不同土壤水分含量下高寒草地CH_4释放的比较研究  

Comparative study on methane emissions from alpine grasslands with different soil water content.

作　　者：胡启武[1] 吴琴[1] 李东[1] 曹广民[1] 

机构地区：[1]中国科学院西北高原生物研究所

出　　处：《生态学杂志》2005年第2期118-122,共5页Chinese Journal of Ecology

基　　金：中国科学院知识创新重大项目 (KZCX1-SW -0 1-0 1B);国家自然科学基金资助项目 (4 0 47113 3 )。

摘　　要：20 0 3年 6月 30日～ 9月 4日 ,利用密闭箱 气相色谱法 ,对发育于不同水分状况下的灌丛草甸(GC)、矮嵩草草甸 (AC)、藏嵩草草甸 (ZC)和季节性湿地 (SD)的CH4释放速率进行了比较研究。结果表明 ,观测期间 ,季节性湿地处于淹水状态 ,其它三种土壤平均水分含量分别为 39 6 %(GC)、38 4%(AC)、6 5 9%(ZC) ,而CH4平均释放速率分别为 - 0 0 31± 0 0 30 (GC)、- 0 0 2 6± 0 0 1 8(AC)、1 1 0 3±0 2 4 0 (ZC)和 6 92 2± 4 5 98mg·m-2 ·h-1 (SD) ,随着土壤水分含量的增加 ,高寒草地土壤CH4释放由吸收转为排放 ,表现出与土壤湿度很好的一致性。矮嵩草草甸不同处理CH4吸收强度AC <AJ <AL ,它们之间的差异除与土壤水分有关 ,还可能与处理引起的CH4传输途径不同有关。实验期间 ,矮嵩草草甸和灌丛草甸土壤 植物系统分别吸收CH438 6 9和 4 6 1 3mg·m-2 ,是大气温室气体CH4的弱汇 ,藏嵩草草甸和季节性湿地则是大气温室气体CH4的源 ,分别排放CH41 6 4 1和 1 0 30 g·m-2 。From 30 June to 4 September in 2003,using close chamber-GC method,comparative study on methane emissions was conducted in Potentilla fruticosa scrub meadow,Kobresia humilis meadow,Kobresia tibetica meadow as well as seasonal wetland,whose soil moistures varied from 38.4% to 100%.The results indicated that average methane emission rate differed in various treatments,with value of -0.031±0.030 mg·m -2·h -1 for GC,-0.026±0.018 mg·m -2·h -1 for AC,1.103±0.240 mg·m -2·h -1for ZC,and 6.922±4.598 mg·m -2·h -1for SD,respectively.Coinciding with soil moisture increase,alpine grasslands changed from methane emission to absorbing.Furthermore,methane absorbing varied in different treatments in Kobresia humilis meadow,in order of AC<AJ<AL.Besides soil moisture,the difference of methane transport pathway caused by treatments may be another reason for the differences of emission rates of AC,AJ,and AL.The results also showed that Kobresia humilis meadow and Potentilla fruticosa scrub meadow acted as weak methane sink during experiment period.The soil-plant systems of both meadows absorbed 38.69 mg·m -2,and 46.13 mg·m -2 CH_4,respectively.Mean while,Kobresia tibetica meadow and seasonal wetland acted as methane source,with 1.641 g·m -2 and 10.30 g·m -2 CH_4,respectively.

关 键 词：CH4 土壤水分含量 高寒草甸 密闭箱 

分 类 号：S812[农业科学—草业科学]