Mitigating Splash Erosion with Applying Bacillus subtilis Natto

Abstract

Soil erosion from upland fields affects not only soil productivity but also water environment. From the viewpoints of soil and water conservation, many strategies for mitigation of soil erosion were discussed. Especially, conservation strategy for mitigating splash erosion which is the first process of soil erosion should be considered. Moreover, biological crust mixing with microorganisms has been focused as one of the treatments for splash erosion. Therefore, two objectives were determined in this study. The first is to evaluate the effect of Bacillus subtilis Natto adding on mitigating splash erosion, and the second is to investigate the kinetic energy of raindrop to break the binding force of soil particles with hyphae of Bacillus subtilis Natto. Raindrop experiment was carried out with stainless cans and Mariotte bottle of splash erosion apparatus. Stainless cans were filled with soil, and then Bacillus subtilis Natto was applied. In addition, raindrop energy was changed through controlling the height of Mariotte bottle. Based on the experimental results, there was a tendency that soil loss from the cans applied Bacillus subtilis Natto was significantly lower than controlled cans. In addition, it was observed that Bacillus subtilis Natto mitigated splash erosion until kinetic energy of raindrop at 4.86×10^-5 J/drop. Therefore, it was concluded that Bacillus subtilis Natto is applicable for mitigation of splash erosion.