Abstract: With three types of ecological slope protection projects of rock slope, soil slope and rock soil mixed slope (geotechnical slope) in Xishan mining area of Taiyuan as the object, CCA ranking was used to examine the relationship between environmental factors and species distribution of different types of slopes, and analyze the impacts of environmental factors such as soil and topography on plant diversity. The results showed that geotechnical slope was rich in vegetation composition (8 families, 17 genera, and 19 species), including Asteraceae, Gramineae, Fabaceae, Vitaceae, Lamiaceae, Simaroubaceae, etc. The species richness, Shannon index, Simpson index, and Pielou evenness index of the geotechnical slope were significantly higher than that of soil slope and rocky slope. The artificial soil nutrient contents of the three types of slopes were significantly higher than that of the control. The ave-rage contents of total nitrogen (1.24 g·kg^-1), organic matter (21.28 g·kg^-1), and available potassium (0.21 g·kg^-1) of geotechnical slope were higher than that of rocky slope (1.02, 15.56 and 0.14 g·kg^-1) and soil slope (0.80, 11.65 and 0.15 g·kg^-1), respectively. Vegetation diversity was significantly related to soil factors, with organic matter and soil water content as the main limiting factors. Soil factors had greater impacts on vegetation restoration than topographical factors. Results of structural equation modeling showed that topographical factors, such as slope gradient, indirectly affected vegetation restoration by affecting soil moisture and nutrients.

Key words: slope protection engineering, artificial soil, environmental factor