土壌改良剤混入による赤土系国頭まあじの侵食抑制効果

Kunigami maji soil is a red soil that distributes in the central north of the main island of Okinawa Prefecture, Since this soil is abundant in fine particles and poor in coagulation force, it is extremely vulnerable to water, causing severe soil runoff when it faces rainfall. The muddy water generated by soil runoff inflicts serious effects on downstream territories, farm fields, rivers and oceans. Muddy water is factor to pollute water environment and destroy ecosystem. This research used a soil conditioner to control soil loss, and examined its control effect. As the soil conditioner, E-soiru was used. In an experiment using artificial rainfall, the amount of dispersed soil occupied about 20-30% of the amount of eroded soil, showing that this factor cannot be neglected. By blending E-soiru, the amount of eroded soil decreased by 39-92% at an inclination of 1.7° and by 59-89% at an inclination of 8.0°. The result showed the significant effect of the addition of E-soiru on soil loss control. In particular, when the volume ratio of Kunigami maji soil and E-soiru was at 1:05, the mixture showed the maximum effect.