394-1 Microbial Biomass and Activities in Response to Nutrition and Toxicity Factors in Amended Base Metal Mine Tailings.
Resutls showed that microbial biomass is stimulated by sucrose organic C and mineral N addition, which is also constrained if N is limiting with C/N ratio larger than 32. Besides, it is found significantly stimulated microbial biomass, respiration, mineralization, urease activity, invertase activity and neutral phosphotase activity in sugarcane and acacia biomass amended tailings, which are positively related to labiel C and N pool. Meanwhile, no significant differene were observed in biochar amended one. However, microbial metabolic quotients in all amended tailings are much higher than that found in soil, which may result from tailings toxicity. From the aspect of toxicity, in mixture of tailings and soil, it is found substrate induced microbial biomass is decreased with higher percentage of tailings. In addition, when there are more than 25% of soil in the mixture, no significant differences of metabolic quotient were found in the tailings and soil mixture, indicating an improvement of metabolic efficience or shift of microbial community, which are in need of further investigation.