中文摘要：

利用LI-8100土壤呼吸自动观测系统于2013年5月和8月分别观测了北长山岛森林土壤碳通量以及土壤温度和湿度，并分析了土壤碳通量变化特征及其影响机制。结果表明：北长山岛森林土壤碳通量的昼夜变化均表现为单峰曲线，最高值出现的时刻大约在14：30，最低值出现的时刻大约在06：00。土壤碳通量日均值介于1．835-14．475μmol／（m2·s）。5月份刺槐林、黑松林和8月份刺槐林、黑松林的土壤碳通量与10cm深度处土壤温度都存在显著的指数型关系（P〈0．05），其温度敏感系数Q10依次为1．448，1．301，3．254和3．445；与0～10cm土壤湿度依次呈指数型、一元二次方程型、线性型关系。多元回归分析表明：北长山岛林地0～10cm处的土壤温度和湿度均为土壤碳通量的重要调控因子，且其协同作用能解释土壤碳通量73．1％-91．5％的变化情况。

英文摘要：

By employing the LI-8100 CO2 flux automatic monitoring system （LI-COR Inc. , Lincoln, NE, USA）, this paper measured the diurnal changes of the soil carbon flux in the artificial plantations on the Beichangshan Island of Shandong Province. The diurnal changes of soil carbon flux and its environmental factors such as temperature and wa- ter were analyzed. The results indicated that soil carbon flux appeared single diurnal pattern, with the peaks presented at about 14：30 and the lowest presented at about 06： 00. The diurnal average of soil carbon flux ranged from 1. 835 μmol/（ m2 · s） to 14. 475 μmol/（ m2· s）. Significant relationships were found between soil respiration rate and soil temperature （ 10 cm） ,which could be best described by exponential equations （ R2 = 0. 492 - 0.702, P 〈 0.05 ）. The Qm value was based on the exponential correlations, which represented the sensitivity of soil respiration to tempera- ture. Its values of Robinia pseudoacacia in May,Pinus thunbergii in May,Robinia pseudoacacia in Aug,Pinus thunber-gii in Aug were 1. 448,1. 301,3. 254,3. 445, respectively. There were exponential correlations （ R2 = 0. 689, P 〈 0. 05 ）, quadratic correlations （ R2 = 0. 819, P 〈 0.05 ） and linear correlations （ RE = 0. 363 - 0. 601, P 〈 0.05 ） be- tween respiration rate and soil moisture （0 ～10 em）. Owing to the soil moisture condition, the soil moisture in May had more influence on soil carbon flux than that in August. On the whole, the important regulative factors to soil carbon flux were soil temperature （10 cm）and soil moisture （0 ～10 cm） ,and its combined effect could account for more than 73.1% of the soil carbon flux changes on the Beichangshan Island（R2 =0.73 -0.91 ,P 〈0.05 ）.