氮素类型和剂量对寒温带针叶林土壤N2O排放的影响

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 氮素类型和剂量对寒温带针叶林土壤N2O排放的影响 DOI: 10.5846/stxb201508041639 作者: 作者单位: 中国科学院地理科学与资源研究所,中国科学院大学资源与环境学院,中国科学院地理科学与资源研究所,中国科学院地理科学与资源研究所,中国科学院大学资源与环境学院,中国科学院地理科学与资源研究所,中国科学院地理科学与资源研究所,中国科学院大学资源与环境学院,中国科学院大学资源与环境学院 作者简介: 通讯作者: 中图分类号: Q142 基金项目: 国家自然科学基金项目（41471212，31470558，31290221，31130009，31290222）；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”优秀青年人才基金项目（2011RC202）；中国科学院战略性先导科技专项（XDA05050600） The effects of types and doses of nitrogen addition on soil N2O flux in a cold-temperate coniferous forest, northern China Author: Affiliation: Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographical Sciences and Natural Resources Research,Chinese Academy of Sciences,College of Resources and Environment,University of Chinese Academy of Sciences,Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographical Sciences and Natural Resources Research,Chinese Academy of Sciences,Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographical Sciences and Natural Resources Research,Chinese Academy of Sciences,College of Resources and Environment,University of Chinese Academy of Sciences,Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographical Sciences and Natural Resources Research,Chinese Academy of Sciences,Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographical Sciences and Natural Resources Research,Chinese Academy of Sciences,College of Resources and Environment,University of Chinese Academy of Sciences,College of Resources and Environment,University of Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:大气氮沉降输入会增加森林生态系统氮素有效性，进而改变土壤N2O产生与排放，然而有关不同氮素离子（氧化态NO3--N与还原态NH4+-N）沉降对土壤N2O排放的影响知之甚少。以大兴安岭寒温带针叶林为研究对象，构建了3种类型（NH4Cl、KNO3、NH4NO3）和4个施氮水平（0、10、20、40 kg N hm-2 a-1）的增氮控制试验，利用流动化学分析仪和静态箱-气相色谱法4次/月测定凋落物层和矿质层土壤无机氮含量、土壤-大气界面N2O净交换通量以及相关环境因子，分析施氮类型和剂量对土壤氮素有效性、土壤N2O通量的影响，探讨氮素富集条件下土壤N2O通量的环境驱动机制。结果表明：施氮类型和剂量均显著影响土壤无机氮含量，土壤NH4+-N的积累效应显著高于NO3--N。施氮一致增加寒温带针叶林土壤N2O排放，NH4NO3促进效应最为明显，增幅为442%-677%，高于全球平均水平（134%）。土壤N2O通量与土壤温度、凋落物层NH4+-N含量正相关，且随着施氮水平增加而增加。结果表明大气氮沉降短期内不会导致寒温带针叶林土壤NO3--N大量流失，但会显著促进土壤N2O的排放。此外，外源性NH4+和NO3-输入对土壤N2O排放的促进作用具有协同效应，在未来森林生态系统氮循环和氮平衡研究中应该区分对待。 Abstract:Increasing atmospheric nitrogen (N) deposition would change soil N availability, and thereby changes N2O production and emission from N-limiting forest soils. However, it is still unclear about the contrasting effects of different N ion (i.e., oxidized NO3--N and reduced NH4+-N) deposition on soil N2O emission in boreal forests. In the present study, a cold-temperate coniferous forest in the Great Khingan region was selected for conducting the manipulative N addition experiment, including three forms of N fertilizers (NH4Cl, KNO3, and NH4NO3) and four rates of N addition (0, 10, 20, and 40 kg N hm-2 a-1). Soil-atmospheric N2O exchanging fluxes were measured four times per month using static chamber-gas chromatography. Simultaneously, soil temperature, moisture, and inorganic N contents were measured to explore how the main factors affect soil N2O emission. The results showed that the types and doses of N addition significantly changed soil inorganic N contents, and the accumulation of soil NH4+-N was significantly higher than that of soil NO3--N due to N addition. N addition increased N2O emission from the boreal forest soil, and the NH4NO3 addition treatments promoted high soil N2O fluxes, with an increase of 442% to 667%, which was higher than the global average (134%). There were positive correlations between soil N2O fluxes and soil temperature, and between soil N2O fluxes and soil NH4+-N contents in the litter layer. Soil N2O fluxes were driven by soil temperature, followed by soil NH4+-N contents in the litter layer. These findings suggest that atmospheric N deposition cannot lead to a significant soil NO3--N leaching and loss in boreal forests over the short term, but it can significantly promote soil N2O emission. Furthermore, exogenous NH4+ and NO3- inputs into boreal forests have synergic effects on soil N2O emission, which should be distinguished in N cycle and balance in terrestrial ecosystems using 15N tracer methods in the future. 参考文献 相似文献 引证文献