OCR Text |
Show SOIL PARTICLES Measurements recently made at the station show, says M. D. Thomas, of the U. A. C. Experiment Station, that if all the particles in a pound of soil could be flattened out so that each one exposed its own natural surafce, the rear covered would range from about one-tenth acre in the case of a sandy loam to over three acres in the case of a heavy clay. Since an acre-foot of soil weighs about four million pounds, the amount of solid surface in the immediate feeding feed-ing zone of plants growing on an acre of heavy clay is nearly one-J one-J fourth of the area of the state of Utah. This colossal exposure is the secret of the soils power to sustain vegetation. By it, a reserve supply of moisture is held for weeks or even months, to be used as the needs of the plant demand. By it, the mineral min-eral foods of the plant, the lime, the phosphorus, the potash, and the nitrogen ni-trogen are rendered available in sufficient suf-ficient quantity to nourish the plant. The amount of surface in a given case determines how heavy the soil is, and its disposition determines how the land should be tilled |