土壤温度和湿度对鲁东南杨树人工林土壤呼吸的协同影响

利用GXH．3051红外C02气体分析仪结合自制密闭箱对鲁东南中龄杨树人工林（MAP）和成熟杨树人工林（MP）土壤呼吸、自养呼吸和异氧呼吸进行了为期2a的定位研究，分析土壤温度和湿度与土壤呼吸的关系及动态变化，探讨土壤温度和湿度对土壤呼吸的协同影响。结果表明，（1）MAP和MP土壤呼吸具明显的季节特征，均呈单峰变化，7月达到高峰，分别为4．43和3．55μm01·m-2．s-1，1月处于低谷，分别为0．72和0．54tmaol·m-2．S-1。（2）土壤温度与土壤呼吸的关系可用指数模型R=ae加’进行拟合，土壤湿度与土壤呼吸的关系可用线性模型R=aW＋b进行拟合。（3）土壤温度和湿度与土壤呼吸的综合关系可用非线性模型R=aebrWc较好地拟合，共同解释了MAP和MP不同年份土壤呼吸、自养呼吸和异氧呼吸的83．3％－85．1％、71％－79．2％、58．6％－76．5％和82．4％－88．3％、68．9％－78．2％、50．2％－78．2％，双因素模型明显优于仅考虑土壤温度或土壤湿度的单因素模型，表明鲁东南杨树人工林土壤呼吸主要受土壤温度和土壤湿度的协同影响。

Synergistic effects of soil temperature and moisture on soil respiration in Populus tremula plantations in southeast Shandong province

Soil respiration, heterotrophic respiration and autotrophic respiration were investigated in middle-aged Populus tremula plantation （MAP） and mature Populus tremula plantation （MP） with portable infrared CO2 gas analyzer （GXH-3051） combined homemade closed chamber in Linyi, Shandong Province for two years to analyze the dynamics of soil respiration and its correlations to soil temperature and moisture, and finally to determine the synergistic effects of soil temperature and moisture on soil respiration. The results showed that： （1）The soil respiration in MAP and MP showed distinct seasonal dynamics with unimodal curve in the field. Soil respiration was highest in July （4.43 and 3.55 pxnol.m-2.s-1, respectively） and lowest in January （0.72 and 0.54μmol.m2.s-1, respectively）. （2）The correlations between soil temperature and soil respiration, autotrophic respiration, soil heterotrophic respiration were all exponential with R= aebr, and the correlations between soil moisture and soil respiration and its components were all linear with Y=kx＋e. However, the effect of single factor on soil respiration and its components was under 81%. （3）The synergistic correlations between soil temperature, soil moisture and soil respiration were fit by the model R=aebtWc（ R stands for soil CO2 effiux, T for soil temperature and W for soil water content at 0-10 cm soil depth, and a, b, c for the constants） . Soil temperature and moisture together could explain soil respiration, heterotrophic respiration and autotrophic respiration 83.3%-85.1%, 71%-79.2%, 58.6%-76.5% and 82.4%-88.3%, 68.9%-78.2%, 50.2%-78.2% of MAP and MP, respectively. The results showed that the double factor model was better than single factor model. Therefore, soil respiration was affected synthetically by soil temperature and moisture of MAP and MP in field.