中文摘要：

为了探讨森林地表N2O通量特征,在湖南省大山冲森林公园选取4种典型的亚热带森林类型：杉木人工纯林（CL）、马尾松-石栎-南酸枣针阔混交林（PM）、南酸枣-豹皮樟-四川山矾-台湾冬青阔叶混交林（CA）、青冈-石栎-马尾松-南酸枣常绿阔叶林（CG）,采用静态暗箱-气相色谱法测定4种森林类型的地表N2O通量,研究亚热带地区典型森林类型土壤N2O通量在生长季的变化特征。结果表明：在生长季除南酸枣-石栎林表现为N2O的汇外[-27.21μg/（m^2·h）],其余3种林分地表通量均表现为N2O的源,平均通量按从大到小的顺序为：马尾松-石栎林[34.61μg/（m^2·h）]〉杉木纯林[30.48μg/（m^2·h）]〉青冈林-石栎[5.82μg/（m^2·h）];从整个生长季来看,不同坡位马尾松-石栎林、杉木纯林、青冈林-石栎和南酸枣-石栎地表N2O通量的变化不明显;相关性分析表明,不同林分之间的N2O通量与土壤湿度、温度等理化性质有密切关系,土壤水分是影响该地区森林地表N2O通量的主要因子,温度通过影响土壤水分间接影响土壤N2O的释放量。

英文摘要：

Forest ecosystems, being a possibility of an important source in emission of N2O, were rarely studied, especially in subtropical soil N2O emissions from a variety of forest types. This study site was located at Dashanchong Forest Park, being about 50 km away from Changsha City, Hunan Province and one of typical subtropical region of south China, which was the main distribution area of broad-leaved evergreen forests. Using the enclosed chamber technique, soil N2O emissions from a variety of forest types were measured once a month for a year. And environmental factors were also made simultaneous observations, including temperature and soil moisture. The samples were plotted at one kind of pure forest （CL） which species was Cunninghamia lanceolata and three types of mixed forest： PM （composed by Pinus massoniana mainly）, CA （composed by Choerospondias axillaria mainly）, and CG （composed by Cyclobalanopsis glauca mainly）, respectively. In general, it was the sink of N2O for the CA plot, and the source of N2O for the rest three kinds of forest types. Surface fluxes of N2O in the growing season was -27.21 μg/（m^2·h） for the CA plot, 34.61 μg/（m^2·h） for the PM plot, 30.48 μg/（m^2·h） for the CL plot, and 5.82 μg/（m^2·h） for the CG plot, respectively. In the growing season, soil N2O flux from PM, CL, CG and CA were not changed significantly with different slope positions. Soil N2O fluxes were closed correlation with soil properties varied with different forest types. And the statistic analysis also showed the soil moisture content was the major factor affecting soil N2O emissions in the study area, and temperature indirectly affected soil N2O emissions by influencing soil moisture content.