Soil moisture effect on the temperature dependence of ecosystem respiration in a subtropical Pinus plantation of southeastern China
Soil moisture effect on the temperature dependence of ecosystem respiration in a subtropical Pinus plantation of southeastern China
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DOI：
10.1016/j.agrformet.2006.02.005
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发表时间：
2006-04
影响因子：
6.2
通讯作者：
X. Wen;Guirui Yu;Xiaomin Sun;Qingkang Li;Yunfen Liu;Leiming Zhang;C. Ren;Yu-ling Fu;Zheng-Quan Li
中科院分区：
文献类型：
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作者：
X. Wen;Guirui Yu;Xiaomin Sun;Qingkang Li;Yunfen Liu;Leiming Zhang;C. Ren;Yu-ling Fu;Zheng-Quan Li
温度变化是陆地生态系统呼吸季节性波动的主要原因。然而，其他因素，如土壤湿度，也影响生态系统呼吸。利用涡度相关技术对中国东南部亚热带种植园CO2交换进行了连续观测。在2003年异常干旱的夏季，研究了土壤含水量对生态系统呼吸的影响及其对温度的敏感性（Q10）。结果表明，干旱胁迫下土壤含水量显著影响了土壤呼吸速率的动态及其与温度的关系。土壤含水量对生态系统呼吸Q10值的影响可用二次函数来描述，而不是常用的乘法模型。回归模型分析表明，生态系统呼吸对土壤含水量的敏感性高于乘法模型。在干燥土壤条件下，乘法模型导致高估了呼吸对变暖的响应。生态系统呼吸对温度的敏感性随气温和土壤含水量的变化而变化。这在很大程度上妨碍了对生态系统呼吸作用季节动态的准确估计。
Variation in temperature accounts for most of the seasonal fluctuation of terrestrial ecosystem respiration. However, other factors, such as soil moisture, also influence ecosystem respiration. In this study, continuous measurement of carbon dioxide exchange was made over a subtropical Pinus plantation of southeastern China using the eddy covariance (EC) technique. The effect of soil water content on ecosystem respiration and its sensitivity to temperature (Q10) were examined during the unusual dry summer of 2003. The results indicate that soil water content significantly affected the dynamics of respiration rate and its relationship with temperature in the drought-stressed ecosystem. The effect of soil water content on the Q10value of ecosystem respiration is described best by a quadratic function, instead of the commonly used multiplicative model. The regression model analysis revealed that ecosystem respiration was more sensitive to soil water content than is estimated by the multiplicative model. The multiplicative model led to an overestimation of response of the respiration to warming under the dry soil condition. Sensitivity of the ecosystem respiration to temperature was found to vary with air temperature and soil water content. This, to a considerable extent, precludes accurate estimates of the seasonal dynamics of ecosystem respiration.