中文摘要：

为深入了解烟田生态系统CO2通量的时空变化规律,采用静态箱-红外CO2分析法研究了烟草团棵期、旺长期、平顶期、采收期及采收结束后共5个时期的垄体-烟株系统、垄间土壤及烟田生态系统CO2通量日变化特征。结果表明：垄体-烟株系统CO2通量具有明显的日变化特征（采收结束后除外）,通量变化呈＂U＂型分布,日间以吸收CO2为主,吸收高峰出现在12：00左右,夜间以排放为主,其呼吸通量与温度呈显著的正相关;采收结束后系统全天表现为CO2的净排放。垄间土壤CO2通量日变化呈单峰型,峰值出现在14：00左右,通量变化与土壤温湿度间存在显著的相关关系。整个烟田生态系统的CO2通量日变化规律与垄体-烟株系统趋于一致,通量日变化幅度及CO2日净吸收量随生育期表现不同,平顶期CO2通量日变化幅度最大,吸收峰值最高,为-2419.48 mg·m^-2·h^-1,CO2日净吸收量大小为平顶期〉采收期〉旺长期〉团棵期,表现为碳汇,而采收结束后则表现为碳源。

英文摘要：

In order to facilitate better understanding of spatial-temporal variation of CO2 fluxes in tobacco field ecosystem,diurnal variation of CO2 fluxes in the ridge-tobacco system,and the soil between ridges and the whole tobacco field ecosystem at five different tobacco growing stages（rosette stage,vigorous growing stage,flat stage,harvest stage,and after-harvest stage） were measured respectively by using a closed chamber technique（infrared CO2 analyzer）.Results showed that the ridge-tobacco system showed significant diurnal variation at all stages,except after-harvest stage,and CO2 fluxes curve presented a ＂U＂ pattern.In daytime the system mainly absorbed CO2,reaching peak at about 12：00,while at night it released CO2,and a significant positive correlation was found between rate of CO2 emission and temperature.At after-harvest stage,the system only showed CO2 emission in daytime.The diurnal variation of CO2 fluxes in soil between ridges showed a single peak curve,with peak at about 14：00.There was significant correlation between CO2 fluxes in soil between ridges and soil temperature and moisture at different depths.The diurnal variation of CO2 fluxes in the whole tobacco field ecosystem was consistent with that in the ridge-tobacco system.However,the range of CO2 fluxes variation and daily net absorption of CO2 fluxes were different at different growing stages.The maximal range of CO2 fluxes occurred at flat stage with maximum value of-2419.48 mg·m^-2·h^-1.Daily net absorption of CO2 amount at different growing stages was in the following order：flat stage〉harvest stage〉vigorous growing stage〉rosette stage.It was displayed in the form of carbon sink at the above four growing stages,and was regarded as carbon source at after-harvest stage.