A young growing animal, whether a child or a colt, that is kept on food which lacks bone-earth, (phosphate of lime,) will have soft cartilaginous bones. Nature cannot substitute iron or any other mineral in the animal system, out of which to form hard strong bones; nor can any other mineral in the soil perform the peculiar function assigned to silica in the vital economy of cereal plants. To protect the living germs in the seeds of wheat, corn, oats, rye, barley, &c. the cuticle or bran of these seeds contains considerable flint. The same is true of chaff.
The question naturally arises,—How is the farmer to increase the quantity of soluble silica or flint in his soil? This is a question of the highest practical importance. There are three principal ways in which the object named may be attained. First, by keeping fewer acres under the plough. Land in pasture, if well managed, will gain its fertility, and in the process accumulate soluble silica in the surface soil. In this way more wheat and surer crops may be made by cultivating a field in wheat two years than four or six. If the field in the mean time be devoted to wool-growing, butter or cheese-making, or to stock-raising, particular care must be taken to make great crops of grass or clover to grow on the land, and have all the manure, both solid and liquid, applied to its surface.
There are many counties in England that yield an average of thirty-two bushels of wheat per acre for ten crops in succession. There are but few of the old counties in the United States which average the half of that quantity: and yet America has greater agricultural capabilities than that of Great Britain.
Another way to increase soluble silica in the soil, is to grow such crops, in rotation with wheat culture, as will best prevent the loss of dissolved flint, at any time by leaching and washing, through the agency of rain water. This remark is intended to apply more particularly to those large districts devoted to cotton and tobacco culture, plants that take up no considerable amount of silica, and which by the constant stirring of the earth, and the clean tillage which they demand, favor the leaching of the soil. To keep too much of a plantation of these crops, is to lessen its capabilities for producing good crops of corn, wheat, and barley, at a small expense. Corn plants, well managed, will extract more pounds of silica in three or six months from the soil, than any other. As not an ounce of this mineral is needed in the animal economy of man or beast, it can all be composted in cornstalks, blades, and cobs, or in the dung and urine derived from corn, and be finally reorganized in the stems of wheat plants. Corn culture and wheat culture, if skilfully and scientifically conducted, go admirably together. Of the two, more bread, more meat, and more money can be made from the corn than from the wheat plant in this country. But so soon as what is called "high farming" in England, shall be popular in the United States, the crops both of wheat and corn grown here will demonstrate how little we appreciate the vast superiority of our climate for the economical feeding and clothing of the human family, over that of our "mother country." In several counties in England, it takes from twelve to fourteen months to make a crop of wheat, after the seed is put into the ground. At or near the first of December, 1847, Mr. M.B. Moore, of Augusta, Ga., sowed a bushel of seed wheat on an acre and a half of ground, which gave him over thirty bushels by the middle of May following. This ground was then ploughed, and a fine crop of hay made and cut in July. After this, a good crop of peas was raised, and harvested in October, before it was time to seed with wheat again, as was done. While the mean temperature of England is so low, that corn plants will not ripen, in Georgia one can grow a crop of wheat in the winter, and nearly two crops of corn in succession in the summer and autumn, before it is time to sow wheat again. No writer, to my knowledge, has done full justice to the vast agricultural resources of the southern portion of the American confederacy. But there is much of its soil which is not rich in the elements of bread. Nothing but the careful study of these elements, and of the natural laws by which they are governed, can remedy defects in wheat culture anywhere, but especially on very poor land.
All alkaline minerals, such as potash, soda, lime, ammonia, and magnesia, hasten the solution of the several insoluble compounds of silica in the soil. This fact should be remembered by every farmer. To undertake an explanation of the various ways in which alkalies, oxides, and acids act and re-act upon each other in the surface of the earth, when subject to tillage, would be out of place in this outline view of wheat-growing in the United States. I may state the fact, however, as ascertained by many analyses, that a cubic foot of good wheat soil in the valley of the Genesee, contains twenty times more lime than do the poorest soils in South Carolina and Georgia. The quantity of gypsum, bone-earth, and magnesia, available as food for plants, varies in an equal degree. Not only lime, but phosphoric acid, potash, and magnesia are lacking in most soils, if one desires to raise a large crop of wheat, and have the seeds of the grain weigh as much as the straw. In a number of the specimens of wheat analyzed by Prof. Way, when cut close to the roots, the dry wheat outweighed the dry straw.
Having secured the growth of a bright, hard, glassy stem, the next thing is to develop a long, well-filled ear. To this end, available ammonia or nitrogen, phosphorus, potash, and magnesia are indispensable. Ammonia (spirits of hartshorn) is necessary to aid in forming the combustible part of the seed. The other ingredients named are required to assist in making the incombustible part of the grain. In 100 parts of the ash of wheat, there are the following substances, viz.:—
| Silica | 2.28 |
| Phosphoric acid | 45.73 |
| Sulphuric acid | 0.32 |
| Lime | 2.06 |
| Magnesia | 10.94 |
| Peroxide of iron | 2.04 |
| Potash | 32.24 |
| Soda | 4.06 |
| Chloride of sodium | 0.27 |
| Total | 99.94 |
The quantity of ash in wheat varies from 1¼ to 2½ per cent.; the average is about 1.69. The amount of phosphoric acid in any given quantity of the ash of wheat varies from forty to fifty per cent. of the same.
Seeds that have a thick cuticle or bran, and little gluten, contain a smaller per centage of phosphoric acid, and more silica. About one-third of the ash is potash; in nearly all cases magnesia varies from nine to fourteen per cent.; lime from one and a half to six per cent. Peroxide of iron is seldom as abundant as in the ash above given, and the same is true of soda. Chloride of sodium is common salt, and exists in a small quantity. Salt is beginning to be much used as a fertilizer on wheat lands in western New York. It operates indirectly to increase the crop.
The following may be taken as about the average composition of the ash of wheat-straw. It is "Specimen No. 40," in the tables of Prof. Way, and I copy verbatim all that is said upon the subject: [Soil, sandy; subsoil, stone and clay; geological formation, silurian; drained; eight years in tillage; crop, after carrots, twenty tons per acre; tilled December, 1845; heavy crop; mown, August 12th; carried, August 20th; estimated yield, forty-two bushels per acre; straw long, grain good, weight sixty-two pounds to the bushel.] Length of straw, forty-two inches.