The Reseach On The Adaptability Of Ryegrass To The Polluted Soil In Xiangxi Lead-zinc Mine Area

In recent years,heavy metal pollution of soils has become a widespread problem.An alternative and widely-used approach with great advantages over traditional methods is phytoremediation of soil heavy metals,which is cost-effective and ecologically friendly.In this study, under the physical and chemical properties and heavy metal analysis of the waste solid in Xiangxi Pb-Zn mining area and its11kinds of dominant plant, in order to make sure the dominant plant enrichment characteristics. Ryegrass with the best stabilizing potential of the heavy metal bioremediation was selected to do indoor potted experiment to determine its ability of heavy metal concentration, analyze its physiological and biochemical characteristics in different fertilization conditions. Based on its different reaction mechanism under heavy metal stress, it is determined the optimal growth conditions. This research result provides some theoretical and practical basis for ryegrass repair a large area of polluted soil in Xiangxi lead and zinc mine.The main results are as follows:1To find out the accumulator and tolerant plants is the premise of regetation reconstraction. The ability of plant species to accumulate heavy metals was investigated in Xiangxi Pb-Zn mining area. The concentration of Cd, Pb and Zn in roots and shoots of11dominant species and soil were analyzed. The result showed that the soil was serious lean and contaminated with a exremely high heavy metals concentration of Pb (2789mg.kg-1), Cd (159.83mg.kg-1) and Zn (2892mg.kg-1) respectively due to the Pb-Zn mining tailings. The dominant species were Gramineae and Compositae on the investigated field. The biomass of above-ground part and ability of heavy metals up to transport of Chrysanthemum indicum L.,Setaira viridis(L.)Beauv and Miscanthusf loridulus were higher than other plant species, and the contents of some heavy metals in stems and leaves of above-mentioned three species were higher than that in roots, which indicating that these species had certain potential ability to remediate contaminated soil. The Cd concentration in shoots of Ficus tikoua reached152mg.kg-1, and the transfer coefficient was1.03, which exceeded the threshold of Cd hyperaccumulator. 2In order to study on the adaptability of Ryegrass in Xiangxi Pb-Zn mining area, The results showed that:ryegrass grow well in tail slag with10%agricultural soil tailings, under3%pig excrement processing perennial ryegrass biomass was biggest, and the growth was best,, followed by the3%phosphate fertilizer. And in this concentration Pb, Zn and Cd on enrichment capability is the strongest, achieved Zn content1829mg/kg, Pb content690mg/kg, Cd content18.5mg/kg, for the comparison of115.1%,113.4%,118,6%, followed by5%pig excrement and5%phosphate fertilizer.3The study on the physiological and biochemical characteristics of ryegrass under heavy metal stress, the results showed that:Ryegrass chlorophyll content, MDA content were higher than other treatments in3%pig manure and3%phosphate treatment, Ryegrass protein metabolism capacity of the strongest in1%swine manure treatment. SOD, POD, the CAT activeness is higher than the pure agriculture basically with the underearth level, and ryegrass antioxidant content in3%pig manure and3%phosphate treatment is much higher than that of control. It is concluded that3%concentration in tail slag on Ryegrass is the optimum growth concentration.