloid is the form to be preferred, and in loose friable soils the semi-ellipsis.[7] The iron mould boards have great advantages over the wooden, particularly when they, the shear and the soc, form one piece, as in the plough of Mr. Cook.

It is a general opinion, that a heavy plough is more disadvantageous than a light one; because the draft of the former, being greater, will be more fatiguing to the cattle: but the experiments of the agricultural society in London, establish a contrary doctrine, and show, that in light grounds, the labour is more easily and better performed, with a heavy, than with a light plough.

5th. The coulter is a species of knife inserted in the beam, and so placed before the soc, as to cut the sod. It is susceptible of being raised or depressed at will.

6th. The handles of the plough ought to be made of some kind of heavy wood, that they may operate as a counter-weight to the head, the soc and the mould-board.

To these remarks we subjoin two sets of experiments made with the most approved French and English ploughs; that of Guillaume, and Small's Rotheram plough improved, which furnish a means of comparison between the best ploughs of Europe and those of this country.

The resistance (stated in these tables) was measured and ascertained by a dynonometer, a machine, indispensable to those who would make correct observations on the relative advantages of different ploughs.

The French Plough.The English Plough.

Resistance in pounds.Resistance in pounds.

1stexperiment200 1stexperiment360

2ddo.2402ddo.380

3ddo.2003ddo.480

4thdo.2204thdo.460

5thdo.2205thdo.400

6thdo.400

Divided by5)10807thdo.420

8thdo.386

Average,2169thdo.440

Divided by9)3720

Average,413

II. The Harrow. This is of different kinds—the triangular and the square, the single and the double. But of whatever form, its uses are the same; to smooth the field after ploughing, to break and pulverize the clods, and to cover the seed.—These uses sufficiently indicate the propriety of employing two in succession; one of heavy frame, with few and long teeth, like the Scotch brake; the other, of lighter constitution, with more and shorter teeth. Our own experience leads us to believe, that the common harrow covers the seed too much, because small seeds will not vegetate at a depth greater than three inches.

III. The Roller is a cylinder of heavy wood, turning on gudgeons, or on an axle, and placed in a frame, to which is attached a shaft; it is of different dimensions, but need not exceed that which may be drawn by one, or at most by two horses or oxen. This instrument is indispensable in good husbandry, yet is rarely used in ours. Its offices are three-fold—to render loose soils more compact; to break the clod on stiff ones, and on both, to compress the earth, (after seeding) so that it be every where brought in contact with the grain. It is also usefully employed in reinstating the roots of meadow grasses, loosened and raised by the alternate freezing and thawing of the ground, and, with similar view, may be passed over winter crops early in the spring.

Its clod-breaking and pulverizing property is much increased, by surrounding the roller with narrow bands of iron, two inches broad, three inches thick, and six inches asunder; or by studding it with iron points, resembling harrow teeth, and projecting three or four inches.

IV. The Threshing Machine is of English invention, and may be well enough adapted to the taste and circumstances of rich amateurs, but not at all to those of farmers in general. Our objections to it are three—the first cost, which is great; the quantum of moving power employed, which is equal to that of six horses, and the number of hands required to attend it, which is not less than four. We have seen, in France, a machine for the same purpose, but of much simpler structure—called the "Rouleau de depiquer" which is only a fluted cylinder; yet simple and cheap as this was, it could not maintain itself against the more ancient instruments—the flail and the horse. Still it is to be hoped, that new experiments may succeed better and abridge the manual labour usually given to this branch of husbandry, and, that the mechanical genius of our own country (which is not inferior to that of any other) may be the first to combine power and cheapness in this machine.

This hope is probably suggested, by the description of a new invented threshing machine, now before me, and which I may be permitted to transcribe from the letter of the inventor. "The machine I have built, is three feet wide. One horse will thresh with much ease, as much wheat as can be laid on it, by one man, (the straw to be taken away by another,) say, from fifty to one hundred bushels in a day, and the saving of grain will pay for the labour; for, I think, that with good attendance, not a particle of grain can escape with the straw.—The expense of the machine will be from fifty to seventy dollars, exclusive of the moving power, which is a wheel, about ten feet diameter, on an upright shaft, to which a lever is fixed to hitch the horse. Into this main wheel, a small one should be made to work, about two feet diameter, on a shaft carrying a drum, four feet wide. With this simple gearing, and drawn by a horse that walks well, the machine will give about eighteen hundred strokes in a minute, and if fully attended, will, without hard labour for the horse, thresh a bushel every three or four minutes. It stands in my barn, and may be seen and examined by any one."[8]

V. The Fanning Mill. Other things being equal, the cleanest wheat is most easily preserved, and, on manufacture, gives the best flour, and in the largest quantity. These considerations offer inducement enough for the employment of this machine, which, however, besides doing its business well, saves a great deal of time. It is too well known to require description.