SOIL. Soil is distinguished from earth in that it contains a greater quantity of organic vegetable matter than the sands, gravels and' clays, which constitute so large a portion of the upper surface of the earth's crust. The earths originally were composed of the detritus or decom position of the various rocks. Until this wear ing away and decomposition became partial at least no vegetation could subsist. This is pri marily brought about by the action of the oxygen, of the air, by the action of rain, running water, floods, but more generally by the grinding power of glacial action which at some time seems to have been present on nearly every portion of the earth's surface. Upon the relations of Geology to Agriculture—Hon. James Shaw, in an address to the Northern Illinois Horticultural Society, truly said: Soils are derived from the decomposi tion of the rocks. The silent processes of nature, to-day, as in past geologic ages, are grinding rocks into soils, and re-cementing and hardening soils into stratified rocks. There was a time when the earth was, indeed, rock-ribbed; but atmos pheric and chemical agencies and aqueous forces kept in constant action, processes of slow decay, and the soils were gradually formed as precipi tates and sediments in ancient geologic seas. We all know the old proverbs about the constant dropping that wears away the stone, and the file of time that wears and makes no noise; but few realize how important a part these peaceful agen cies have taken in the creation of the present order of things. The frost and the rain, and other like agencies and energies of nature, are all powerful to bring about the mightiest results. If undisturbed by mechanical forces, the superficial t clays, loams, sands, subsoils and soils covering the underlying rocks would be nothing but the residuum left after the removal by the percola tion of the water of the more soluble portions of the rocky ledges, which had decayed. The soil' would be in situ. It would bear a close resem blance to the rocks from which. derived. The geologist, by an examination of the rocks, could tell the nature of the soil with which they were covered, and, by an examination of the soils, could designate what rocks they concealed. Pri marily, all soils are derived from fire rocks; sec ondarily, many of them are derived from water rocks. The first resemble, in composition, the primary rocks; the second, having first been granites, then, by the decay of the granites and the transportation of water, becoming stratified rocks, whose decay and chemical' combinations, and separations, separated and assorted by the elements, oftentimes do not resemble the first at all. The general proposition is, however, true,.
that rocks differ from each other, and soils also resemble the rocks from which they are derived. In small patches, and to a limited extent, this is true of the soils of the West. The alluvial bottoms of our riven: are generally sedi mentary soils, somethues hungry sandy soils, but often black, fat, sedimentary deposits. The latter produces great crops of Indian corn, when dry enough to cultivate; but, when low and wet. it grows heavy crops of the coarse prairie and slough grasses. But the most marked illustra tion of the proposition under discussion, may be noticed in localities underlaid by the Cincinnati shales. Here the soil and subsoil, if undisturbed, is a close grained, finely comminuted, buff or straw-colored clay. It is so compact and tenacious that it becomes water-soaked, and has not the power to rapidly absorb surplus moisture. The best soil is the formation known as Loess, by western geologists. It caps, and in most cases, makes up a large proportion of the bluff ranges along the Missisippi river, and some of the inter nal streams in that part of Illinois; it sometimes extends back for some miles from the bluffs into the interior; but, in the latter case, it is seldom pure, but is mixed with other sands and clays.
It is white, buff-colored silt, of extreme fineness of texture, where purely developed; but it often consists of marshy, sandy deposits, and various mixtures and clayey combinations—for vines and deep-rooted trees no better deposits exist in the State. It owes its origin to the silt washed up by broad sea-like lakes and wide lake-like rivers. It affords little resistance to the penetrating root lets of trees, is well-drained, and is unsurpassed, either for wheat, fruits, grapes or vegetables. The foregoing remark,s are based ou the arg-u ment that soils are derived from the decay of the underlying rocks. An examination of the soils of the prairie region of the West, however, will soon convince any one that this statement, as a matter of fact, is true to only a limited extent; it will do for fragmentary patches and driftless regions. Over .wide stretches of country the decay of the rocks has not formed the soils covering them. Transportation of soils, a uni versal mingling of materials derived from widely different sources, is a fact susceptible of easy demonstration. That tremendous force which tore the bowlders from their parent outcrops in the clistant Lake Superior regions, and chifted them along on their southward journey, which grooved and planed the surface of the solid rocks, which strewed, for hundreds of miles, beds of clay and sand and gravel, whether floes and bergs of ice, borne by winds and currents loaded with stones and detrital matter, or strong water currents miogling and weaiing the moving beds of abraded materials, or the procession of the slow, silent. all-powerful glaciers, grinding the solid stones into soils, as wheat is ground to flour between the upper and nether mffi-stones, whe ther one, or all these causes combined, it mingled. mixed, transported and formed the soils to such an extent as to well nigh destroy their separate and characteristictic origin, and greatly increase the difficulty of their proper classification. In attempting to classify soils and earths thus made and mingled there is no end to the distinctions and divisions. Soils are light or heavy, warm or cold, dry or wet, compact or porous, fine or coarse, hungry, leachy, loamy, sour, sweet, clayey, sandy, limy, marly, and various combin ations of these too numerous to mention. Silica, or the earth of flints; alumina, lime, magnesia, potash, and various salts and metalloid com pounds unite in various combinations to make up these soils. The humus, which gives rich ness aud blackness of color, is chiefly derived from successive growths and decays of grasses and other vegetations. The question as to what soils will produce and mature good and constant crops depends not only upon the nature of the soils themselves, but also upon climatic influ ences, and upon the nature and properties of subsoils. If the subsoil is gravelly, marly, por ous, leachy, sandy, or of such a texture as not to retain water too easily, altuost any soil will pro duce trees and fruits. But, if a hardpan, or other tough, impervious clay, happens to be the subsoil, so as to retain the surplus moisture, the • best soil in the world unless a very deep one, will not respond to a liberal cultivation, with a generous supply of good, vigorous, healthy, and sure crops. The best soils for wheat are dry, firm, but easily disintegrable, and rather com pact soils, such as contain a good proportion of lime and clay. The best Indian corn is raised upon the deep humus, prairie soils and river bot toms of the West, but a good wheat soil is also. a good corn soil if the summer is long enough to. ripen the crop. In this connection the classifica tion of soils, their composition and their organic and inorganic matter will give a good idea of what constitutes soils for cereal crops. A loess. soil, as heretofore stated, is admirable for the grains, grasses, and for fruit. The classification of Boussingault is excellent and is as follows:.