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putrescent animal and vegetable matters, which much more generally in Britain than here: and it exerts on every such substance in the soils to indeed that there are very few cases in which the which it is applied as manure. If the lime thus caustic quality would not do our arable lands more meets with solid and inert vegetable matters, it harm than good. This is no contradiction of the hastens their decomposition, renders them soluble, great improvements which have been made on and brings them into use and action as manure. some farms by applying lime--because its caustic But such vegetable and animal matters as were quality was seldom allowed to act at all. Lime is already decomposed, and fit to support growing continually changing to the carbonate of lime, and plants, are injured by the addition of lime-as the in practice, no exact line of separation can be chemical action which takes place between these drawn between the transient effects of the one, and bodies, forms different compounds which are al- the later, but durable improvement from the other. ways less valuable than the putrid or soluble mat- Lime powerfully attracts the carbonic acid, of which ters were, before being acted on by the lime. it was deprived by heat, and that acid is univer[Agr. Chem. Lecture 7.] sally diffused through the atmosphere (though in This theory of Davy's, will direct us to expect a very small proportion,) and is produced by every profit from liming all soils containing much unrot-decomposing putrescent substance. Consequently ted and inert vegetable matter, as our acid wood-caustic lime on land, is continually absorbing and land when first cleared, and perhaps worn fields, combining with this acid; and with more or less covered with broom grass-and to avoid the ap- rapidity, according to the manner of its application, plication of lime, or (what is the same thing,) to is returning to its former state of mild calcareous destroy previously its caustic quality by exposure earth. If spread as a top dressing on grass lands to the air, on all good soils containing soluble ve--or on ploughed land, and superficially mixed getable or animal matters, and on all poor soils with the soil by harrowing-or used in composts deficient in inert, as well as active nourishment with fermenting vegetable matter-the lime is profor plants. The warmth of our climate so much bably completely carbonated, before its causticity aids the fermentation of all putrescent matters in can act on the soil. In no case can lime, applied soils, that it can seldom be required to hasten it by properly as manure, long remain caustic in the artificial means: to check its rapidity is much more soil. Thus most applications of lime are simply necessary, to avoid the waste of manures in our applications of calcareous earth, but acting with lands. But in England, and still more in Scotland, greater power at first, in proportion to its quantity, the case is very different. There, the coldness because more finely divided, and more equally and moisture of the climate greatly retard the fer- distributed.

mentation of the vegetable matter that falls on the By adopting the views which have been preland-so much so, that in certain situations the sented of the action of calcareous earth, and of most favorable to such results, the vegetable cover lime, as manures, and those which are generally is increased by the deposite of every successive received as to the mode of operation of other mayear, and forms those vegetable soils, which are nures, the following table has been constructed, called moor, peat, and bog lands. Vegetable mat- which may be found useful, though necessarily ter abounds in these soils, sometimes it even forms imperfect, and in part founded only on conjecture. the greater bulk for many feet in depth-but it is The various particular kinds of manures are arinert, insoluble, and useless, and the soil is unable ranged in the supposed order of their power, under to bring any useful crop, though containing vege- the several heads or characters to which they betable matter in such excess. Many millions of long; and when one manure possesses several difacres in Britain, are of the different grades of peat ferent modes of action, the comparative force of soils, of which not an acre exists in the eastern each is represented by the letters annexed-the half of Virginia. Upon this ground of the differ- letter a designating its strongest or most valuable ence of climate, and its effects on fermentation, I agency, b the next strongest, and so on. deduce the opinion that lime would be serviceable

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CHAPTER IX.

PART II-Practice.

GENERAL OBSERVATIONS ON MARL AND LIME.
EFFECTS OF CALCAREOUS MANURES
ON
ACID SANDY SOILS, NEWLY CLEARED.

persons will consider both operations as similar, and perhaps may refer to English authorities for the purpose of testing the truth of my opinions, and the results of my practice. But no two operations called by the same name, can well differ more. The process which it is my object to rePROPOSITION 5. Calcareous manures will give commend, is simply the application of calcareous to our worst soils a power of retaining putres- earth in any form whatever, to soils wanting that cent manures, equal to that of the best-and will ingredient, and generally quite destitute of it: and cause more productiveness, and yield more profit, the propriety of the application depends entirely than any other improvement practicable in Lower on our knowing that the manure contains calVirginia. careous earth, and what proportion, and that the soil contains none. In England, the most scienThe theory of the constitution of fertile and tific agriculturists apply the term marl correctly to barren soils, has now been regularly discussed: it a calcareous clay, of peculiar texture: but most remains to show its practical application, in the authors, as well as mere cultivators, have used it use of calcareous earth as a manure. If the opin- for any smooth soapy clay, which may, or may ions which have been maintained are unsound, not have contained, so far as they knew, any prothe attempt to reduce them to practice will surely portion of calcareous matter. Indeed, in most expose their futility: and if they pass through that cases, they seem unconscious of the presence, as trial, agreeing with, and confirmed by facts, their well as of the importance of that ingredient, by truth and value must stand unquestioned. The not alluding to it when attempting most carefully belief in the most important of these opinions, to point out the characters by which marl may be (the incapacity of poor soils for improvement, and known. Still less do they inquire into the deficiency its cause;) directed the commencement of my use of calcareous earth in soils proposed to be marled of calcareous manures; and the manner of my-but apply any earths which either science or practice has also been directed entirely by the ignorance may have called marl, to any soils within views which have been exhibited. Yet in every a convenient distance-and rely upon the subserespect the results of practice have sustained the quent effects to direct whether the operation shall theory of the action of calcareous manures-unless be continued or abandoned. Authors of the highthere be found an exception in the damage which est character, (as Sinclair and Young, for examhas been caused by applying too heavy dressings ple,) when telling of the practical use, and valuato weak lands. ble effects of marl, omit giving the strength of the

My use of calcareous earth as manure, has been manure, and generally even its nature-and in no almost entirely confined to that form of it which instance have I found the ingredients of the soil is so abundant in the neighborhood of our tide-stated, so that the reader might learn what kind of waters-the beds of fossil shells, together with the operation really was described, or be enabled to earth with which they are found mixed. The form a judgement of its propriety. From all this, shells are in various states-in some beds generally it follows that though what is called marling in whole, and in others, reduced nearly to a coarse England may sometimes (though very rarely, as powder. The earth which fills their vacancies, I infer) be the same chemical operation on the soil and serves to make the whole a compact mass, in that I am recommending, yet it may also be, either most cases is principally silicious sand, and con- applying clay to sand, or clay to chalk, or true tains no putrescent or valuable matter, other than marl to either of those soils-and the reader will the calcareous. The same effects might be ex- generally be left to guess in every separate case, pected from calcareous earth in any other form, which of all these operations is meant by the term whether chalk, limestone gravel, wood ashes, or marling. For these reasons, the practical knowlime-though the two last have other qualities be- ledge to be gathered from all this mass of written sides the calcareous. During the short time that instruction on marling, will be far less abundant, lime can remain quick or caustic, after being ap- than the inevitable errors and mistakes. The replied as manure, it exerts (as before stated) a commendations of marl by English authors, insolvent power, sometimes beneficial and at others duced me very early to look to what was here hurtful, which has no connexion with its subse- called by the same name, as a means for improvequent and permanent action as calcareous earth. ment: but their descriptions of the manure conThese natural deposites of fossil shells are com- vinced me that our marl was nothing like theirs, monly, but very improperly, called marl. This and thus actually deterred me from using it, untıl misapplied term is particularly objectionable, be- other views instructed me that its value did not cause it induces erroneous views of this manure. depend on its having "a soapy feel," or on any Other earthy manures have long been used in mixture of clay whatever. [Appendix. G.] England under the name of marl, and .numerous Nevertheless, much valuable information may publications have described their general effects, be obtained from these same works, on calcareous and recommended their use. When the same manure, or on mart, (in the sense it is used among name is given here to a different manure, many us)—but under a different head, viz. lime. This

require a degree of attention that few readers may be disposed to give, to enable them to derive the full benefit of these details. But however disagreeable it may be to give to them the necessary attention, I will presume to say that these experiments deserve it. They will present practical

theory-and give to this essay its principal claim to be considered useful and valuable,

manure is generally treated of with as little clear-reported by guess. Every measurement stated, ness or correctness, as is done with marl: but the of land, or of crop, was made in my presence. reader at least cannot be mistaken in this, that the The average strength of the manure was ascerultimate effect of every application of lime, must tained by a sufficient number of analyses-and the be to make the soil more calcareous-and to that quantity applied was known by measuring some of cause solely are to be imputed all the long-continu- the loads, and having them dropped at certain ed beneficial consequences, and great profits, which distances. At the risk of being tedious, I shall have been derived from liming, But excepting state every circumstance supposed to affect the this one point, in which we cannot be misled by results of the experiments-and the manner of ignorance, or want of precision, the mass of writ-description, and of reference, necessary to use, will ings on lime, as well as on calcareous manures in general, will need much sifting to yield instruction. The opinions published on the operation of lime, are so many, so various, and contradictory, that it seems as if each author had hazarded a guess, and added it to a compilation of those of all who had preceded him. For a reader of these publica-proofs of what otherwise would be but uncertain tions to be able to reject all that is erroneous in reasoning, and in statements of facts-or inapplicable, on account of difference of soil, or other circumstances and thus obtain only what is true, and valuable-it would be necessary for him first to understand the subject better than most of those whose opinions he was studying. It was not possible for them to be correct, when treating (as most do) of lime as one kind of manure, and every different form of the carbonate of lime, as so many others, Only one distinction of this kind (as to operation and effects) should be made, and never lost sight of-and that is one of substance, still more than of name. Pure or quicklime, and carbonate of lime, are manures entirely different in their powers and effects. But it should be remembered that the substance that was pure lime when just burned, often becomes carbonate of lime before it is used, (by absorbing carbonic acid from the atmosphere,)--still more frequently before a crop is planted-and probably always, before the first crop ripens. Thus, it should be borne in mind that the manure spoken of as lime, is often at first, and always at a later period, neither more nor less than calcareous carth: that lime, which at different periods, is two distinct kinds of manure, is considered in agricultural treatises as only one: and to calcareous earth are given as many different names, all considered to have different values and effects, as there are different forms and mixtures of the substance presented by nature.

But however incorrect and inconvenient the term marl may be, custom has too strongly fixed its application for any proposed change to be adopt ed. Therefore, I must submit to use the word marl to mean beds of fossil shells, notwithstanding my protest against the propriety of its being so applied.

When these operations were commenced, I knew of no other experiments having been made with fossil shells, except two, which had been tried long before, and were considered as proving the manure too worthless to be resorted to again.* Inexperience, and the total want of any practical guide, caused my applications, for the first few years, to be frequently injudicions, particularly as to the quantities laid on. For this reason, these experiments show what was actually done, and the effects thence derived, and not what better information would have directed, as the most profitable course.

The measurements of corn that will be reported were all made at the time and place of gathering,

Spring Garden in Surry, about 1775. The extent marlThe earliest of these old experiments was made at ed was eight or ten acres, on poor sandy land. Nothing is now known of the effects for the first twenty-five or thirty years, except that they were too inconsiderable to induce a repetition of the experiment. The system of cultivation was as exhausting as was usual during that time. Since 1812, the farm has been under mild and improving management generally. No care has been taken to observe the progress either of improvement or exhaustion on the marled piece: but there is no doubt but that the product has continued for the Mr. Francis Ruffin, the present owner of the farm, last fifteen years better than that of the adjacent land. believed that the product was not much increased in favorable seasons; but when the other land suffered either from too much wet, or dry weather, the crop on the marled land was comparatively but slightly injured. The loose reports that have been obtained respecting this experiment, are at least conclusive in showing the permanency of the effects produced.

The other old experiment referred to, was made at Aberdeen, Prince George county, in 1803, by Mr. thirty yards square,) of poor land, kept before and Thomas Cocke. Three small spots (neither exceeding since generally under exhausting culture, were covered with this manure. He found a very inconsiderable early improvement, which he thought altogether an inadequate reward for the labor of applying the marl. The experiment being deemed of no value, was but little noticed until the commencement of my use of the same manure. On examination, the improvement ap

The following experiments are reported, either on account of having been accurately made, and carefully observed, or as presenting such results as have been generally obtained on similar soils, from applications of fossil shells to nearly six hundred acres of Coggin's Point Farm. It has been my habit to make written memoranda of such things; and the material circumstances of these experiments were put in writing at the time they occurred, or not long after. Some of the experi-peared to have increased greatly on two of the pieces, ments were, from their commencement, designed tion. For a number of years after making this exbut the third was evidently the worse for the applicato be permanent, and their results to be measured periment, Mr. Cocke considered it as giving full proof as long as circumstances might permit. These of the worthlessness of the manure. But more correct were made with the utmost care. But generally, views of its mode of operation have since induced him when precise amounts are not stated, the experi- to recommence its use, and no one has met with more ments were less carefully made, and their results success, or produced more valuable improvements.

The measure used for all except very small quan- [surement. For these several reasons, the actual tities, was a barrel holding five bushels when filled increase of product on the marled land was always level, and which being filled twice with ears of greater than will appear from the comparison of corn, well shaken to settle them, and heaped, was quantities measured: and from the statements of estimated to make five bushels of grain-and the all such early measurements, there ought to be products will be reported in grain, according to allowed a deduction, varying from ten per cent. this estimate. This mode of measurement will on the best and most forward corn, to thirty per best serve for comparing results-but in most cases cent. on the latest and most defective. Having it is far from giving correctly the actual quantity stated the grounds of this estimate, practical men of dry and sound grain, for the following reasons. can draw such conclusions as their experience may The common large soft grained white corn was direct, from the dates and amounts of the actual the kind cultivated, and which was always cut measurements that will be reported. Some careful down for sowing wheat before the best matured trials of the amount of shrinkage in particular was dry enough to grind, or even to put up in cribs; experiments will be hereafter stated. and when the ears from the poorest land were in No grazing has been permitted on any land a state to lose considerably more by shrinking. from which experiments will be reported, unless it Yet, for fear of some mistake occurring if measure- is specially stated.

ments were delayed until the crop was gathered, As most of the experiments on new land were these experiments were measured when the land made on a single piece of twenty-six acres a gewas ploughed for wheat in October. The subse-neral description or plan of the whole will enable quent loss from shrinking would of course be great- me to be better understood, as well as to be more est on the corn from the poorest and most back- concise, by references being made to the annexed ward land, as there, most defective and unripe ears figure. It forms part of the ridge lying between would always be found. Besides, every ear, how- James River and the nearest stream running into ever imperfect or rotten, was included in the mea- Powell's Creek. The surface is nearly level. The

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oil in its natural state very similar throughout, but Results. 1818. The corn on the marled land, the part next to the line B C somewhat more sandy, evidently much better-supposed difference, forty and more productive in corn, than the part next per cent. to A D-and in like manner, it is lighter along A

1819. In wheat. The difference as great, per

e, than nearer to D f. The whole soil, a gray haps more so-particularly to be remarked from silicious acid loam, not more than two inches deep the commencement to the end of the winter, by at first, resting on a yellowish sandy subsoil from the marled part preserving a green color, while one to two feet deep, when it changes to clay. the remainder was seldom visible from a short Natural growth mostly pine-next in quantity, distance, and by the spring, stood much thinner, oaks of different kinds--a little of dogwood and chin- from the greater number of plants having been quepin-whortleberry bushes throughout in plenty. killed, The line of separation very perceptible The quality of the soil is better than the average through both crops. of ridge lands in general.

Experiment 1.

1820. At rest. During the summer marled all B C gh, at the rate of five hundred bushels, without excepting the space before covered, and a small part of that made as heavy as one thousand The part B C g h, about eleven acres, grubbed bushels, counting both dressings. The shells now and cut down in the winter of 1814-15-suffered generally coarse-average strength of the marl, to lie three years with most of the wood and brush of calcareous earth. In the winter after,

100

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on it. February 1818, my earliest application of ploughed three inches deep as nearly as could be, marl was made on B C m 1, about 24 acres. Marl, which made the whole new surface yellow, by of calcareous earth, and the balance silicious bringing barren subsoil to the top. sand, except a very small proportion of clay: the Results continued. 1821. In corn. The whole shelly matter finely divided. Quantity of marl to a remarkable growth for such a soil. The oldest the acre, one hundred and twenty-five to two hun-(and heaviest) marled piece better than the other, dred heaped bushels. The whole B C g h coul-but not enough so to show the dividing line. The tered, and planted in its first crop of corn.

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