Work

Soil erosion and nitrogen loss characteristics of gravel-containing sloping farmland in the three gorges reservoir area

Year: 2026

Type: article

Abstract: Study region Three Gorges Reservoir (TGR) area, China. Study focus Soil erosion and associated nitrogen loss from sloping farmland present a critical global environmental challenge. However, research on how hydrodynamic characteristics influence soil erosion and nitrogen loss in gravel-containing sloping farmland remains limited. To address this knowledge gap, we conducted simulated rainfall experiments on gravel-containing sloping farmlands to further clarify the regulatory roles and impact pathways of hydrodynamic parameters in processes. New hydrological insights Gravel content significantly reduced infiltration rate and increased runoff rate. Sediment yield peaked at 20 % gravel content. Nitrate nitrogen (NO 3 - ) loss in runoff consistently exceeded ammonium nitrogen (NH 4 + ) loss. Gravel notably increased Stream power ( ω ), and the enhanced runoff further intensified the disparity between NO 3 - and NH 4 + loss in runoff. Model fitting showed that gravel amplified the effects of rainfall intensity and slope gradient on soil erosion and nitrogen loss. Partial Least Squares Structural Equation Model (PLS-SEM) revealed that experimental variables influenced nitrogen loss both directly through hydrodynamic parameters (path coefficient = 0.346) and indirectly via erosion characteristics mediated by hydrodynamics (path coefficient = 0.389). These insights underscore that managing the hydrodynamic processes, for instance by increasing Darcy-Weisbach friction factor ( f ), is key to controlling soil erosion and nitrogen loss in gravel-containing sloping farmland.

Source: Journal of Hydrology Regional Studies

DOI: 10.1016/j.ejrh.2026.103165