长期氮添加和降水格局改变对高寒草原CH4通量的影响  

Effects of long-term nitrogen addition and precipitation changes on CH4flux in an alpine steppe

作　　者：杨阳 肖元明 李长斌 高永恒[4] 李春丽 周国英[1] YANG Yang;XIAO Yuanming;LI Changbin;GAO Yongheng;LI Chunli;ZHOU Guoying(Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810008,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Agriculture and Animal Husbandry,Qinghai University,Xining 810016,China;Chengdu Institute of Biology,Chinese Academy of Sciences,Chengdu 610041,China;State Key Laboratory of Plateau Ecology and Agriculture,Qinghai University,Xining 810016,China)

机构地区：[1]中国科学院西北高原生物研究所,西宁810008 [2]中国科学院大学,北京100049 [3]青海大学农牧学院,西宁810016 [4]中国科学院成都生物研究所,成都610041 [5]青海大学省部共建三江源生态与高原农牧业国家重点实验室,西宁810016

出　　处：《应用与环境生物学报》2022年第6期1542-1548,共7页Chinese Journal of Applied and Environmental Biology

基　　金：青海省自然科学基金项目(2019-ZJ-910);青海省自然科学基金项目(2019-ZJ-935Q)资助;青海省国际交流合作项目资助(2019-HZ-807)。

摘　　要：土壤是甲烷(CH4)重要的源和汇.氮沉降和降水格局变化正在急剧改变土壤碳循环,进而可能对土壤CH4通量造成深刻影响.高寒生态系统是巨大的碳库,对氮沉降和降水变化十分敏感.然而,目前多数研究集中在短期实验上,缺乏对长期氮沉降和降水变化背景下CH4通量的响应及其调控因素的认识.以青藏高原高寒草原为研究对象,在2013年搭建模拟氮沉降和降水格局改变实验平台.基于静态箱–气相色谱法测定2020年生长季(5-10月)土壤CH4通量.结果显示,高寒草原土壤呈CH4的汇.氮添加没有显著改变生长季和植物生长高峰CH4通量.然而,降水变化显著改变了生长季和植物生长高峰CH4通量,其中降水增加(+50%降水)降低了CH4的吸收(分别为–16%和–45%),降水减少(–50%降水)增强了CH4的吸收(分别为+73%和+33%).进一步研究发现,与植物属性和功能基因丰度相比,土壤环境因子主导了CH4通量变化(解释率>90%).其中CH4通量与土壤含水量和温度显著正相关,与土壤pH显著负相关.综上所述,在未来全球变化情景下,降水格局改变更能调节青藏高原高寒草原CH4通量的变化.(图6表1参37)Soil is an important source and sink of methane(CH4). Atmospheric nitrogen deposition and precipitation changes rapidly alter the soil carbon cycle, which may have a profound impact on soil CH4flux.Alpine ecosystems are critical carbon reservoirs that are sensitive to changes in nitrogen deposition and precipitation. The influence of long-term nitrogen deposition and precipitation changes on CH4flux remains unknown. To help fill these knowledge gaps, we established an experimental platform to simulate nitrogen deposition and precipitation changes in the alpine steppe of the Qinghai-Tibetan Plateau in 2013. We measured the CH4flux during the growing season in 2020(May-October) using static chamber gas chromatography. Our results revealed that alpine steppe acts as a CH4sink. The addition of nitrogen did not significantly alter CH4flux during the growing season or peak plant growth. However, the precipitation changes significantly altered CH4flux during the growing season and peak plant growth, during which an increase in precipitation(by 50%),decreased the CH4uptake(by-16% and-45%, for growing season and peak plant growth respectively), and a decrease in precipitation( by-50%) increased the CH4uptake(+73% and +33%, for growing season and peak plant growth respectively). Further investigation revealed that soil environmental factors dominantly regulated the variation in CH4flux(explanation > 90%) compared with plant attributes and functional gene abundance.CH4flux was significantly positively correlated with soil moisture content and temperature and negatively correlated with soil pH. Overall, these results indicate that precipitation patterns can better regulate the changes in CH4flux in the alpine steppe under future global climatic changes.

关 键 词：氮沉降 降水变化 温室气体 高寒草原 青藏高原 

分 类 号：S812[农业科学—草业科学]