Jie Wang

and 6 more

Soil erosion-induced solute loss contributes to non-point source pollution (NPS). The extent and depth of soil solute involvement in runoff exchange processes are determined by soil disturbed depth ( Ds), encompassing runoff depth ( Dr), and effective mixing depth ( De). This study aimed to investigate the impacts of Ds on soil erosion and solute loss. The varying Dr (0.04 ~ 0.59 cm) and De (0.08 ~ 10.35 cm) were generated through rainfall (60, 90, and 120 mm h −1) and overland flow (0, 1, and 2 L min −1). Dr and De were quantified by the KMnO 4 and Br tracing methods, respectively. Additionally, runoff coefficient ( Rc), sediment concentration ( Cs), sediment yield rate ( Sy), Br concentration in runoff ( CBr), Dr, and De were determined at 2 or 3-minute intervals. Significant differences were observed in runoff initiation time ( Tr) (15 ~ 187 s), Rc (0.49 ~ 0.99), Sy (4.04 ~ 242.89 g m 2 min -1), Cs (2.88 ~ 48.66 g L -1), and CBr (0.70 ~15 601.26 mg L -1) across different Ds (F>3, P<0.01). A power function relationship was observed between Tr, Rc, and Ds ( R2adj> 0.89). Sy, Cs, and CBr demonstrated increasing trends with rising Ds, though the magnitude of these increases varied across different Ds ( R2adj> 0.55). Furthermore, a notable linear correlation was identified between cumulative runoff generation, sediment yield, Br loss, and mean Dr, De ( R2adj> 0.75). Collectively, Ds accounted for 64.9% and 46.2% of the variation in soil erosion and Br loss, respectively. These results would facilitate an improvement of NPS models.