土壤养分及其化学计量特征对微生物碳利用效率的影响机制

Impacts of Soil Nutrients and Stoichiometry on Microbial Carbon Use Efficiency

土壤微生物碳利用效率(CUE)用以评估生态系统中微生物将有机碳转化为自身生物量的效率,其大小反映生态系统碳同化和固持的能力。本文以土壤养分及其化学计量比对微生物CUE的影响为主线,详细综述土壤有机质质量、养分可利用性、碳氮磷和胞外酶化学计量比以及由养分限制所引发的微生物群落结构改变和有机质激发效应等对CUE影响的机理,并讨论气候、生态系统类型和土地利用方式、土壤深度和理化性质等通过影响土壤养分状况而对微生物CUE产生的间接作用机制,在此基础上分析微生物CUE研究中研究方法和研究尺度上所面临的挑战,并展望未来关注的重点科学问题。

Soil microbial carbon use efficiency(CUE)is an index to evaluate the efficiency of microorganisms to incorporate organic carbon into microbial biomass in ecosystems.This index reflects ecosystems’ability for carbon assimilation and sequestration.This paper mainly reviewed the researches on the impacts of soil nutrients and stoichiometry on microbial CUE,and summarized the mechanisms of the effects on CUE from the angles of the quality of soil organic matter,nutrient availability,stoichiometry of carbon,nitrogen,phosphorus and extracellular enzyme activities,nutrient limitation induced change in microbial community structure and organic priming effect.Furthermore,the indirect influences of climate,ecosystem and land-use types,soil depth and physiochemical characteristics to microbial CUE via their impacts on soil nutrient status were discussed.On the basis of the above analysis,the challenges in research approaches of microbial CUE and scales,and the future research directions were discussed.