中文摘要：

利用静态暗箱／气相色谱法对三江平原小叶章（Calamagrostis angustifolia）草甸进行N2O排放通量的日变化观测实验。结果表明，小叶章草甸土壤一植物系统和土壤的N20通量均具有明显的日变化规律，小叶章草甸土壤-植物系统和土壤的N20通量最大值均出现在16：00，最小值均出现在6：00，其变化趋势与气温、地表温度和5、10、15、20cm地温均呈正相关关系。小叶章植株的存在，促进了土壤-植物系统N2O的排放，土壤-植物系统N2O日平均通量是土壤的1．61倍。小叶章草甸土壤-植物系统N2O通量日变化的变异系数大于土壤。

英文摘要：

Diurnal variation of nitrous oxide （N2O） emission fluxes from Calamagrostis angustifofia meadow in Sanjiang Plain were measured by closed opaque chamber and gas chromatography system. The results have shown that N2O emission fluxes from the meadow soil-plant system and soil both had obvious diurnal variation patterns with maximum at 4：00 pm and minimum at 6：00 am, and the variation of the fluxes assumed positive correlations with air temperature, ground temperatures at surface and 5, 10, 15, 20 cm deep beneath. The N2O emission from meadow soil-plant system could be enhanced by Calamagrostis angustifofia. Average N2O fluxes from soil-plant system were 1.81 times as high as that from soil. The coefficient of variance （CV） of N2O emission fluxes from Calamaqrostis an.qustifolia meadow soil-plant system was higher than that from soil.