Effects of soil surface electrochemical properties on soil detachment regulated by soil types and plants

Soil surface electrochemical properties play an important role in soil detachment. However, the effects of soil surface electrochemical properties on soil detachment have received little attention. This study selected three typical soil types (sandy loam, silt loam and silt clay loam) and two typical herbaceous plants (Stipa bungeana Trin. and Artemisia gmelinii Web. ex Stechm., with an abandoned cropland) to quantify the effects of varied soil surface electrochemical properties caused by soil types and plants on soil detachment on the Loess Plateau, China. A hydraulic flume test was conducted under five flow discharges (0.1, 0.2, 0.3, 0.4 and 0.6 L s^-1) on a 15° slope. The results showed that large differences in soil surface electrochemical properties occurred among different soil types and plant species. The exchangeable sodium percentage (ESP), cation exchange capacity (CEC), specific surface area (S), surface charge density (σ₀), surface potential (φ₀) and surface electric field strength (E₀) ranged from 1.02% to 2.26%, from 7.26 to 24.34 cmol_c kg^-1, from 8.32 to 147.38 m² g^-1, from 0.09 to 2.02C m^-2, from -81.33 to -149.92 mV and from 1.23 × 10⁸ to 28.46 × 10⁸ V m^-1, respectively. The soil detachment capacity (Dc) was significantly correlated with ESP (P < 0.01), E₀ (P < 0.01) and |φ₀| (the absolute value) (P < 0.05). Moreover, Dc exponentially increased with |φ₀| (R² = 0.99) and linearly increased with ESP (R² = 0.85) and E₀ (R² = 0.95). Therefore, soil surface electrochemical properties greatly varied with soil types and plants and had a significant effect on soil detachment.