Laboratory Insights Into the Correlation Between Sediment Yield, Soil Electrical Conductivity and pH in Surface and Piping Erosion

Soil erosion, driven by factors such as water, wind, tillage and so forth, has significant impacts on both humanity and the environment. Soil erosion, including surface and subsurface (piping) erosion, significantly affects the environment and infrastructure. This research examines the impact of soil properties, that is, electrical conductivity (EC) and pH, on sediment yield in both surface and piping erosion. Rigorous laboratory experiments were conducted on slopes of 5%, 10% and 15%, using a soil profile that consisted of a 5 cm water-restrictive layer of clay loam and a 15 cm topsoil layer of loam. Three experimental configurations were devised: exclusive pipe flow at 27 L h⁻¹ (M1), rainfall intensity at 30 mm h⁻¹ (M2), and a composite scenario integrating both rainfall and pipe flow (M3), with each configuration executed three times. The pipe flow was simulated using a plastic tube with a 1 cm diameter, placed on top of the water-restrictive layer, which helped create conditions for subsurface flow. Results showed that sediment yield predictions varied with slope. For surface erosion, the most favourable performance was observed at 5% slope with pipe flow (R² = 0.76, NSE = 0.76), while combined scenarios performed adequately (R² = 0.71). At 10% slope, performance was good (R² = 0.66, NSE = 0.65), and at 15%, results ranged from acceptable to very good. In piping erosion, the combined scenario consistently performed best (R² = 0.78–0.91, NSE = 0.67–0.82), particularly at 5% and 15% slopes. These findings offer valuable insights into erosion dynamics and can help improve soil management strategies.