To assess the erosion resistance of soils beneath Robinia pseudoacacia (Robinia), soil anti-scouribility (AS) and its relevant structural properties in an age sequence of 4-, 11-, 24-, 37-, and 43-year-old Robinia, lands and one adjacent cropland (CK) were studied through a simulated flow scouring experiment on a hilly Loess Plateau. Soils from the six-stage Robinia planting were hypothesized to differ in their resistance to scouring, and these differences are believed to be related to differences in their soil physical properties. The results showed that:
1) Robinia planting significantly reduced sediment compared with CK. Changes in the sediment over scouring time were best described by a negatively exponential function.
2) Compared with CK, the average soil bulk density beneath Robinia significantly decreased by 14.5% in the surface (0-20 cm) soil layer and non-significantly by 5.7 and 3.3% in the middle (20-40 cm) and lower (40-60 cm) soil layers, respectively. Soil aggregate content and shear strength increased while soil disintegration rate decreased significantly in the three soil layers with Robinia stages. Mean 6.8, 1.6, and 0.2 times were increased in soil AS.
3) Linear regression equations between soil AS and the soil structural properties were well fitted in the surface and middle soil layers. Soil aggregate content and root biomass were the key factors, which contributed 71.0 and 90.8% to the reinforcement of soil AS beneath Robinia in the hilly Loess Plateau.