PHYSICAL-PROPERTIES OF SELECTED SOILS BY EROSION CLASS

The effects of soil erosion on soil fertility and yield have been docu mented with data as early as the 1900s, but there is limited literatur e relating soil erosion and soil physical properties. A regional resea rch project (NC-174) was established in 1984 to elucidate the effects of erosion on soil productivity, with respect to changes in soil physi cal properties, and to determine the potential for using computer mode ls to simulate this effect. Data are presented from 15 soils (sites) l ocated in eight states in the North Central United States. Based on th e thickness of topsoil, two to three levels of prior erosion were iden tified at-each location. Soil samples were collected and analyzed for bulk density, water retention, particle size analysis, and hydraulic c onductivity at saturation. Rooting depth for each soil was also determ ined from field observations. Soil erasion primarily affected the phys ical properties of the Ap horizon. Clay content of the Ap horizon incr eased with increasing erosion. In most cases, bulk density increased s lightly and hydraulic conductivity of saturated sail decreased. Change s in water content at given tensions were mixed with increases in some cases and decreases in others with erosion.