By dung we are limited to quantity of it we can procure, which in most places is too scanty.
But by tillage we can enlarge our field of subterranean pasture without limitation, though the external surface of it be confined within narrow bounds.
Tillage may extend the earth's internal superficies, in proportion to the division of its parts, and as division is infinite, so may that superficies be.
Every time the earth is broken by any sort of tillage or division there must arise some new superficies of the broken parts which never has been open before : for when the parts of earth are once united and incorporated together, it is morally impossible that they, or any of them, should be broken again, only in the same places ; for to do that, such parts must have again the same numerical figures and dimensions they had before such breaking, which even by an infinite division could never be likely to happen.
* "Neque enim aliud est colere quam resolvere, et fermentare terram." - Columella.
And since the artificial pasture of plants is made and increased by pulverisation, it is no matter whether it be by ther ferment of dung, the attrition of the plough, the contusion of the roller, or by any other instrument or means whatsoever, except by fire, which carries away all the cement of that which is burned.
As the letters of a distich, cut out and mixed, if they should be thrown up ever so often, would never be likely to fall into the same order and position with one another, so as to recompose the same distich.
Although the internal superficies may have been drained by a preceding crop, and the next ploughing may move many of the before divided parts without new breaking them, yet such as are new broken, have, at such places where they are so broken, a new superficies, which never was or did exist before ; because we cannot reasonably suppose that any of those parts can have in all places (if in any places), the same figures and dimensions twice.
For as the matter is divisible, ad infinitum, the places or lines whereat it is so divisible must be, in relation to number, infinite, that is to say, without number ; and must have at every division superficies of parts of infinite variety* in figure and dimensions.
And because it is morally impossible the same figure and dimensions should happen twice to any one part, we need not wonder how the earth, every time of tilling, should afford a new internal superficies (or artificial pasture), and that the tilled soil has in it an inexhaustible fund, which by a sufficient division (being capable of an infinite one) may be produced.
* Their variety is such, that it is next to impossible any two pieces or clods in a thousand acres of tilled ground should have the same figure and equal dimensions ; or that any piece should exactly tally with any other, except with that from whence it was broken off.
Tillage (as well as dung) is beneficial to all sorts of land*. Light land being naturally hollow, has larger pores, which are the cause of its lightness. This, when it is by any means sufficiently divided, the parts being brought nearer together, becomes for a time , bulk for bulk, heavier ; i. e., the same quantity will be contained in less room, and so is made to partake of the nature and benefits of strong land, viz., to keep out too much heat and cold, and the like.
But strong land being naturally less porous, is made for a time lighter (as well as richer) by a good division ; the separation of its parts makes it more porous, and causes it to take up more room than it does in its natural state, and then it partakes of all the benefits of lighter land.
When strong land is ploughed, and not sufficiently, so that the parts remain gross, it is said to be rough, and it has not the benefit of tillage : because most of the artificial powers (or interstices) are too large, and then in partakes of the inconveniences of the hollow land untilled.
*It is of late fully proved, by the experience of many farmers, that two or three additional ploughings will supply the place of dung, even in the old husbandry, if they be performed at proper seasons ; and the hiring price of three ploughings, after land has been thrice ploughed before, is but twelve shillings, whereas a dunging will cost three pounds. This was accidentally discovered in my neighbourhood, by the practice of a poor farmer, who, when he had prepared his land for barley, and could not procure seed to sow it, ploughed it on till wheat-seed time, and (by means of such additional ploughing) without dung, had so good a crop of wheat, that it was judged to be worth more than the inheritance of the land it grew on.
The same effects follow when they prepare land for turnips, since they are come in fashion, and sow them several times upon several ploughings, the fly as often taking them off ; they have from such extraordinary tillage a good crop of wheat, instead of the lost turnips, without the help of dung ; hence double ploughing is now become frequent in this country.
The reason why land is enriched by lying long unploughed is, that so very few vegetables are carried off it, very little being produced, the exhaustion is less than what is added to the atmosphere, cattle, &c. But when it is ploughed, a vastly greater quantity of vegetables is produced and carried off, more than by the hold husbandry is returned to it.
For when the light land is ploughed but once, that is not sufficient to diminish its natural hollowness (or pores), and , for want of more tillage, the parts into which it is divided, by that once (or perhaps twice) ploughing, remain too large, and consequently the artificial pores are large also and in that respect are like the ill-tilled strong land.
Light land having naturally less internal superficies, seems to require the more tillage* or dung to enrich it ; as when the poor, hollow, thin down shave their upper part (which is the best) burned, whereby all (except a caput mortuum or terra damnata is carried away, yet the salts of this spread upon that barren part of the staple which is unburned, divide it into so very minute particles, that their pasture will nourish two or three good crops of corn : but then the plough, even with a considerable quantity of dung, is never able afterwards to make a division equal to what those salts have done, and therefore such burned land remains barren.
* As for puffy land, which naturally swells up instead of subsiding, though its hollowness is much abated by tillage, yet is thought little better than barren land, and unprofitable for corn. But what we usually call light land, is only comparatively so, in respect of that which is heavier and stronger. And this sort of light land becomes much lighter by being ill tilled ; the unbroken pieces of turf underneath, undissolved, forming large cavities, increase its hollowness, and consequently its lightness. I have often know this sort of land despised by its owners, who feared to give it due tillage, which they thought would make it so light that the wind would blow it away ; but whenever such has been thoroughly, tilled, it never failed to become much stronger than before ; and considering that it is tilled with less expense than very strong land, it is, for several sorts of corn, found to be more profitable than land of greater strength and richness, that is more difficult to be tilled.
And I am apt to think that this sort of light land acquires more cement by having its external superficies often changed and exposed to the dews and other benefits of the atmosphere, as well as by the increase of its internal superficies, which is, the surface of all the divided parts of earth or the pasture of plants ; the one being augmented by the other ; i. e., that into the more parts the earth is broken, the more cement will it obtain from the sulphur which is brought by the dews.
Artificial pores cannot be too small, because roots may the more easily enter the soil that has them, quite contrary to natural pores ; for these may be, and generally are, too small and too hard for the entrance of all weak roots, and for the free entrance of strong roots.
Insufficient tillage leaves strong land with its natural pores too small, and its artificial ones too large. It leaves light land with its natural and artificial pores both too large. Pores that are too small in hard ground, will not easily permit roots to enter them. Pores that are too large in any sort of land, can be of little other use to roots, but only to give them passage to other cavities more proper for them, and if in any place the lie open to the air, they are dried up and spoiled before they reach them.
For fibrous roots (which alone maintain the plant, the other roots serving only for receiving the chyle from them, and conveying it to the stem) can take in no nourishment from any cavity, unless they come into contact with, and press against all the superficies of that cavity which includes them ; for it dispenses the food to their lacteals by such pressure only. But a fibrous root is not so pressed by the superficies of a cavity whose diameter is greater than that of the root.
The surfaces of great clods form declivities on every side of them, and large cavities, which are as sinks to convey what rain and dew bring too quickly downwards to below the ploughed part.
The first and second ploughings, with common ploughs, scarcely deserve the name of tillage ; they rather serve to prepare the land for tillage. The third, fourth, and every subsequent ploughing, may be of more benefit and less expense than any of the preceding ones. But the last ploughings will be more advantageously performed by way of hoeing, as in the following chapters will appear. For the finer land is by tillage, the richer will it become, and the more plants it will maintain.
It has been often observed that when part of a ground has been better tilled than the rest, and the whole ground constantly managed alike, afterwards for six or seven years successively, this part that was but once better tilled, always produced a better crop than the rest, and the difference remained very visible every harvest.
One part being once made finer, the dews did more enrich it ; for they penetrate within, and beyond the superficies, whereto the roots are able to enter. The fine parts of the earth are impregnated throughout their whole substance with some of the riches carried in by the dews, and there deposited ; until by new tillage, the insides of those fine parts become superficies ; and as the corn drains them they are again supplied as before : but the rough large parts cannot have that benefit, the dews not penetrating to their centres, they remain poorer. Minus habentibus minus datur et vice versa.
I think nothing can be said more strongly to confirm the truth of this, than what is related by the authors quoted by Mr. Evelyn*. To this effect, viz.,
" Take of the most barren earth you can find, pulverise it well, and expose it abroad for a year, incessantly agitated, (that is, stirred often), it will become so fertile as to receive an exotic plant from the furthest Indies, and to cause all vegetables to prosper in the most exalted degree, and to bear their fruit as kindly with us, as in the natural climates."
This artificial dust**, he says, will entertain plants which refuse
* In page 17, 18, and 19, of this Phil. Discourse of Earth.
** Though it may be impossible for the plough to reduce the whole staple into so fine powder, yet the more internal superficies it makes, the more dust will be made by the atmosphere in proportion ; and great clods perhaps are of no use to plants, but by that dust they let fall, being thence extricated by the insensible ferment of the nitrous air ; and the surfaces of this artificial dust must receive such operations from the air, before the utmost fertility be obtained.
dung andother violent applications, and that it has a more nutritive power than any artificial dungs or compost whatsoever : and further, that by this toil of pulverising " it is found that soil may be so strangely altered from its former nature as to render the harsh and most uncivil clay* obsequious to the husbandman, and to bring forth roots and plant, which otherwise require the lightest and hollowest mould**."
It is to be supposed that the Indian plants had their due degrees of heat and moisture given them, and I should not choose to bestow this toil upon the poorest of earth, in a field or garden, though that be the most sure wherein to make the experiment.
This is the most proper trail of the effect of pulverisation by pounding and grinding ; but land may be so barren, that plough or spade may not be sufficient to pulverise it to that degree which is necessary to give it the same fertility, that pounding in a mortar, or grinding betwixt marbles (as colours are ground), can.
I never myself tried this way of pounding or grinding, because impracticable in the fields.
* But I take harsh uncivil clay to be the lest profitable of any to keep in tillage.
** To this dust, namque hoc imitamur arando ought to be applied, and not to putre solum, which itself needs tillage as well as strong land ; but it seems the ancients did not observe the difference between natural pores (or hollowness) and artificial ones, though it is very great, as is shown in chap. of Pasture of Plants ; it is easier indeed to imitate this artificial dust in hollow than in strong land.
But I have had the experience of a multitude of instances, which confirm it so far, that I am in no doubt that and soil* (be it rich or poor) can ever be made too fine for tillage.
According to some, this rule is only general, and not universal ; for say they, there is a sort of binding gravel, that when it is made fine, will, by a sudden dash of rain, run together like metal ; and I have seen the same accident in a particular sort of white land, but this very rarely happens to the latter, I never knew it above once, and that was after barley was sown on it ; the hardness was only like a very thin ice upon the surface, which was some hindrance to the coming up of the barley, until the harrows going over it once or twice broke that ice or crust, and then in come up very well.
I never had any other sort of land liable to this misfortune ; therefore can say nothing to the gravel in that case, nor how deep the constipation may reach in it, nor what remedy is most proper to prevent the ill consequence of it ; but if ther should be two or three exceptions out of one thousand seventy-nine millions one thousand and sixty different sorts of earth (see Mr. Evelyn's Terra, p. 2), it will be no great matter.
But I think these are no real exceptions against any degree of pulverising ; for they only show, that some sorts of land, though very few, are subject by accident to lose too soon their
pulverisation : and if the fineness were no benefit to that land, such loss of it would be no injury to it.
* Land that is too hollow and light having no cement to join its parts together, though in nature they are capable of infinite division, yet in practice the plough cannot divide them to any purpose, unless they were first joined, but glides through without breaking them ; being more like to the primary particles of water against the plough, which are broken by no force, than to earth ; it may be moved but not broken by tillage, and therefore ought not be reputed arable ; nor does it indeed deserve the name of land, but as the desert sands of Libya, to distinguish it from sea.
For it is without dispute, that one cubical foot of this minute powder, may have more internal superficies than a thousand cubical feet of the same, or any other earth tilled in the common manner ; and I believe no two arable earths in the world do exceed one another in their natural richness twenty times ; that is, one cubical foot of the richest, is not able to produce an equal quantity of vegetables, cęteris paribus, to twenty cubical feet of the poorest ; therefore, it is not strange that the poorest, when by pulverising it has obtained one hundred times the internal superficies of the rich untilled land, should exceed it in fertility. Or, if a foot of the poorest were made to have twenty times the superficies of a foot of such rich land, the poorest might produce an equal quantity of vegetables with the rich*. Besides there is another extraordinary advantage when a soil has a large internal superficies in a very little compass ; for then the roots of plants in it are better supplied with nourishment, being nearer to them on all sides within reach, than it can be when the soil is less fine, as in common tillage ; and the roots in the one must extend much further than in the other, to reach an equal quantity of nourishment : they must range and fill perhaps about twenty times more space to collect the same quantity of food.
* And very poor land well pulverised, will produce better corn than very rich will do, without manure or tillage. The experiment may be made by paring off the turf, and setting corn in the whole ground that is very rich ; and that will show how much the natural pasture of the rich is inferior to the artificial pasture of the poor land.
But then the poor must have this proportion of excess of internal superficies continued to it, during the whole time of their growth, which cannot be done without frequently-repeated divisions of the soil by hoeing or manure ; else it might require forty times the internal superficies, at the time of sowing, to keep twenty times the internal superficies of the rich till harvest : for although the rich is continually losing some of its artificial pasture, as well as the poor, yet by losing this equally, they will draw nearer and nearer to the first inequality of their natural pasture.
But poor land, being lighter, has this advantage, that it being more friable than the strong, requires less labour to pulverise it, and therefore the expense of it is much less than in proportion to the excess of poorness of its internal superficies.
But in this fine soil the most weak and tender roots have free passage to the utmost of their extend, and have also an easy, due, and equal pressure everywhere, as in water.
Hard ground makes a too great resistance, as air makes a too little resistance, to the superficies of roots.
Farmers, just when they have brought their land into a condition fit to be further tilled to much greater advantage, leave off, supposing the soil to be fine enough, when with the help of harrows they can cover the seed ; and afterwards with a roller they break the clods, to the end that if a crop succeed, they may be able to mow it without being hindered by those clods. By what I could ever find, this instrument, called a roller, is seldom beneficial to good husbands : it rather untills the land, and anticipates the subsiding of the ground, which in strong land happens too soon of itself*.
* This injury the roller does, is only when it is used to press down the earth after the seed in sown, and is the greater if land be moist ; but the rolling of it in dry weather, when it is to be immediately ploughed up again, is the most speedy way to pulverise the soil, and the harrow is then very useful in pulling up the clods, to the end that the roller may the better come at them to crush them.
But more to blame are they, who neglect to give their land due ploughing, trusting to the harrow to make it fine ; and when they have thrown in their seed, go over it twenty times with the harrows², until the horses have trodden it almost as hard as a highway, which in moist weather spoils the crop ; but on the contrary, the very horses, when the earth is moist, ought all to tread in the furrows only, as in ploughing with a hoe-plough they always do, when they use it instead of a common plough.
* Nam veteres Romani dixerunt male subactum Agrum qui satis frugibus Oceandus sit.
Sed ut compluribus iterationibus sic resolvatur Vervactum in pulverem, ut nullem vel exiguam desideret occationem cum seminaverimus. - Col. lib. 2. cap. 4.