温带针阔混交林土壤碳氮气体通量的主控因子与耦合关系  

The controlling factors and coupling of soil CO_2,CH_4 and N_2O fluxes in a temperate needle-broadleaved mixed forest

作　　者：党旭升[1,2] 程淑兰[2] 方华军[1] 于贵瑞[1] 韩士杰[3] 张军辉[3] 王淼[3] 王永生[1] 徐敏杰[2] 李林森[2] 王磊[1] 

机构地区：[1]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室,北京100101 [2]中国科学院大学,北京100049 [3]中国科学院沈阳应用生态研究所,沈阳110016

出　　处：《生态学报》2015年第19期6530-6540,共11页Acta Ecologica Sinica

基　　金：国家自然科学基金(31290221;41471212;31470558;31290222;31130009);国家重点基础研究发展计划项目(2012CB417103);中国科学院地理科学与资源研究所"秉维"优秀青年人才基金(2011RC202);中国科学院战略性先导科技专项(XDA05050600)

摘　　要：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。Carbon dioxide（ CO2）,methane（ CH4） and nitrous oxide（ N2O） are three major greenhouse gases,accounting for 80% of global warming. Forest ecosystems comprise the largest carbon stocks in terrestrial ecosystems,and function as important sinks and sources of atmospheric CO2,CH4 and N2O. Complicated interactions occur during the generation and absorption of soil CO2, CH4 and N2O, including synergies, tradeoffs, and randomness. High-latitude forests areexperiencing the effects of significant global change（ e. g.,warming,changed precipitation,and increased nitrogen deposition）,leading to great uncertainty in estimates of soil greenhouse gas fluxes. Furthermore,the factors controlling the coupling of soil CO2,CH4 and N2O fluxes remain unclear. This study was conducted in the temperate needle-broadleaved mixed forest of Changbai Mountain,Northeast China. The net exchange fluxes of soil CO2,CH4 and N2O,as well as soil temperature and soil moisture,were measured over four years（ 2005 – 2009） using static chamber and gas chromatograph techniques. The results showed that temperate needle-broadleaved mixed forest soils behaved as a source of atmospheric CO2 and N2O but a sink of atmospheric CH4 over the course of the study. The average soil CH4,CO2 and N2O fluxes were estimated at-1.30 kg CH4hm-2a-1,15102.2 kg CO2hm-2a-1,and 6.13 kg N2 O hm-2a-1,respectively. In addition,soil CO2 flux exhibited significant seasonality,and was mainly affected by soil temperature,followed by soil moisture. Seasonal variation in soil CH4 flux was less significant than that of soil CO2 and N2O fluxes; moreover,it was positively correlated with soil moisture. When soil temperatures were within a threshold range,soil moisture determined CH4 production and oxidation in soil profiles by regulating CH4 and O2diffusion as well as methanotrophic community activity. Similar to soil CO2 flux,soil N2 O flux was significantly correlated with soil moisture and soil temperature. Furthermore,there were no significant relationships between

关 键 词：土壤CO2通量 土壤CH4通量 土壤N2O通量 主控因子 耦合关系 

分 类 号：S714[农业科学—林学]