戴云山土壤微生物碳利用效率的海拔变异规律及影响因素

Microbial carbon use efficiency (CUE) refers to the C transformation to microbial biomass from C uptake. Quantification of microbial CUE and its controlling factors can deepen our understanding of soil C cycle process and feedback to global change parameters. CUE, Cgrowth, Crespiration, qGrowth, qCO2 were measured by 18O-H2O-DNA labeling method at six elevational sites in the Daiyun Mountain, a subtropical montane forest, soil organic carbon, total nitrogen and phosphorus, microbial biomass carbon, nitrogen and phosphorus, stoichiometry imbalance of soil-microorganisms were measured to understand their controls on microbial CUE, microbial growth and respiration. We found: CUE varied from 0.1 to 0.4, and increased linearly with elevation; CUE was positively correlated with Cgrowth, Crespiration and qGrowth, but negatively correlated with qCO2, indicating that CUE increased with elevation by increasing microbial growth and inhibiting respiration; Stepwise regression analysis revealed that temperature was the first controlling factor for the elevation variation of microbial CUE in the subtropical forest ecosystem.