Temperature sensitivity (Q10) of soil organic carbon (SOC) decomposition is an important index to estimate the dynamics of soil C budget. However, the spatial variation of Q10 and its influencing factors remain largely uncertain. In this study, we reviewed the effects of climate environment, spatial geographic pattern, soil physicochemical property, vegetation type, microbial community composition and function, and global climate change on Q10 to summarize the general rule of each factor influencing Q10 and compare the relative contribution of each factor to Q10 in different ecosystems. The results showed that Q10 decreases with the increases of temperature and precipitation, but increases with the rise of latitude and altitude. The Q10 value is higher in grassland than that in forest, and also in coniferous forest and deciduous forest than that in evergreen broad-leaved forest. Carbon quality is negatively correlated with Q10, but the C quality hypothesis is not always valid with exogenous substrate input. For example, the increment of substrate availability may significantly increase Q10 in low-quality soils. Q10 decreases with the enhanced proportion of r-strategy microorganisms (Proteobacteria and Ascomycetes), but increases with the enhanced proportion of K-strategy microorganisms (Acidobacteria and Basidiomycetes). Q10 increases with elevated CO2 concentration, but declines with atmospheric nitrogen deposition. In natural ecosystems, Q10 is mainly regulated by temperature and C quality. Temperature is the main factor regulating Q10 in the topsoil while C quality is the main factor in deep soil. Our review provided a theoretical support to improve the coupled climate-C cycle model and achieved the C neutral strategy under global warming.
土壤有机碳(SOC)分解的温度敏感性(Q10)是估算土壤碳收支动态的重要指标,但其空间变异特征及影响因素仍有较大的不确定性。本研究主要从气候环境、空间地理格局、土壤理化性质、植被类型、微生物群落组成及功能、全球气候变化等方面对Q10的影响进行综述,总结各因子对Q10影响的一般规律,比较其在不同生态系统中的相对贡献。Q10随温度和降水的增加而减少,随纬度和海拔的升高而增加。草原SOC分解的Q10高于森林,针叶林和落叶林SOC分解的Q10高于常绿阔叶林。土壤碳(C)质量与Q10呈反比,但在有外源底物输入时,C质量假说并不总是有效,在低质量土壤中提高底物可利用性可显著提高Q10。Q10随土壤中r策略型微生物(变形菌门、子囊菌门)比例的增加而降低,随K策略型微生物(酸杆菌门、担子菌门)比例的增加而增加。大气CO2浓度升高增加了Q10,而大气氮沉降降低了Q10。在自然生态系统中,浅层土壤的Q10主要受温度调控,深层土壤的Q10主要受C质量调控。在全球变暖背景下,本研究可为完善气候-C循环耦合模型、实现“碳中和”战略提供理论支撑。.
Keywords: C quality; ecological factor; microorganism; organic carbon decomposition; temperature sensitivity.