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中高纬度森林地区由于气候条件变化剧烈,土壤温室气体排放量的估算存在很大的不确定性,并且不同碳氮气体通量的主控因子与耦合关系尚不明确。以长白山温带针阔混交林为研究对象,采用静态箱-气相色谱法连续4a(2005—2009年)测定土壤二氧化碳(CO2)、甲烷(CH4)和氧化亚氮(N2O)净交换通量以及温度、水分等相关环境因子。研究结果表明:温带针阔混交林土壤整体上表现为CO2和N2O的排放源和CH4的吸收汇。土壤CH4、CO2和N2O通量的年均值分别为-1.3 kg CH4hm-2a-1、15102.2 kg CO2hm-2a-1和6.13 kg N2O hm-2a-1。土壤CO2通量呈现明显的季节性规律,主要受土壤温度的影响,水分次之;土壤CH4通量的季节变化不明显,与土壤水分显著正相关;土壤N2O通量季节变化与土壤CO2通量相似,与土壤水分、温度显著正相关。土壤CO2通量和CH4通量不存在任何类型的耦合关系,与N2O通量也不存在耦合关系;土壤CH4和N2O通量之间表现为消长型耦合关系。这项研究显示温带针阔混交林土壤碳氮气体通量主要受环境因子驱动,不同气体通量产生与消耗之间存在复杂的耦合关系,下一步研究需要深入探讨环境变化对其耦合关系的影响以及内在的生物驱动机制。
Due to the dramatic changes in climate conditions in the middle and high latitudes of forest area, there is great uncertainty in the estimation of soil greenhouse gas emissions, and the relationship between the main control factors and the coupling of different carbon and nitrogen gas fluxes is not yet clear. Taking the temperate coniferous and broad-leaved mixed forest in Changbai Mountain as the research object, the net exchange fluxes of soil carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were determined by static box-gas chromatography , Water and other related environmental factors. The results showed that the temperate coniferous and broad-leaved mixed forest soil as a whole showed the emission sources of CO2 and N2O and the sink of CH4. The average annual CH4, CO2 and N2O fluxes were -1.3 kg CH4hm-2a-1, 15102.2 kg CO2hm-2a-1 and 6.13 kg N2O hm-2a-1, respectively. The soil CO2 flux showed a seasonal pattern, which was mainly affected by soil temperature followed by water. The seasonal change of soil CH4 flux was not obvious and positively correlated with soil moisture. The seasonal variation of soil N2O flux and soil CO2 flux Similar to that of soil moisture and temperature. Soil CO2 flux and CH4 flux do not exist any type of coupling relationship, and N2O flux does not exist the coupling relationship between the soil CH4 and N2O flux showed the relationship between the growth and decline. This study shows that soil carbon and nitrogen fluxes in temperate coniferous and broad-leaved mixed forests are mainly driven by environmental factors and that there is a complicated coupling relationship between different gas fluxes and their consumption. The next step needs further study on the impact of environmental changes on their coupling relations As well as the inherent biological drive mechanism.