Chemical, Mineralogical, and Physical Property Differences Between Moderately and Severely Eroded Illinois Soils

Abstract

AbstractThe effects of degree of erosion on the chemical, mineralogical, and physical properties of seven Illinois soils were evaluated. At each site, separate map units of moderately and severely eroded phases of a soil series were located in the same field. These paired erosion phases occurred as a consequence of slight differences in slope gradient, slope shape, or slope length within a landscape position. Soil descriptions were made from pits located within each eroded phase of all seven soil series. Soil samples were taken with depth to measure the chemical, mineralogical, and physical properties of each phase of all soil series. The magnitude and direction of change in these parameters varied with soil series. For most soils studied, degree of erosion significantly reduced the organic C, and water storage porosity values of the Ap horizons. Clay mineral type estimates of the Ap horizons of severely eroded soils changed measurably as a result of thinner topsoils permitting the tillage equipment to mix underlying Bt horizon materials higher in hydrous mica or smectite into the topsoil. With increased degree of erosion, pH, cation exchange capacity, K and base saturation value trends varied with soil series. Erosion of soils with root restricting layers, such as dense subsoils, resulted in these layers occurring closer to the surface and in lower profile water storage capacities. Most of the soil property differences between moderately and severely eroded phases of a soil series would reduce the ability of the soil to produce crops. Successful management techniques for the restoration of the productivity of eroded soils will need to modity the chemical, mineralogical, and physical properties of the severely eroded soils.