Abstract: Through quantitatively adjust soil electric field, we investigated the effect of soil electric field on aggregate stability and soil erosion in black soil region of Northeast China with the experiments of wet sieving and rainfall simulation. Results showed that: 1) Soil surface potential absolute value and electric field strength increased with the decreases of electrolyte concentration in bulk solution. Soil electric field strength could reach to 10⁸ V·m^-1. 2) With the increase of soil electric field strength, the degree of fragmentation of soil aggregates increased and the mean weight diameter (MWD) decreased sharply first and then kept constant. 3) With decreasing electrolyte concentration and increasing surface potential, the amount of soil loss increased. As the electrolyte concentration was <0.01 mol·L^-1, the corresponding soil surface potential was > 210 and 209 mV for Bin-xian and Keshan, respectively, the cumulative amounts of soil loss with rainfall time almost overlapped, suggesting that the electrolyte concentration of 0.01 mol·L^-1 was the threshold for soil erosion. 4) There was a linear relationship between soil cumulative loss and MWD. Our results indicated that soil electric field strength increased as the rain enters into the soil, which could induce soil aggregate breakdown and release amounts of fine soil particles. Finally, soil erosion occurred under the driving of flowing water. Our results provided insights into the mechanism underlying soil erosion in the black soil region of Northeast China.

Key words: soil erosion, soil electric field, surface potential, aggregate stability