Assessment For Original Plant Community Impacted By Freeway Construction

Construction of the expressway destructs seriously the ecological environment within proverty line. And the plants can mostly indicate the condition of the environment. Therefore, researching the relationship between plants and environment can discusses the adaptation of plants in different segions, which will support theoretically for the afforestation and ecological rebuilding of the expressway. Before researching the relationship, it is need to know how to investigate the state of the plant communities in the original ecological environment and the physical and chemical characteristics of the top soil which is indispensable to the plant, and then give the "original coordinate" of the plant communities when researching the expressway constructing impact on the original plant communities. The related studies were conducted from August, 2005 to April, 2006 to these problems and the main results were as follows:1. The parameters including original constitution of plant communities, domain plants, ages and heights of plants, density, biomass, coverage and species diversity of plant communities are mensurated in four sampling sites (three sampling sites are treating sites and one sampling site is checking site), which indicates the condition of the original plants communities.2. The main results are showed according to investigation for the physical and chemical characteristics of the top soil along the middle section of Suizhou-Yueyang expressway: In the forest ecological areas (K7+500～K47+000), the type of top soil mainly is yellow umber, and the texture is arenaceous. According to the tested pH values, the soil is acidic or little acidic. There are little organism and nitrogen contents in the soil, which is also badly lock of phosphor. Although there are sufficient kalium in soil, content of the available kalium is not enough to the growth of plants. In summary, the nutrient contents are deficiency and the soil in this area is inadequate to hold fertility. In the agricultural ecological areas (K0+000～K7+500 and K47+ 000～K152+877.6), the type of top soil mainly is paddy soil, and the texture are heavy loam and clay, which contain a little grits. According to the tested pH values, the soil is acidic or litmusless. There are high organism and nitrogen contents in the soil, which is also badly lock of phosphor. Although there are not enough kalium in soil, content of the available kalium is sufficient for the growth of plants. In summary, the soil in this area is rich in the nutrient and can be efficient to hold fertility. And then the thesis puts forwards some suggestions about the fertilizations, managements, improvements of soil according to the different edaphic physicochemical properties in the forested and agricultural ecotypic sections, so as to select plant to plant suitably.3. The linear equation of organism and nitrogen contents in the soil along the expressway is y=0.063x-0.0843(n=9), and the relativity coefficient is 0.9313, which illuminates that the organism content of the top soil is highly linearly relative to nitrogen content.4. Give a suggestion about scientifically selecting plants for afforestation according to the investigation to constitute of the original plant community and physical and chemical characteristics of the top soil along the expressway.