Abstract: China’s diverse terrain and frequent extreme weather events have exacerbated rainfall-induced erosion on slopes. This study introduces an innovative approach by integrating vegetation with microbially induced calcium carbonate precipitation (MICP) technology to improve slope erosion resistance. Through pot experiments and large-scale slope model rainfall tests, complemented by scanning electron microscopy (SEM) and low-field nuclear magnetic resonance microscopic analyses, this study systematically examined the effects of MICP on runoff erosion in vegetation-protected slopes and investigated the erosion resistance mechanisms of MICP-vegetation cooperative protection systems. The results indicate that: (1) Compared with the untreated slope, MICP-vegetation synergistic protection slightly increased runoff but significantly reduced soil loss. The optimal erosion resistance was achieved with a cementation solution concentration of 0.15 mol/L, which reduced runoff and soil loss by 12.37% and 90.74%, respectively, and increased vegetation coverage by 2.13% compared with the bare slope. (2) Microscopic analysis revealed that MICP fills soil pores through calcium carbonate precipitation, with crystal density increasing proportionally to cementation solution concentration. This process enhances soil cohesion and shear strength, ultimately improving soil erosion resistance. (3) During the pre-seedling stage, slope protection primarily relies on MICP-induced chemical cementation, which quickly forms a calcium carbonate bonding layer on the soil surface to stabilize the slope. After vegetation matures, the combined protection mechanism of MICP and vegetation ensures slope stability and significantly mitigates soil and water loss. These findings advance the theoretical framework of MICP–vegetation synergistic slope protection technology and offer scientific guidance for soil and water conservation efforts.

Key words: microbially induced calcium carbonate precipitation (MICP), MICP-vegetation synergistic slope protection, vegetation slope protection, slope surface runoff, soil erosion