Abstract
The effects of physio-chemical properties and erosion control by applying organic matters for a Kunigami-maaji red soil in Okinawa, Japan was studied. The main findings of this study include: Kunigami-maaji soil sampled in Nago city is basically composed of four non-active clay mineralshalloysite, geothite, mica-likely mineral, and quartz. The non-activity characteristic of these clay minerals affects the soil structure and thus increases the erodibility of Kunigami-maaji soil. The organic matters such as charcoal, organic fertilizer and chip improved soil physical and chemical properties by raising the porosity. Artificial rainfall experiments showed charcoal treatment had the best effect in erosion control, followed by organic fertilizer and chip treatments. By applying 10% charcoal to soil, erosion was reduced by 70% compared with non-treated soil. The effectiveness of erosion control by applying organic matters was further assessed by non-dimensional tractive force and non-dimensional soil loss amounts calculated by using kinematic wave model.
