Lithology-mediated soil erodibility characteristics after vegetation
restoration in the karst region of southwest China
Abstract
Ecological restoration projects have significantly contributed to the
global increase in vegetation cover and the reduction of soil erosion.
However, the impact of lithology in the karst ecosystem on changes in
soil erosion characteristics during vegetation restoration remains
unclear. This study aims to investigate the soil erosion characteristics
of hillslopes under different vegetation restoration strategies in the
fragile karst areas composed of limestone and dolomite. The restoration
strategies mainly include arbor forest (AF), orchard (OC), and grassland
(GL), with cropland (CR) as the control. Soil physical-chemical
properties and soil erodibility factors (K EPIC, K
NOMO) were used to evaluate soil erosion
characteristics. The results showed that, in comparison to cropland,
both limestone and dolomite in restoration strategies exhibited lower
soil bulk density (BD) and soil erodibility K values, as well as higher
capillary porosity (CP) and soil water-stable aggregates (WSA). However,
the K value of limestone (17.9%) was significantly higher compared to
dolomite. Additionally, limestone exhibited significant changes (
p < 0.05) in soil properties, such as BD, organic
matter content (OMC), CP, and WSA. Conversely, dolomite did not show
significant changes in these soil properties. These findings indicate
that vegetation restoration was effective in improving soil structure
and erosion resistance, and dolomite exhibit higher stability compared
to limestone. Through redundancy analysis, it was observed that soil
texture, represented by silt content, was the primary parameter
indicating changes in soil erosion characteristics following vegetation
modification. The silt content explained 84.4% and 78.2% of the
variation in K values for limestone and dolomite, respectively.
Moreover, the changes in K values for dolomite were also controlled by
OMC, whereas limestone was solely controlled by soil texture. These
findings suggest that the interactions between soil properties
contribute to the improvement of stability in dolomite. Accordingly,
vegetation restoration enhances soil erosion resistance; however, the
effectiveness of restoration was controlled by the lithology in the
southwestern karst region.