Relation between Soil Properties and the Erodibility of Masa Soils (Granitic Soils)

Abstract

Erosion experiments were carried out under laboratory conditions to determine the index of erodibility of Masa soils. Fifteen soil samples were collected in Kyushu. They had a low clay and silt content but a high sand content. Simple regression analysis was used to relate the amount of soil loss to the physical and chemical properties, including mechanical composition, clay ratio, aggregate stability, dispersion ratio, and pH. Among these parameters, only the mechanical composition gave a correlation significant at 1%. The content of 2–20 μm particles showed the highest and positive correlation coefficient (r=0.884**) with the amount of soil loss, followed by the content of 2–53 μm (r=0.867**) and <53 μm (r=0.857**) particles, while the content of 200–2,000 μm particles showed a negative correlation (r=−0.818* *). The content of 2–20, 2–53, or <53 μm particles was proposed as an index of erodibility of Masa soils. Preferential erosion of silt-size particles is most probable.