EROSION AND SEDIMENT CHARACTERISTICS OF CULTIVATED FOREST SOILS AS AFFECTED BY THE MECHANICAL STABILITY OF AGGREGATES

Information on erosion and size-distribution of soil and sediment is u seful in developing effective soil conservation techniques in farms. T he size-distribution and mechanical stability of soil may influence th e size-distribution of sediment due to erosion. In this study, erosion and sediment characteristics were measured in simulated rainfall expe riments for three forest soils of contrasting physical properties. Fou r erosion treatments combined varying slope and kinetic energy of rain fall to provide three effective levels of energy from rain and runoff. A comparison of soil loss and size-distribution (quantified as Mean W eight Diameter, MWD) of the uneroded soils with size-distribution of s ediment indicated soil loss to be greatest and sediment finest for the soil which was most susceptible to wetting. In contrast, soil loss wa s low and sediment was coarse for the strongly aggregated soil. Indice s of relative mechanical stability have been developed which will assi st interpretation of sediment quality and erosion for a range of soils . (C) 1997 Elsevier Science B.V.