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 useful in developing effective soil conservation techniques in farms. The size-distribution and mechanical stability of soil may influence the size-distribution of sediment due to erosion. In this study, erosion and sediment characteristics were measured in simulated rainfall experiments for three forest soils of contrasting physical properties. Four erosion treatments combined varying slope and kinetic energy of rainfall to provide three effective levels of energy from rain and runoff. A comparison of soil loss and size-distribution (quantified as Mean Weight Diameter, MWD) of the uneroded soils with size-distribution of sediment indicated soil loss to be greatest and sediment finest for the soil which was most susceptible to wetting. In contrast, soil loss was low and sediment was coarse for the strongly aggregated soil. Indices of relative mechanical stability have been developed which will assist interpretation of sediment quality and erosion for a range of soils.