Soil Erosion: A Review of Models and Applications

Soil erosion is a global environmental problem influenced by both natural and human factors. Modeling provides a quantitative and consistent approach to estimate soil erosion and sediment yield under a wide range of conditions, and is needed to guide the comprehensive control of soil erosion. Over the years various soil erosion models have been developed. The application of these models is dependent on the soil type and climate of the given area because models differ in complexity and input requirements. This paper reviews various soil erosion models and their applications, focusing more on the most widely applied models which are: Universal Soil Loss Equation (USLE), Revised Universal Soil Loss Equation (RUSLE) and Water Erosion Prediction Project (WEPP). The method used for this research is a review of academic articles, bulletins, conference papers, textbooks, research reports and publicly available materials on soil erosion models and their applications. The results of this study revealed that most soil erosion models have been developed for the assessment of rill and interill erosion at plot or catchment scale on agricultural lands and watersheds in terms of estimating mostly soil loss, sediment yield, erodibility (K) values, rainfall factor (R) factors, runoff rates and forecasts of likely impacts. Again, the study indicated that most previous authors on soil erosion assessment used the empirical models due to their limited data and parameter inputs. Recommendations of this study include: (1) expansion of the USLE and RUSLE models for the simulation of gully erosion and sediment processes; (2) researchers should be encouraged through grants to develop empirical models (that make use of limited data) based on rainfall (R) factor and erodibility (K) factor that provide two opposing forces in soil erosion processes; and (3) management of soil erosion based on the indigenous knowledge of the affected people and land holders.