You Ye-Ming, Wang Juan, Sun Xiao-Lu, Tang Zuo-Xin, Zhou Zhi-Yong, Sun Osbert Jianxin
College of Forest Science, Beijing Forestry University, Beijing 100083, China.
Institute of Forestry and Climate Change Research, Beijing Forestry University, Beijing 100083, China.
Sci Rep. 2016 Mar 1;6:22411. doi: 10.1038/srep22411.
Understanding the controls on soil carbon dynamics is crucial for modeling responses of ecosystem carbon balance to global change, yet few studies provide explicit knowledge on the direct and indirect effects of forest stands on soil carbon via microbial processes. We investigated tree species, soil, and site factors in relation to soil carbon density and mineralization in a temperate forest of central China. We found that soil microbial biomass and community structure, extracellular enzyme activities, and most of the site factors studied varied significantly across contrasting forest types, and that the associations between activities of soil extracellular enzymes and microbial community structure appeared to be weak and inconsistent across forest types, implicating complex mechanisms in the microbial regulation of soil carbon metabolism in relation to tree species. Overall, variations in soil carbon density and mineralization are predominantly accounted for by shared effects of tree species, soil, microclimate, and microbial traits rather than the individual effects of the four categories of factors. Our findings point to differential controls on soil carbon density and mineralization among contrasting forest types and highlight the challenge to incorporate microbial processes for constraining soil carbon dynamics in global carbon cycle models.
了解土壤碳动态的控制因素对于模拟生态系统碳平衡对全球变化的响应至关重要，然而很少有研究能明确揭示林分通过微生物过程对土壤碳的直接和间接影响。我们在中国中部的一个温带森林中，研究了与土壤碳密度和矿化作用相关的树种、土壤和立地因素。我们发现，土壤微生物生物量和群落结构、胞外酶活性以及大多数所研究的立地因素在不同的森林类型间存在显著差异，并且土壤胞外酶活性与微生物群落结构之间的关联在不同森林类型中似乎微弱且不一致，这意味着在与树种相关的土壤碳代谢微生物调节中存在复杂机制。总体而言，土壤碳密度和矿化作用的变化主要是由树种、土壤、小气候和微生物特性的共同作用导致的，而非这四类因素的单独作用。我们的研究结果表明不同森林类型对土壤碳密度和矿化作用存在差异控制，并凸显了在全球碳循环模型中纳入微生物过程以限制土壤碳动态的挑战。
