Discussion on vegetation reconstruction method of exposed rock slope in karst mountainous area

Mining activities and slope cutting and road building lead to the destruction of landform landscape, the destruction of soil vegetation resources, the exposure of slope bedrock, and serious soil and water loss. According to the failure type of rock slope, it can be divided into step slope, gentle slope ≤25° and high steep slope ＞25°. On the step slope, 30-60 cm slurry retaining wall is built on the edge of the step, and 30-60 cm soil is covered. Vines are planted on the edge and inside of the step, and shrubs are planted on the platform. Gentle slope ≤25° soil retaining measures are laid according to the slope ratio and similar triangle principle. The foundation is excavated during the masonry process of retaining sill to ensure that the foundation is stable and firm. The soil is separated and covered, and the native plants are planted for vegetation remodeling. High steep slope ＞25° drilling to plant shrubs and vines, and at the same time, set a breathable water guide hole（material exchange channel） at the lower end of the drilling hole. The breathable water guide hole can not only drain the excess water inside the hole out of the hole, prevent the rot and necrosis of vegetation roots due to long-term immersion of hypoxia, but also transport oxygen for vegetation roots, promote the absorption of nutrients in the roots, and improve soil porosity. It plays the role of conserving water. The above three methods of vegetation reconstruction of rock slope have the advantages of simple process, convenient construction, less project investment and long maintenance time. It can be widely applied in Wuling Mountain Area in northern Guizhou and even karst area in southwest China.