Lime has been often considered as the most efficacious manure for wheat, even more than dung. As long as there is organic matter in the soil, lime acts beneficially, and the richer the land, which does not contain carbonate of lime already, the more powerful the effect of liming. But experience has proved that lime has little effect on poor soils, until they are first manured with animal and vegetable substances. To produce good wheat then, the land should be gradually brought to the proper degree of fertility, by abundant manuring for preparatory crops, which will not suffer from an over-dose of dung, and will leave in the soil a sufficient quantity of humus, intimately blended with it, for a crop of wheat. Clover is a plant which will bear a considerable forcing, and so are beans, and both are an excellent preparation for wheat. The roots left in the ground from a good crop of either, decay slowly, and thus furnish a regular supply of food for the wheat sown in the next season. Potatoes also admit of much forcing, but the necessary loosening of the soil for this crop renders it less fit as a pre paration for wheat. Experience has fully proved that, as a general rule, it is better to sow barley and. clover after potatoes, and let them be succeeded by wheat.
Although wheat thrives best on heavy soils, and without due pre paration produces only scanty and uncertain crops in those which are naturally light and loose, it may be made to give a very good return in soils which would once have been thought fitted only for the growth of rye and oats. But then the texture and composition of these soils must have been greatly improved by judicious tillage and manuring. While the heavy soils are repeatedly ploughed and pulverised to render them mellow, the lighter are rendered more compact by marling, where this can be readily done, by adding composts in which the prin cipal earth is clay, and especially by such plants as have substantial and long roots, by which the soil is kept together, such as clover, lucern, sainfoin, and other grasses. If these plants have been well manured, and cover the ground well, keeping in the moisture, the soil will have become sufficiently compact to bear wheat. One ploughing is then quite sufficient, and if a heavy land-presser is made to follow two ploughs and press in the furrows, so as to leave deep smooth drills eight or nine inches apart, in which seed can find a solid bed, there will be every probability of a good crop. of wheat, which will come up in regular rows, the roots being at such a depth as to run no risk of wanting moisture till the stem has arisen to its full height, and the ear is formed : a few showers at that critical time will make the grain swell, and insure a good crop.
On some soils it may not be judicious to attempt to sow wheat; but these are the poorest loose sands, which naturally would bear only oats and buckwheat ; on these, unless they can be abundantly marled, it is much better to sow rye. When wheat is sown on light soils in good heart, it grows vigorously in spring, if it has not been injured by the frost, which is very apt to raise up the roots and throw them out of the ground. The driving of sheep over the field presses the roots into the ground, and prevents this throwing out ; but a vigorous growth of straw is not always a sure sign of a good crop at harvest, as many farmers know by sad experience : what would he advisable in heavy soils is not always so in lighter. A heavy rolling in spring after a light harrowing is very useful at a time when the surface is moist. It closes the pores and checks the evaporation : and the tighter the surface can be made the better the chance there is of a fair crop. The Norfolk rotation, as it is generally called, in which wheat is sown after clover, is the only one well adapted for wheat on light soils. The manure having been put abundantly for the turnips, and the land being freed from weeds, the barley which follows is generally a good crop; the clover, which is sown in this, is trodden in the reaping and carry ing of the barley : and there is only one ploughing from the time the barley is sown to the sowing of the wheat. If this be dibbled on the turned award of the clover, the land will receive another treading by the dibblers, the seed will be regularly deposited at a proper depth, and no preparation of light land can be more likely to produce good wheat. On heavy soils the process must be varied; the surface, instead of being rendered more compact, will often be so bound as to require to be stirred by harrowing or hoeing before the wheat plant can properly tiller. If a farmer is anxious to have good crops of wheat, he must not rest satisfied after he has ploughed, manured, and sown : he must watch the growth of this important crop daily, and use the means which experience and observation have suggested to assist the growth and to remove the causes of failure.
In either case it is of importance to sow the proper quantity of seed per acre in rows far enough apart. One bushel per acre is enough on well-cultivated soils—two bushels are not too much where there is liability to loss by water, wireworm, and weather. If sown by drill from 10 to 12 inches is a proper interval between the rows.