Some properties of the soil solution and the colloids in certain Iowa soils

Abstract

<p>The physical and chemical properties and bacteriological characteristics of a number of soils collected from various parts of Iowa were studied in an effort to determine what the possibilities were of distinguishing soil types in the laboratory. (1) No striking differences were observed in the physical and chemical properties which could be attributed to particular soil types. (2) Characteristic SiO2Al2O 3+Fe2O3 ratios were observed for each soil, but this property would not be considered sufficient to differentiate soil types. (3) Water extracts from soils did not show definite characteristics on which to base soil type separations, neither did the chemical analyses correlate with all of the chemical analyses of the soils. (4) Various ratios of water to soil yielded different amounts of soluble salts. However, not in all cases did the higher dilutions of water to soil yield the most soluble salts. (5) Studies on the base exchange complex of each soil indicated differences but what significance could be attached to some of the slight differences observed is a question. (6) The exchange complex of the Webster silty clay loam was distinctly more reactive than that of the other soils. (7) The bacteriological studies indicate that the soil colloids may have an important function in the life and growth of both the aerobic and anaerobic organisms found in soils.</p>