Modeling the impacts of agroforestry systems on the spatial patterns of soil erosion risk in three catchments of Claveria, the Philippines

Agroforestry is one of the preferred land-use options for smallholder farms in tropical landscapes due to its ability to increase land productivity and protect soil from erosion. We investigated the impacts of agroforestry and traditional monocropping systems on the spatial patterns of soil erosion risk in three catchment areas of Claveria, the Philippines, using WaTEM/SEDEM, a spatially distributed soil erosion model. The model predicts soil loss in catchments based on the Revised Universal Soil Loss Equation (RUSLE) by taking into account the influences of rainfall, soil erodibility, vegetation cover and 2-dimensional variations in landscape structure. The predicted soil erosion rates were transformed into risk values in order to identify areas with higher risk for erosion. Model results indicate a large spatial variability in soil erosion risk patterns, with higher risks occurring on slopes greater than 8% on land under non-agroforestry use. The soil erosion risk maps were used to formulate site-specific agroforestry recommendations for future landscape amelioration plans.