旱地生态系统碳氮过程对干旱响应与反馈的Meta分析  

A meta-analysis of response and feedback of terrestrial carbon and nitrogen cycling to drought

作　　者：郑雅晶 邹建文 刘树伟 ZHENG Yajing;ZOU Jianwen;LIU Shuwei(College of Resources and Environmental Sciences/Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation,Nanjing Agricultural University,Nanjing 210095)

机构地区：[1]南京农业大学资源与环境科学学院/江苏省低碳农业与温室气体减排重点实验室,南京210095

出　　处：《南京信息工程大学学报（自然科学版）》2022年第1期1-10,共10页Journal of Nanjing University of Information Science & Technology（Natural Science Edition）

基　　金：国家自然科学基金(41771268,41225003,41771323)。

摘　　要：干旱会影响陆地生态系统碳氮循环,形成对气候变化的反馈效应.然而,目前国际上有关旱地生态系统碳氮过程对干旱的响应与反馈效应尚不清楚.本研究共收集整理了全球来自128篇文献的1344组原位观测数据进行Meta分析(Meta-analysis),用以定量评估旱地生态系统碳氮过程对干旱的响应程度和反馈效应.结果表明,干旱会显著降低植被碳库,且地上生物量碳对干旱的敏感性略高于地下生物量碳.土壤CO_(2)和N_(2)O排放在干旱条件下均显著减少.对于土壤碳氮库,干旱条件下,土壤有机碳库和氮库均无显著变化,相反,土壤可溶性有机碳库显著降低,土壤NO_(3)^(-)-N含量显著增加.此外,干旱还会导致净生态系统生产力(NEP)显著降低.本研究首次将干旱对土壤CO_(2)和N_(2)O排放的影响与植被和土壤碳氮库的变化联系起来,并得出以下结论:干旱虽会引起土壤碳排放减少,但由于其同时也会抑制植被的生长,导致在未来干旱的气候条件下,加剧旱地生态系统对气候变化的正反馈效应.Drought has been shown to alter terrestrial ecosystem carbon(C)and nitrogen(N)dynamics,and thus feedback to future climate.However,drought-induced changes in terrestrial upland C and N pools and the drought response of soil carbon dioxide(CO_(2))and nitrous oxide(N_(2)O)fluxes are yet to be quantified.A meta-analysis was conducted that compiled 1344 measurements from 128 manipulative studies worldwide to obtain a general picture of terrestrial C and N cycling responses to soil drought stress and identify the primary driving factors.We showed that drought significantly decreased plant C pools,with stronger negative responses of aboveground than belowground C components.Drought significantly decreased soil CO_(2) and N_(2)O fluxes.There were non-significant changes in soil organic C and N pools in response to drought;in contrast to a considerable decrease in soil dissolved organic C,there was a robust increase in soil NO_(3)^(-)-N following short-term drought impact.Furthermore,drought also significantly decreased Net Ecosystem Productivity(NEP).Our study provides insights into soil release of CO_(2) and N_(2)O with a linkage to the changes in terrestrial C and N pools in response to drought across upland biomes.Our findings highlight that,despite the lowered soil C release rate,the capacity of upland biomes as a C sink to slow climate change would still be weakened in a future drier climate.

关 键 词：气候变化 干旱 META分析 CO_(2) N_(2)O 土壤碳库 土壤氮库 

分 类 号：S153[农业科学—土壤学] X71[农业科学—农业基础科学]