Effectiveness of typical plant communities in controlling runoff and soil erosion on steep gully slopes on the Loess Plateau of China

Vegetation restoration is widely recognized as the most effective measure in controlling runoff and soil erosion under different climatic zones and topographical conditions. Nevertheless, few studies have been performed to quantify its effectiveness in controlling runoff and soil erosion on steep gully slopes in arid and semi-arid regions. This study was conducted to quantify the effectiveness of vegetation restoration in controlling runoff and soil erosion and further identify its main factors influencing runoff and soil erosion under typical plant communities on steep gully slopes of the Loess Plateau, China. Runoff and erosion were analyzed on monthly scale from 14 micro-plots for three consecutive years (2018-2020). The results showed that vegetation restoration can effectively reduce runoff and erosion. Compare to bare land, runoff and erosion reduced by 37.5% to 93.0% and 83.9% to 99.6% under different plant communities. The mean percent runoff and soil erosion reduction and the ratio of percent runoff reduction to percent erosion reduction of shrub community were 1.34, 1.06, and 1.29 times those of grass community. The corresponding values of grass community with tap root systems were 0.60, 0.91, and 0.64 times that with fibrous mot systems. Shrub community was more effective than grass community in reducing erosion, whereas grass community (especially with tap root systems) was more effective in maintaining runoff. Although runoff and erosion varied greatly between different plant communities, their relationships could be well simulated by power functions. Variations in runoff were primarily affected by rainfall amount, the maximum 30-minute intensity, 60-minute rainfall kinetic energy, litter coverage, and biological crust coverage. Variations in erosion were dominantly influenced by runoff, the maximum 30-minute intensity, plant canopy coverage, and litter density. Overall, our study suggested that grass community (especially with tap root systems) is likely a more suitable and advisable choice for vegetation restoration on steep gully slope in arid and semiarid regions. The results of this study provide the scientific guide for policy-making of vegetation restoration on steep gully slopes in arid and semi-arid regions, i.e. the Loess Plateau.

Automated summary

Vegetation restoration is recognized as an effective measure in controlling runoff and soil erosion. This study quantified the effectiveness of vegetation restoration on steep gully slopes of the Loess Plateau, China, showing that shrub communities are better at reducing erosion, while grass communities (especially with tap root systems) are better at maintaining runoff. Relationships between runoff and erosion under different plant communities can be well simulated by power functions.