Assessment of the soil loss-prone zones using the USLE model in northeastern Iran

Abstract

This research attempted to evaluate the soil loss-prone zones and affecting key factors in a suburb agricultural area in the western Mashhad city, northeastern Iran, using the universal soil loss equation model. All erosion factors and components were produced in GIS grid-based modeling. Therefore, the required data, such as topography, climate, and soil characteristics, were collected from global databases. The estimated annual soil loss values were classified into five classes from slight soil losses (0–3 t ha−1 year−1) at the plain lowland in the northern region to severe soil losses (25–55 t ha−1 year−1) at the hillsides and terraces in the middle part of the study area. The results revealed that about 9.36% of the study area (6743 km2) is under critical erosion-prone zones of high and severe soil losses (over 15 t ha−1 year−1). Ultimately, the relationships between soil loss-prone zones and soil taxonomy order/sub-orders were investigated to prevalence the results in the other alike geo-climatic status. Correlation analysis conveniently confirmed a very strong, significant, and direct relationship (R equal to 0.997) between high/severe soil losses and xerolls in the study area at the 95% confidence level. In the study area, the most soil loss and sedimentation were predicted for xerolls soil sub-order (mollisols) with 5.5 t ha−1 year−1 and 14.69 million t year−1 (over 60% of total sedimentations).