Abstract
To qualitatively evaluate the reduction effect of a planning measure on red soil runoff, a scenario for reduction of red soil was examined based on the results of sequential hydrological observation and the application of spatially distributed sediment runoff model in the small agricultural catchment (0.28km2) mainly cultivating sugarcane.Reflecting the spatial distribution of sugarcane planting type with a model parameter (C factor) improved the modelʼs performance. This simulated that sugarcane fields in the first year of summer planting were the main source of red soil production in the catchment by leaving the soil surface without any covering from early spring after harvesting to planting period. A proposed scenario simulated the application of cover crop (C.juncea) to the first year summer planting fields prior to planting sugarcane was confirmed to be very effective at the reducing red soil runoff volume in the entire catchment. In addition, the estimated cost for cover crop application corresponding to about 13% of the cultivation income from sugarcane. This suggests that policies should be developed to provide incentives to encourage farmers to voluntarily cultivate a cover crop to sustainably work for the reduction of red soil runoff.
