Abstract: Slope ecological restoration is an important component in the construction of power transmission projects. Traditional spray-sowing technology uses cement as binding materials, which results in a low germination rate of vegetative substrate, restricting the ecological restoration efficiency. Taking the high-steep slope of power transmission construction project in the red soil area as research object, this study used seaweed polysaccharide, which is a polymer chemical binder, to replace cement, with addition of ecological fertilizer and fiber. Indoor direct shear tests and pot experiments were carried out with bermudagrass as the plant species to analyze the mechanical and planting properties of the neotype spray-sowing substrate in red soil. Results showed that seaweed polysaccharide and fiber were the main factors affecting the cohesion of the neotype spray-sowing substrate. Bermudagrass germination rate was negatively correlated with seaweed polysaccharide content, while was significantly positively correlated with ecological fertilizer content, and exhibited no significant correlation with fiber content. The optimum content of seaweed polysaccharide to improve the substrate cohesion was 1%. The addition of fiber could also improve the cohesion, and the maximum cohesion was achieved when fiber content was 0.75%. When the content of seaweed polysaccharide was 1% and the content of ecological fertilizer was 5%, the bermudagrass germination reached 100%. The research results would provide new technical references for ecological restoration of high-steep slopes in red soil areas.

Key words: High steep red soil slopes, Spray-mixed vegetation substrate, Seaweed polyacrylamide, Mechanical properties, Vegetation performance