Effects of Vegetation Configuration on Soil Aggregate Stability of Restored Cut Slopes

Abstract

Soil aggregate stability is an important indicator for evaluating the ecological restoration of engineered cut slopes. This study descriptively compared the soil properties and aggregate stability among vegetation treatments in model cut slopes in Wuhan, Hubei Province, Central China. Four treatments were established, each represented by one model slope: bare-slope (BS), grass (GS), shrub (SS), and grass–shrub (GSS). Soils were sampled at 0–10 and 10–20 cm depths approximately two years after vegetation establishment. Soil physicochemical properties and the water-stable aggregate content (WSA), mean weight diameter (MWD), geometric mean diameter (GMD), percentage of aggregate destruction (PAD), and soil erodibility factor (K) were assessed. Vegetated treatments showed a lower bulk density and higher soil organic carbon (SOC) and soil organic matter (SOM) contents than BS. For the 0–20 cm layer, the mean MWD and GMD across the three vegetated treatments were 30.05% and 6.93% higher than those of BS, respectively, whereas the mean PAD and K were 36.31% and 5.90% lower. The GSS had the highest MWD and lowest PAD, whereas the GS had the highest GMD and lowest K. An exploratory Pearson correlation analysis (n = 4) described the associations of SOC and the 1–5 mm macroaggregate fractions with soil aggregate stability indicators; the interpretation was limited to descriptive associations. These findings provide descriptive evidence for evaluating vegetation treatments in cut-slope restoration and may inform the vegetation selection in Central China.