Soil Erodibility Across Land Use and Slope Gradients in Tokat Province, Türkiye

Abstract

Background: Soil erosion is a major form of land degradation in Türkiye, where steep topography, intensive land use, and changing climatic conditions increase soil susceptibility to erosion. Understanding how land use and slope gradients influence soil erodibility is therefore essential for sustainable soil management and conservation planning. Aims: This study aimed to investigate the relationships between land-use patterns, slope gradients, and soil erodibility in Tokat Province, Türkiye. Study Design: The study was a comparative, field-based soil erosion assessment across different land-use and slope classes. Place and Duration of Study: The study was conducted in Tokat Province, Türkiye, and soil samples were collected and analyzed between April and October 2024. Methodology: A total of 108 soil samples were collected from 0–20 cm soil depth under 0–5%, 6–29%, and >30% slope classes. Aggregate stability (AS), structural stability (SS), dispersion ratio (DR), and erosion ratio (ER) were evaluated under different crop management systems. Statistical analyses were performed to determine the relationships among soil erodibility parameters and topographic conditions. Results: Cropland soils exhibited the highest dispersion ratio values (78.8 ± 2.1%), whereas forest soils showed lower dispersion ratio values (66.9 ± 2.4%) and greater structural stability. Similarly, erosion ratio values were highest in croplands (84.86 ± 0.82%) and lowest in forest lands (79.06 ± 4.38%). Forest ecosystems maintained higher and more stable aggregate stability values (57.47–60.21%) than cropland (45.83–57.98%) and pasturelands (47.31–57.39%). A significant inverse relationship was observed between dispersion ratio and structural stability, indicating that greater dispersion potential increased susceptibility to aggregate degradation. Regression analysis also demonstrated a strong negative relationship between structural stability and the erosion ratio, confirming that structural stability is an important indicator of soil resistance to erosion. Aggregate stability decreased with increasing slope gradient, particularly in anthropogenically disturbed lands, whereas forest cover effectively reduced the negative effects of topography on soil properties. Conclusion: The results demonstrated that land use, slope conditions, and soil properties significantly influence soil erodibility. Natural vegetation cover improved soil resistance through higher organic matter accumulation and root development. Structural stability was identified as one of the most important factors controlling soil erodibility in the study area.