Relation between Soil Properties and Erodibility of Red-Yellow (Ultisols) B Soils

Erosion experiments were carried out under laboratory conditions to determine the index of erodibility of Red-Yellow (Ultisols) B soils. Twenty-two soil samples were collected in Kyushu. A simple regression analysis was used to relate the amount of soil loss to the soil properties, including mechanical composition, clay ratio, aggregate stability, dispersion ratio, erosion ratio, air-dry ratio, and pH. Among these parameters, the aggregate stability (>53 μm) showed the highest and negative correlation coefficient (r= −0.836**) with the amount of soil loss, followed by the dispersion ratio (r=0.730**) and erosion ratio (r=0.746**). The aggregate stability was proposed as an index of erodibility of Red-Yellow B soils. When the samples were divided into Red soils and Yellow soils, the Red soils showed a lower erodibility than the Yellow soils did. This phenomenon may be ascribed to the higher aggregate-stability of the Red soils.