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以重庆缙云山亚热带针阔混交林为研究区,研究了土壤呼吸及其Q10(温度敏感性系数,指温度增加10℃所造成的呼吸速率改变的商)的时间变异特征,并深入分析二者受土壤温度、湿度变化的影响.2011年4—12月采用LI-8100二氧化碳通量测量系统观测选取样地的R S(土壤呼吸速率)、土壤5 cm深处的T5(土壤温度)和W5(土壤湿度),分析R S与Q10的变化规律;同时利用单一和二元混合模型探讨T5和W5对R S、Q10的影响.结果表明:①在观测期内R S和T5月均值均呈单峰曲线变化;R S的变化范围在(1.38±0.15)～(3.94±0.21)μmol/(m2·s)之间,T5的变化范围在(9.28±0.65)～(22.99±1.14)℃之间;由于受到自然降水影响,W5的月际变化不规律.②Q10季节差异明显,最大值(3.31)出现在春季,观测期内的平均值为2.01.③R S与T5之间呈显著正相关(P<0.05),与W5的关系不明显(P>0.05);R S与T5、W5的关系模型拟合度分别为87%和26%;T5与W5的复合模型对R S的变化解释能力为89%,高于单一模型.④影响Q10的主要因素是T5,其次为W5.
Taking the subtropical mixed coniferous and broad-leaved forest in Jinyun Mountain of Chongqing as the study area, the temporal variation characteristics of soil respiration and its Q10 (temperature sensitivity coefficient, which refers to the change of respiratory rate caused by the temperature increase of 10 ℃) were studied. Soil Temperature and Humidity Changes The RS (soil respiration rate), T5 (soil temperature) at a depth of 5 cm and W5 (soil temperature) were measured using the LI-8100 carbon dioxide flux measurement system from April to December 2011 Humidity and moisture content, and analyzed the variation regularity of RS and Q10. At the same time, the effects of T5 and W5 on RS and Q10 were discussed by single and binary mixed models. The results showed: RS ranged from 1.38 ± 0.15 to 3.94 ± 0.21 μmol / m2 · s and T5 ranged from 9.28 ± 0.65 to 22.99 ± 1.14 ° C. As a result of natural precipitation (P <0.05) .Whereas, the monthly variation of W5 is irregular .②The seasonal variation of Q10 is obvious, the maximum (3.31) appears in spring, and the average value during the observation period is 2.01.③R S and T5 showed a significant positive correlation (P <0.05) W5 was not significant (P> 0.05). The relationship between RS and T5 and W5 was 87% and 26%, respectively. T5 and W5 Changes in the composite model of R S explanatory power of 89%, higher than the single model .④ the main factors affecting Q10 is T5, followed by W5.