The Studies On Vegetation And Soil At Early Vegetation Restoration Stage On Expressway Rock Slope

This paper which was based on the construction project of Beijing-chengde expressway associating the specific circumstances of this expressway project, researched on the vegetation and soil at early vegetation restoration stage. Through the investigation and analysis of community, the changeful regulation of community quantitative during early vegetation restoration was studied. Through the analysis of soil physical-chemical property, it is necessary to understand that the soil nutrient supply for the slope's plants. The main results are as follows:(1)With the passage of time, Coverage of initial planting of species changed. The maximum coverage reached 90﹪in the different plant arrangement models in different time .Based on the research of the plant growth , the change tendency of plant average height was slow growth- rapid growth-slow growth pattern in different plant arrangement models.(2) In the process of vegetation restoration on rock slopes,the number of species changes. The species has increased from the initial 3 families 6 species to the later 5 families 13 species and the species has experienced the enrichment. The percent of Legumina in the plant composition increased.(3)Based on the research of community diversity, the fluctuate trend of all species diversity index were similarly in community. The change of Simpson and pielou evenness index was more gently than Shannon-wiener diversity index and Margalef's richness index. The change of diversity index had no evident in different plant arrangement models.(4)In the process of vegetation restoration, vegetation and soil are two aspects that are interplaying and interacting each other. The physical characteristic of soil was ameliorated as vegetation growth. Soil water capacity, soil porosity, water infiltration rate increased along with vegetation restoration, while soil bulk density decreased along with vegetation restoration. Soil organic matter, total N,available P,available K had seasonal change, and the correlation analysis found that soli organic matter was correlated positive with soil total N.