Soils Built Wholly Or Partly By The Wind

Soils built wholly or in part by wind are not uncommon. In arid regions, along the sea coast and near the shores of the Great Lakes, the drifting sands often cover and ruin valuable soils. Some of the most productive farm soils in this country were made, and are still being made, by wind. A noted example is the Palouse region of eastern Washington, eastern Oregon and northern Idaho. Here the land is a succession of rounded knolls and hills, which are sometimes several hundred feet high and are a rich, black, basaltic ash to the bottom. The native Indians account for the hills in a legend. They say that at one time all this region was a level prairie of marvellous fertility. Wonderful crops of maize were raised upon it by the red men. One evil day they heard that the white men were coming. Knowing by repute the white man's greed, the Indians went to work to gather the precious soil into huge heaps, preparatory to carrying it away into the mountains, beyond the grasp of the avaricious whites. But the white men came before the soil could be carried away, took it for their grain fields, and it has been in heaps ever since. The more prosaic geologist, however, says that these fertile hills were made almost entirely by wind, assisted by erosion.

In parts of California, Oregon, Washington, and Wyoming, the clay less "dust soil" becomes cracked and loosened in dry weather and is carried away by the wind in dense clouds, banking up like snow behind rocks and bushes. Recall, also, the stories of caravans in the desert being overwhelmed by sandstorms. There are numerous records of large quantities of soil being carried over a thousand miles by wind. Even where the soil has been made mostly by other agencies, wind contributes something to it. Fine soil, leaves, chaff and dust are swept over the hill crest and deposited on the leeward slope. The amount of soil that is made and transported by wind, in the form of dust, must amount to an appreciable quantity in the course of a year. The slope opposite to that of the prevailing wind is usually less abrupt than the other, because so much soil material has been deposited there by the wind. Still another way in which wind assists in making soil is by blowing fine particles of sharp sand and dust against the rocks and so wearing them away.

At first thought it would seem that the result of this would be very insignificant, but in reality it is often quite important. In arid parts of the United States and elsewhere, the millions and millions of soil grains blown against cliffs and rocks leave a striking testimony to their abrasive power. In a surprisingly short time rough corners are worn smooth, great boulders are undermined, hollows are scoured out, and sometimes large, erect rocks are completely filed off near the base, where the wind-blown sand is thickest, and fall over. The "Mushroom Rocks" of Wyoming are a notable example. In humid sections, the filing of rocks by blown sand is less conspicuous, except near the sea-coast. The windows of houses near the coast are roughened and sometimes eaten through by the natural sandblast.

THE SOIL TEEMS WITH LIFE

Countless tiny organisms, visible only to the eye behind a microscope, are constantly at work, changing, breaking down, building up. Some are beneficial, some are harmful, some are harmless. How many kinds there are, and what part each plays in the complex operation of soil building, nobody knows, for the science of bacteriology is yet at its beginning. Every farm presents many phases of soil building and soil wasting. The farmer should observe the various agencies at work upon his land, and turn them to his own profit. He should remember that the soil is not dead, but alive; that it is constantly swept by winds, worn and transported by waters, broken and refined by frost and air, loosened and enriched by plants and animals, and all the while creeping nearer and nearer to a level.