Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, China.
Institute of Ecology and Forest, Sichuan Agricultural University, Chengdu, China.
PLoS One. 2018 Sep 27;13(9):e0204341. doi: 10.1371/journal.pone.0204341. eCollection 2018.
Partitioning the components of soil respiration is crucial to understand and model carbon cycling in forest ecosystems. In this study, total soil respiration (RS), autotrophic respiration (RA), heterotrophic respiration (RH), litter respiration (RL), litterfall input and environmental factors were synchronously monitored for 2 years in a subtropical Michelia wilsonii forest of southwestern China. RH rates were often higher than RA rates during the two years except for the middle growing season (from July to September). The mean rate of Rs, RA, RH and RL was 1.94 μmol m-1 s-1, 0.85 μmol m-1 s-1, 1.09 μmol m-1 s-1 and 0.65 μmol m-1 s-1, respectively, during the 2-year experiment. Annual CO2 emission derived from RA, RH and RL was 3.26 Mg C ha-1 a-1, 4.67 Mg C ha-1 a-1 and 2.61 Mg C ha-1 a-1, respectively, which accounted for 41.4%, 58.6% and 32.9% of RS. Over the experimental period, the ratio of RA/RS increased with soil temperature but the opposite was true for RH/RS and RL/RS. The Q10 value was 2.01, 4.01, 1.34 and 1.30, respectively, for RS, RA, RH and RL. Path analysis indicated that environmental variables and litterfall production together explained 82.0%, 86.8%, 42.9% and 34.7% variations of monthly fluxes of RS, RA, RH and RL, respectively. Taken together, our results highlight the differential responses of the components of RS to environmental variables.
土壤呼吸的组成部分的划分对于理解和模拟森林生态系统的碳循环至关重要。本研究在中国西南地区的一个亚热带 Michelia wilsonii 森林中同步监测了 2 年的总土壤呼吸（RS）、自养呼吸（RA）、异养呼吸（RH）、凋落物呼吸（RL）、凋落物输入和环境因素。除了生长中期（7 月至 9 月）外，在这两年中，RH 速率通常高于 RA 速率。在 2 年的实验中，Rs、RA、RH 和 RL 的平均速率分别为 1.94 μmol m-1 s-1、0.85 μmol m-1 s-1、1.09 μmol m-1 s-1 和 0.65 μmol m-1 s-1。从 RA、RH 和 RL 得出的年度 CO2 排放量分别为 3.26 Mg C ha-1 a-1、4.67 Mg C ha-1 a-1 和 2.61 Mg C ha-1 a-1，分别占 RS 的 41.4%、58.6%和 32.9%。在实验期间，RA/RS 与土壤温度呈正相关，而 RH/RS 和 RL/RS 则相反。Q10 值分别为 2.01、4.01、1.34 和 1.30，对应于 RS、RA、RH 和 RL。路径分析表明，环境变量和凋落物产量共同解释了 RS、RA、RH 和 RL 月通量变化的 82.0%、86.8%、42.9%和 34.7%。总的来说，我们的结果强调了 RS 组成部分对环境变量的不同响应。
