大气CO2浓度升高对湿地植物生物量和土壤活性有机碳的影响.docVIP

CO2浓度升高对湿地植物生物量和土壤活性有机碳的影响 赵光影1,2,刘景双1,李春艳3, 王洋1,窦晶鑫1,2 (1.中国科学院 东北地理与农业生态研究所，吉林 长春 130012；2.中国科学院 研究生院，北京 100049； 3.哈尔滨师范大学环境科学研究所，黑龙江 哈尔滨 150080) 摘要:利用开顶箱薰气室(Open-Top Chamber),设置正常大气CO2浓度(AC,350μmol·mol-1)和高CO2浓度(EC,700μmol·mol-1)2个水平和不施氮(NN,0gN·m-2)、常氮(MN,5gN·m-2)和高氮(15gN·m-2)3个氮素水平,研究不同氮素水平下CO2浓度升高对小叶章(Calamagrostis angustifolia)生物量和土壤活性有机碳的影响.结果表明,CO2浓度升高对小叶章生物量的影响因生长期而异.大气CO2升高对小叶章地上生物量的促进作用主要表现在生长前期,拔节期和抽穗期地上生物量较正常大气CO2含量增加12.42%～27.04%,而腊熟期和成熟期仅增加3.11%～11.48%;大气CO2升高对小叶章地下生物量的促进作用在生长后期表现明显,除拔节期外,小叶章地下生物量增加17.68%～42.19%.CO2浓度升高使不同N处理根固定碳量占植株总体碳库比例均不同程度的增加,各生长期平均分别增加2.75%,2.96%和4.92%.CO2浓度升高条件下,就不同生长期不同N处理平均值而言,土壤各活性有机碳除CHC保持不变外,其余均呈增加趋势,增幅为MBC(5.98%)＞LBC(4.14%)＞DOC(1.20%).土壤各活性有机碳与植物参数逐步回归分析表明,MBC,LBC和CHC与地下生物量具有较强的相关性;DOC则与地上生物量呈弱相关.高CO2浓度导致的根系生物量增加和碳分配比例提高是土壤活性有机碳含量增加的主要原因. 关键词:CO2浓度升高; 湿地; 生物量; 活性有机碳 中图分类号 X144 文章编号 文献标识码A ZHAO Guang-ying1,2,LIU Jing-shuang1,LI Chun-yan3,WANG Yang1,DOU Jing-xin12 Effects of elevated CO2 on biomass and soil active carbon in freshwater marsh Journal of Beijing Forestry University [23ref] 1.Northeast Institute of Geography and Agroecology, Chinese Academy of Science, Changchun 130012, China 2.Graduate School,Chinese Academy of Sciences, Beijing 100049, China 3.Harbin Normal of University, Harbin 150080,China An experiment was carried out with treatments different in nitrogen supply (0,5,15 g?m-2) and CO2 level(350 vs 700μmol·mol-1) on the OTCs (open top chamber) equipment to investigate the biomass of Calamagrostis angustifolia and marsh soil active organic carbon. Results showed that the impacts of elevated CO2 on biomass differed in each gowth stage. The boosting effect of CO2 enrichment on aboveground biomass was revealed in early growth stage. Elevated CO2 concentration had increased aboveground biomass by 12.42%～27.04% during the jointing and heading stage with all the nitrogen supply treatments. And the increase were 3.11%～11.48% during dough and maturity stage. The response of belowground biomass to eleva