Wei Hui, Chen Xiaomei, Xiao Guoliang, Guenet Bertrand, Vicca Sara, Shen Weijun
Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
School of Geographical Sciences, Guangzhou University, Guangzhou 510006, China.
Sci Rep. 2015 Dec 16;5:18370. doi: 10.1038/srep18370.
Soil temperature and moisture are widely-recognized controlling factors on heterotrophic soil respiration (Rh), although they often explain only a portion of Rh variability. How other soil physicochemical and microbial properties may contribute to Rh variability has been less studied. We conducted field measurements on Rh half-monthly and associated soil properties monthly for two years in four subtropical forests of southern China to assess influences of carbon availability and microbial properties on Rh. Rh in coniferous forest was significantly lower than that in the other three broadleaf species-dominated forests and exhibited obvious seasonal variations in the four forests (P < 0.05). Temperature was the primary factor influencing the seasonal variability of Rh while moisture was not in these humid subtropical forests. The quantity and decomposability of dissolved organic carbon (DOC) were significantly important to Rh variations, but the effect of DOC content on Rh was confounded with temperature, as revealed by partial mantel test. Microbial biomass carbon (MBC) was significantly related to Rh variations across forests during the warm season (P = 0.043). Our results suggest that DOC and MBC may be important when predicting Rh under some conditions, and highlight the complexity by mutual effects of them with environmental factors on Rh variations.
土壤温度和湿度是公认的控制异养土壤呼吸（Rh）的因素，尽管它们通常只能解释Rh变异性的一部分。其他土壤物理化学和微生物特性如何影响Rh变异性的研究较少。我们在中国南方的四个亚热带森林中，对Rh进行了为期两年的半月一次的实地测量，并每月测量相关土壤特性，以评估碳有效性和微生物特性对Rh的影响。针叶林的Rh显著低于其他三种以阔叶树种为主的森林，并且在这四个森林中呈现出明显的季节变化（P < 0.05）。在这些湿润的亚热带森林中，温度是影响Rh季节变异性的主要因素，而湿度则不是。溶解有机碳（DOC）的数量和可分解性对Rh变化具有显著重要性，但通过偏mantel检验发现，DOC含量对Rh的影响与温度相互混淆。在温暖季节，微生物生物量碳（MBC）与不同森林中的Rh变化显著相关（P = 0.043）。我们的结果表明，在某些条件下预测Rh时，DOC和MBC可能很重要，并突出了它们与环境因素对Rh变化的相互作用所带来的复杂性。
