科研之友
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摘要
Understanding the temperature sensitivity (Q(10)) of soil respiration (R-s) and corresponding controlling factors is crucial for estimating the feedback of soil carbon pool to future climatic changes. In this study, trenching method was used to separate R-H and R-A. Simultaneous measurements of soil respiration and soil microclimate were conducted within two temperate forests (a birch forest and a spruce fir forest). We aimed to analyze the seasonal variations of the Q(10) of R-s and its two components (heterotrophic [R-H] and autotrophic [R-A]) and to find relevant influencing factors. The Q(10) values ranged from 0.3 to 5.4, and exhibited strong seasonal variation. The regression analysis showed a negative relationship between Q(10) and soil temperature in the two forests. Additionally, the Q(10) values of R-H were also negatively correlated with soil microbial biomass carbon. Positive relationships were found between the temperature dependency of R-H and soil organic carbon and C:N only in birch forest, and the seasonal dynamics for Q(10) of R-A was more dependent on fine root biomass compared to soil temperature in this forest. Soil moisture had no effects on the seasonal changes of Q(10) due to its slight fluctuation throughout the growing season. The Q(10) value of long-term was a little higher compared to that of short-term. These results emphasize the importance of independently exploring the short-term Q(10) of R-H and R-A; and a single apparent Q(10) should be used with caution in estimating soil CO2 emission under global warming.
- 出版日期2018-2-12
- 单位东北林业大学
