Study On Change Of Plant Community And Soil Property In Ecological Restiration Periods Of Copper Mine Tailings

With the artificial recovery slopes of Yangshanchong (YSC) and Shuimuchong (SMC) copper mine tailings as test objects, this paper studied the soil physicochemical properties, soil microbial biomass, soil respiration, soil enzyme activities and the contents of nutrient and metal elements inside plant, using methods of physicochemical analysis. The main objective of this paper was to explore the effect of structure and composition of different vegetation communities on heavy metal migration, microbial biomass C and N, and soil enzyme activities. The results indicated that:(1) The content of soil nutrient in the substrates (layers A and B) under covering Imperata cylindrica community was highest at YSC. The soil nutrient in the substrates (layers A and B) under early vetiver grass communities was comparatively well at SMC. The contents of available heavy metals (Cu. Zn) and total heavy metals (Al, Ca and Fe) were highest, and the change of available heavy metals and total metals in vertical direction was more complicated at YSC and SMC. In addition, the correlation between physicochemical properties and available heavy metals and total metals at YSC is better than SMC.(2) The soil microbial biomass C and N were relatively high, and the soil respiration and metabolic quotient were lower in the substrates (layers A and B) under covering Imperata cylindrica community at YSC. The soil microbial biomass C and N were quite high in the substrates (layers A and B) under early vetiver grass communities, and soil respiration was strongest under Imperata cylindrica community at SMC. The soil microbial biomass C and N, and respiration presented as decreases gradually in the soil vertical (from up and down) at YSC and SMC. Compare with YSC, the correlation between four soil microbial indicator and physicochemical properties, available heavy metal and total metals is poor at SMC(3) The activities of dehydrogenase. catalase, alkaline phosphatase and urease was higher in the substrates (layers A and B) under covering Imperata cylindrica community at YSC and in the substrates (layers A and B) under early vetiver grass communities at SMC. The activities of four soil enzymes presented as decreases gradually in the soil vertical (from up and down) at YSC and SMC. Furthermore, the correlation between the activities of four soil enzymes and physicochemical properties, available heavy metal and total metals at YSC is much better than SMC.(4) The content of total nitrogen was biggest in Amorpha fruticos, and the content of total phosphorus was highest in Rhus chinensis. and a significant positive correlation was presented between total nitrogen and total phpsphorus at YSC. Meanwhile, the highest content of total nitrogen and total phosphorus was accumulated in middle vetiver grass communities, and these had no significant correlation between total nitrogen and total phpsphorus at SMC. The metal elements enrichment in herb was stronger than woody, and the contents of Al, Cu, Fe, As, Cd and Cr were highest in Arthraxon prionodes, and the link of those metal elements was more closely each other, but they had less effect to total nitrogen and total phosphorus at YSC. In additional, the accumulations of different heavy metal were bigger in Vetiveria zizanioiaes at SMC. Compare with YSC, the correlation of different metal elements was less at SMC, but they had larger effect to total nitrogen and total phosphorus.