中文摘要：

用LI-COR-6400-09测定并研究湖南长沙樟树人工林生长季节土壤呼吸速率的日变化及季节变化规律,分析土壤呼吸与土壤水热因子的关系。结果表明：樟树林生长季土壤呼吸速率日变化呈单峰曲线,与5cm深处土壤温度日变化相一致,2者呈显著指数相关,P=0.003;樟树林土壤呼吸速率季节变化显著,呈不规则曲线波动,平均呼吸速率为4.0μmolCO2.m^-2s^-1,与5cm深处土壤温度之间呈显著指数相关,拟合方程为y=0.3242e0.1064x,R^2=0.903,P=0.001,与5cm土壤湿度呈显著二次曲线相关,模拟方程为y=-0.0261w2＋1.869w-28.406,R^2=0.436,P=0.05,土壤温度和湿度可以分别解释土壤呼吸变化的90.3%和43.6%;由拟合的指数方程计算出樟树林生长季节的Q10值为2.9,4—6、7—8和9—10月Q10值分别为3.08,1.59和2.72,呈现Q10值随土壤温度升高而下降的趋势;土壤呼吸速率同时受土壤湿度的影响,当土壤湿度小于35.8%时,土壤呼吸与土壤湿度呈正相关,但当土壤含水量超过35.8%这个阈值,土壤湿度就成了土壤呼吸的抑制因子。

英文摘要：

The diurnal and seasonal dynamics of soil respiration in the Cinnamomum camphora forest ecosystem of a subtropical area were measured at Huitong ecological station for Chinese Fir plantations （Changsha station） in Hunan, China. CO2 effluxes rate was monitored using an infrared gas exchange analyzer （LI-COR-6400-09） from April to October 2006, and the controlling factors, such as soil temperature and moisture were also recorded in the C. camphora forest. The results showed that the diurnal fluctuation of soil respiration accorded with that of the soil temperature at 5 cm depth, appearing single peak. The soil respiration exhibited an irregular fluctuated curve during the expenmental period with a mean rate of 4.0μmol·m^- 2 s^- 1. A significant exponertial corelation was found between soil respiration rate and soil temperature at 5 cm depth. However, significant relationships were not found between the soil respiration and the soil moisture at 5 cm depth. Soil temperature and moisture were able to be used to explain changes in soil respiration by 90.3 % and 43.6% in the C. camphora forest. The relationship between soil respiration rate （y） and the variable of soil temperature （t） and soil moisture （w） at 5 cm soil depth could be described by the following exponential equation： y = 0. 324 2e^0.164x, R^2 = 0.903, P = 0.001, and by quadratic equation： y = - 0.026 1w^2 ＋ 1.869w - 28.406, R^2 = 0.436, P = 0.05, respectively. Q10 value of the soil respiration was 2.9 during the growing season of C. camphora. The Qlo values were 3.08, 1.59 and 2.72, respectively in April to June, July to August. and September to October. Qlo value descended with soil temperature raised. When soil humidity less than 35.8%, the soil respiration rate was positively correlated to soil humidity, however, the highest soil respiration rate was under the condition of soil humidity more than 35.8 %.