中文摘要：

亚热带杉木（Cunninghamiala nceolata）和马尾松（Pinus massoniana）在我国森林资源中占有十分重要的地位，研究它们的土壤与表层凋落物的呼吸有助于了解它们的碳源汇时空分布格局及碳循环过程的关键驱动因子。采用Li-Cor 6400-09连接到Li-6400便携式CO2／H2O分析系统测定湖南两种针叶林群落（2007年1月至12月）的土壤呼吸及其相关根生物量和土壤水热因子。研究结果表明：杉木和马尾松群落中土壤呼吸的季节变化显著，在季节动态上的趋势相似，都呈不规则曲线格局，全年土壤呼吸速率平均值分别为186．9mg CO2·m^-2·h^-1和242．4mg CO2·m^-2·h^-1。从1月开始，两种群落的土壤呼吸速率由最小值33．9mg CO2·m^-2·h^-1和38．6mg CO2·m^-2·h^-1。随着气温的升高而升高，杉木群落到7月底达到全年中最大值326.3mg CO2·m^-2·h^-1，而马尾松群落到8月中旬达到最大值467.3mg CO2·m^-2·h^-1，土壤呼吸的季节变化与土壤温度呈显著的指数相关，土壤温度可以分别解释土壤呼吸变化的91．7％和78．0％，和土壤含水量呈二次方程关系，土壤含水量可以解释土壤呼吸变化的5．4％和8．4％。由土壤呼吸与土壤温度拟合的指数方程计算9，0值，杉木和马尾松群落中全年土壤呼吸的90值分别为2．26和2．13，Q10值随着温度升高逐渐减小。两种群落土壤呼吸的差异主要受群落植被的根生物量、群落的凋落物量的影响。

英文摘要：

Aims Cunninghamia lanceolata and Pinus massoniana forest ecosystems in subtropical China are important in national carbon budgets because of their large area and amount of carbon storage. Soil respiration is the second largest flux in the global carbon cycle, but the effect of these forest ecosystems on soil respiration is inadequately understood. Our objectives were to compare soil respiration rate, soil temperature, soil moisture and Ql0 value of the two communities and to evaluate relationships between soil respiration rates and environment factors. Methods We examined seasonal variations of soil respiration using an infrared gas exchange analyzer （Li-Cor 6400-09） from January to December 2007 in Tianjiling National Forestry Park, Changsha. Soil temperature and moisture were measured at the same time at 5 cm depth. At the middle of January, April, July and October, we examined whole samples of root biomasses at 60 cm depth. We evaluated Q10 values of soil respiration and correlations between soil respiration and environment factors. Importantfindings The two communities had significantly different patterns in seasonal soil respiration processes. The two forests exhibited irregularly fluctuating curves during the study period with mean rates of soil respiration of 186.9 and 242.4 mg CO2·m^-2·h^-1 in C. lanceolata and P massoniana stands, respectively. Significant relationships were found between soil respiration rate and soil temperature in both communities and are best described by exponential equations. However, no significant relationships were found between soil respiration and soil moisture. Soil temperature and moisture could explain changes in soil respiration of 91.7% and 78.0% in the C. lanceolata community and 5.4% and 8.4%, in the P massoniana community. The relationship between soil respiration rate （y） and soil temperature （t） is described by the regression equation： y=34.09e^0.0815t （R^2=0.917, p〈0.001）, y=48.68e^0.0754t （R^2=0.780 3, p〈0.001）. R^2=0.917, p〈0.001.