Determining C- and P-factors of RUSLE for different land uses and management practices across agro-ecologies: case studies from the Upper Blue Nile basin, Ethiopia
Birhanu Kebede, Atsushi Tsunekawa, Nigussie Haregeweyn, Enyew Adgo, Kindiye Ebabu, Derege Tsegaye Meshesha, Mitsuru Tsubo, Tsugiyuki Masunaga, Ayele Almaw Fenta
Abstract
Cover and management (C) and support practice (P) are the most dynamic factors of the Revised Universal Soil Loss Equation- a widely used model to estimate mean annual soil loss. The aim of this study was, therefore, to determine C- and P-factors for four land management practices and three land use types in three agro-ecologies: Guder (highland), Aba Gerima (midland), and Dibatie (lowland) through selecting a rainfall erosivity (R)-factor model. We collected two seasons’ daily soil loss data from 42 runoff plots. Compared to the control, the P-factor in cropland ranged from 0.15 to 0.53 for soil bund, 0.18 to 0.5 for fanya juu, and 0.06 to 0.44 for soil bund with grass; and in non-cropland plots from 0.03 to 0.42 for trench with exclosure. The C-factor ranged from 0.004 for teff to 0.64 for chili pepper in crop land; and from 0.001 in degraded bushland to 0.49 in grassland for non-cropland. Overall, the average P-values decreased in the order midland > highland > lowland for cropland plots and highland > lowland > midland for non-cropland plots. Accurate determination of C- and P- factor values for the local conditions helps greatly improve soil loss prediction in this basin and other similar regions.