Effects of soil internal forces on splash detachment and transport of aggregate fragments in Mollisols of Northeast China

Soil internal forces can affect aggregate breakdown, and then impact splash detachment and transport of aggregate fragments. However, currently, the processes of soil splash detachment and transport under different soil internal forces are still not fully understood. Thus, to determine the effects of soil internal forces on the splash transport process, two soils (Binxian soil and Keshan soil) in the Mollisols (black soil) of Northeast China were selected to analyse the detachment and transport characteristics of aggregate fragments under different splash distances (0–10, 10–20, 20–30, 30–40 and 40–50 cm) through simulated rainfall experiments. Different concentrations of KCl electrolyte (from 1 to 10−5 mol L−1) were employed as rainfall materials to regulate soil internal forces. The results revealed that the net pressure of soil internal forces and splash amount presented the same trend with decreasing electrolyte concentration, that is, increased initially (from 1 to 10−2 mol L−1), followed by levelling off (from 10−2 to 10−5 mol L−1). The splash amount and net pressure had an exponential relationship (p