Evaluating the erodibility of major soils of Aba Gerima and Guder watersheds using simulated rainfall, implication for modeling soil erosion

Soil erodibility (K) is the intrinsic resistance of a soil to erosion which is a key factor required in soil erosion modeling and other process based models across the world. Soil erosion is a major problem in Ethiopia and estimation using models can help decision makers for interventions. But our K factor determinations in models have limitations and yet rare study has been done to determine K on process based approach. Disturbed soil samples of the five major soil types of Upper Blue Nile Basin, Ethiopia (Guder and Aba Gerima watershed) were collected from the field. Runoff plots’ using simulated rainfall was used to determine K values of soil. Rainfall simulator was used to generate runoff and sediment concentration data from the soils in one- hour simulated rainfall events, and an optical disdrometer was used to characterize the erosivity of the events. The results indicated that the K values of major soil types of the study area ranged between 0.046 to 0.140 t ha hMJ −1 mm −1 ha −1 . The lower K values was obtained in both Chromic Vertisols and Lithic Leptosols and were significantly ( P