X. MANURES (cont.)
Sea Weed. Manure Crops. Lime. Marl. Shell Marl.
Along our sea-board large supplies of useful manure are obtained in the shape of drifted sea-weed. This is either applied as a top-dressing to grass and clover, ploughed in with a light furrow, for various crops, or mixed in dung-heaps, It requires to be used in large quantities per acre from 40 to 60 loads --- a and is evanescent in its effects. Grain grown on land manured with sea-weed is generally of fine quality, and is in repute as seed corn.
Crops of Buckwheat, Rape, Vetches, and Mustard are sometimes ploughed in, while in a green, succulent state, to enrich the land. It is, however, more usual to fold sheep on such crops, and so to get the benefit of them as forage, as well as manure to the land. The leaves of turnips are frequently ploughed in after removing the bulbs, and have a powerful fertilizing effect.
Besides manures of an animal and vegetable origin, various mineral substances are used for this purpose. The most important and extensively used of these is lime. In the drier parts of England it is not held in much esteem, whereas in the western and northern counties, and in Scotland, its use is considerable to good farming. Experienced farmers in Berwickshire consider it desirable to lime the land every twelve years, at the rate of from 120 to 200 bushels of the unslacked lime per acre. It is found especially beneficial in the reclaiming of moory and boggy lands, on which neither green nor grain crops thrive until it has been applied to them. Its use is found to improve the quality of grain, and to cause it in some cases to ripen earlier. It facilitates the cleaning of land, certain weeds disappearing altogether for a time after addressing of lime. It is the only known specific for the disease in turnips called "fingers-and toes," on which account alone it is frequently used in circumstances which would otherwise render such an outlay unwarrantable. The practice, still frequent, of tenants at the beginning of a nineteen years lease, liming their whole farm at a cost per acre of from £3 to £5, proves conclusively the high estimation in which this manure is held. The belief --- in which we fully concur --- is however gaining ground, that moderate and frequent applications are preferable to these heavy doses at lengthened intervals.
When bare fallowing was in use, it was commonly towards the close of that process that lime was applied. Having been carted home and laid down in large heaps, it was, when slaked, spread evenly upon the surface and covered in by a light furrow. It is now frequently spread upon the autumn furrow preparatory to root crops, and worked in by harrowing or grubbing, and sometimes by throwing the land into shallow ridgelets. Another method much used is to form it into compost with decayed quickens, parings from road-sides and margins of fields, &c., which, after thorough intermixture by frequent turnings, is spread evenly upon the land when in grass. A cheap and effectual way of getting a dressing of such compost thoroughly comminuted and incorporated with the surface soil, is to fold sheep upon it, and feed them there with turnips for a few days. The value of such compost is much enhanced by mixing common salt with the lime and earth, at the rate of one part of salt by measure to two parts of lime. A mixture of these two substances in these proportions prepared under cover, and applied in a powdery state, is much approved as a spring top-dressing for a corn crops on light soils. In whatever way lime is applied, it is important to remember that the carbonic acid which has been expelled from it by subjecting it in the kiln to a red heat, is quickly regained from the atmosphere, to which therefore it should be as little exposed as possible before applying it to the land. A drenching from heavy rain after it is slaked is also fatal to its usefulness. Careful farmers therefore guard against these evils by laying on lime as soon as it is slaked; or when delay is unavoidable, by coating these heaps with earth, or thatching them with straw. In order to reap the full benefit of a dressing of lime it must be so applied as while thoroughly incorporated with the soil, to be kept near the surface. This is more particularly to be attended to in laying down land to pasture. This fact is so well illustrated by an example quoted in the article "Agriculture" in the 7th edition of the present work that we here repeat it.
"A few years after 1754," says Mr. Dawson, "having a considerable extent of outfield land in fallow, which I wished to lime previous to its being laid down to pasture, and finding that I could not obtain a sufficient quantity of lime for the whole in proper time, I was induced, from observing the effects of fine loam upon the surface of similar soil, even when covered with bent, to try a small quantity of lime on the surface of this fallow, instead of a larger quantity ploughed down in the usual manner. Accordingly, in the autumn, about twenty acres of it were well harrowed in, and then about fifty-six Winchester bushels only, of unslaked lime, were, after being slaked, carefully spread upon each English acre, and immediately well harrowed in. as many pieces of the lime, which had not been fully slaked at first, were gradually reduced to powder by the dews and moisture of the earth, --- to mix these with the soil, the land was again well harrowed in three or four days thereafter. This land was sown in the spring with oats, with white and red clover and rye-grass seeds, and well harrowed without being ploughed again. The crop of oats was good, the plants of grass sufficiently numerous and healthy; and they formed a very fine pasture, which continued good until ploughed some years after for corn.
"About twelve years afterwards I took a lease of the hilly farm of Grubbet, many parts of which, though of an earthly mould tolerably deep, were too steep and elevated to be kept in tillage. As these lands had been much exhausted by cropping, and were full of couch-grass, to destroy that and procure a cover of fine grass, I fallowed them, and laid on the same quantity of lime per acre, then harrowed and sowed oats and grass-seeds in the spring, exactly as in the last mentioned experiment. The oats were a full crop, and the plants of grass abundant. Several of these fields have been now above thirty years in pasture, and are still producing white clover and other fine grasses; no bent or fog has yet appeared upon them. It deserves particular notice that more than treble the quantity of lime was laid upon fields adjoining of a similar soil, but which being fitter for occasional tillage, upon them the lime was ploughed in. These fields were also sown with oats and grass seeds. The latter throve well, and gave a fine pasture the first year; but afterwards the bent spread so fast, that in three years there was more of it than of the finer grasses."
The conclusion which Mr. Dawson draws from his extensive practice in the use of lime and dung deserve the attention of all cultivators of similar land: ---
"1. That animal dung dropped upon coarse benty pasture produces little or no improvement upon them; and that, even when sheep or cattle are confined to a small space, as in the case of folding, their dung ceases to produce any beneficial effects after a few years, whether the land is continued in pasture or brought under the plough.
"2. That even when land of this description is well fallowed and dunged, but not limed, though the dung augments the produce of the subsequent crop of grain, and of grass also for two or three years, its effects thereafter are no longer discernible either upon the one or the other.
"3. That when this land is limed, if the lime is kept upon the surface of the soil, or well mixed with it, and then laid down to pasture, the finer grasses continue in possession of the soil, even in elevated and exposed situations, for a great many years, to the exclusion of bent and fog. In the case of Grubbet-hills, it was observed, that more than thirty years have now elapsed. Besides this, the dung of the animals pastured upon such land adds every year to the luxuriance, and improves the quality of the pasture, and augments the productive powers of the soil when afterwards ploughed for grain; thus producing upon a benty outfield soil effects similar to what are experienced when rich infield lands have been long in pasture, and which are thereby more and more enriched.
"4. That when a large quantity of lime is laid on such land, and ploughed down deep, the same effects will not be produced, whether in respect to the permanent fineness of the pasture, its gradual amelioration by the dung of the animals depastured on it, or its fertility when afterwards in tillage. On the contrary, unless the surface is fully mixed with lime, the coarse grasses will in a few years regain possession of the soil, and the dung thereafter deposited by cattle will not enrich the land for subsequent tillage.
"Lastly, it also appears from what has been stated, that the four-shift husbandry is only proper for very rich land, or in situations where there is a full command of dung; that by far the greatest part of the land of this country requires to be continued in grass two, three, four, or more years, according to its natural poverty; that the objection made to this, viz., the coarse grasses in a few years usurp possession of the soil, must be owing to the surface soil not being sufficiently mixed with lime, the lime having been covered too deep by the plough." --- Farmers Magazine, vol. xiii. P. 69.
Our remarks hitherto have had reference to carbonate of lime in that form of it to which the term lime is exclusively applied by farmers. But there are other substances frequently applied to land which owe their value chiefly to the presence of this mineral. The most important of these is marl, which is a mixture of carbonate of lime with clay, or with clay and sand, and other compounds. When this substance is found in the proximity of, or lying under, sandy or peaty soils, its application in considerable doses is attended with the very best effects. The fen lands of England, the mosses of Lancashire, and sandy soils in Norfolk and elsewhere, have been immensely improved in this way. In Lancashire, marl is carried on the mosses by means of portable railways at the rate of 150 tons, and at a cost of about £3 per acre. In the fens long trenches are dug, and the subjacent marl is thrown out and spread on either side at an expense of 54s. per acre. By this process, often repeated, of claying or marling, as it is variously called, the appearance and character of the fen lands have been totally changed, excellent wheat being now raised where formerly only very inferior oats were produced. As the composition both of peat and of clay marl varies exceedingly, it is always prudent, either by limited experiment or chemical analysis of both substances, to ascertain the effect of their admixture. Lime is always present in those cases which prove most successful; but an overdose does harm.
Under some mosses and fresh-water lakes extensive deposits of shell-marl are frequently found. It contains a larger percentage of lime than clay marl, and must be applied more sparingly.
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