TILLAGE, applied to arable land, is the stirring and preparing of the surface of the soil, eo as to render it fit for the vegetation of the seeds committed to it : its object also is the destruction of noxious weeds.
Tho whole art of cultivation consists in tillage and manuring, and the profit of the husbandman depends on the perfection of the tillage and the economy of labour in producing the effect. A defect in tillage will cause a great deficiency in the drops in ordinary years. To ensure good crops, the soil should be in such a state that the rains and dews may readily be diffused through it, without giving it a wet appearance, or evaporating too rapidly. It requires great knowledge and experi ence to give any particular soil the exact portion of tillage which is suited to it. A fine garden-tilth, as It is called, is the most perfect for light soils which have been long cultivated and manured ; when they can be brought to such a state that after continued rains the sur face dries without forming a cruet, and crumbles of its own accord, the tillage has been good; and the deeper this soil is stirred, the more it will produce : but where clay abounds in the soil, which in dry weetther can be readily pulverised by crushing the dry clods, and be reduced to the finest powder, too much tillage may do more harm than good. The fine clay is soon converted into mud at the surface by the least rain, because it Is not sufficiently porous to let the water through it ; it dries into a hard cruet, which effectually precludes the access of air, and consequently stops the vegetation of the aced. It is only by abundant manuring with organic matter, especially of animal origin, that this natural tendency in clays to cohere can be overcome ; and until this is effected it is beet to stir clay soils as deep as possible by means of subsoil-ploughs, but they should not be pulverised so that the water cannot run down between the lumps and clods, and especi ally the surface should be left in such a state of roughness that heavy rains cannot cover it with a coat of mud. The clods which are left on the °urine° imbibe the moisture more gradually, and in drying fall to pieces, by which the young plants are invigorated, and, as it were, moulded up. This is particularly the case in winter after a frost, as all clay-land farmers are well aware. It is very easily ascertained whether a soil will bear much tillage or not. It is only necessary to try some of it in a large pot or box ; make the surface very fine by breaking the clods, then water it abundantly, and let it dry in the sun; if a crust is formed in drying, that soil will not bear too much harrowing and palveriaing, and should be left in a moderately rough state after sowing or drilling the seed; but if, after it dries, the sur face is loose and porous, then the finer the tillage the better the aced will vegetate. The whole depends on the ready admission of air or its exclusion. When grass-seeds are sown, the surface should be well pulverised ; but this cannot be safely dons if the soil is apt to rim together when much rain falls soon after the seed is sown. Some liko brans, will force their way through a very hard surface; but small seeds are too weak to do so, and their growth is entirely stopped by the least crust on the surface. Besides the preparatory
tillage of the soil before sowing the seed, there is a great advantage in the stirring of it as the plants are growing. On this depends all the merit of the row-culture for every kind of plant, especially those which have esculent roots or extensive foliage, and which are chiefly cultivated for the sustenance of cattle. The effect of deep tillage is here most remarkable. If rows of turnips or cabbages be sown at such a distance that a small plough or other stirring implement can be used between them, and the intervals bo stirred more or less, and at different depths, it will be found that the deeper and more frequent the tillage, until the foliage covers the whole interval or the bulbs swell to a great size, the heavier and more abundant the produce will be. It was this which led Tull, the father of drill husbandry, to the conclusion that tillage was all that the soil required to maintain perpetual fertility. As tillage can be increased by mechanical con trivances where labourers are scarce, whereas the supply of manure must generally be limited, it follows that, as a general rule, the land should be well and deeply tilled, duo attention being paid to the nature of the soil and its property of retaining or transmitting moisture. Very loose sands should not be much stirred until they are consolidated by the admixturo of marl, clay, chalk, or well-rotten dung; but in all cases the manure should be mixed as intimately as possible with the soil, and as deep as the tillage has gone, not including the stirring of the subsoil ; for the roots will always pene trate thus far and find the nourishment which they require. Those plants which throw out roots from the bottom of the stem, as wheat, barley, and oats, require the surface to be most pulverised and enriched to allow these roots to spread, and Mr. 'Smith of Lois Weedon has found that where land is clayey and contains the mineral food of plants, sufficient tillage between rows of wheat is all that is needed for constant cropping, or taking wheat after wheat annually from the same field. Under ordinary culture, however, of this crop a spring tillage is highly advantsgeous, which can only be given when the seed has been deposited in rows by drilling or in patches by dibbling. This last method is found to give much finer crops, from the circumstance that the hoe not only loosens the earth between the rows, but also between the different patches of the growing corn, by which the coronal roots are strengthened and the tillering of the stuns so much encouraged, that it is not uncommon to see twenty, thirty, or more strong stems all bearing fine ears arising from one tuft of plants, the produce of one or more seeds, whose roots are matted together and send out fibres in every direction. The crowding of several plants does not prevent their growth, provided the fibres can spread around in a rich mellow soil, well pulverised, and admitting the air and moisture readily.