Abstract:  With the intensification of global climate change and human disturbances, riverine ecosystems are increasingly threatened by severe slope-erosion processes. This study evaluates Magnolia multiflora and Cynodon dactylon as slope-protection species by examining their root-system development, tensile properties, and reinforcement effects on soil shear strength across distinct growth stages. The influence of rainfall on slope runoff velocity and sediment yield under each vegetation type is further assessed. Results demonstrate that the interwoven distribution of roots within clay soils markedly enhances soil shear strength, primarily through increased cohesion, with M. multiflora exhibiting a stronger strengthening effect than C. dactylon. Vegetated slopes covered by M. multiflora and C. dactylon reduce runoff velocity by 35.38%~45.53% and 45.11%~52.55%, respectively. Correspondingly, sediment yield decreases by 59.2%~94.33% under M. multiflora and 45.88%~86.82% under C. dactylon. While C. dactylon provides superior sediment-reduction performance, M. multiflora contributes more substantially to improving soil shear resistance. Both species exhibit strong potential for slope stabilization and erosion mitigation, indicating that vegetation selection in engineering applications should be guided by local climatic and hydrological conditions.

Key words: Slope Erosion, Slope Protection Plants, Shear Strength, Sediment Production Rate