森林土壤氧化亚氮排放对大气氮沉降增加的响应研究进展  

STUDY ON THE RESPONSES OF NITROUS OXIDE EMISSION TO INCREASED NITROGEN DEPOSITION IN FOREST SOILS: A REVIEW

作　　者：方华军[1] 程淑兰[2] 于贵瑞[1] 王永生[1] 徐敏杰[2] 党旭升[1] 李林森[2] 王磊[1] 李晓玉[1] 司高月 

机构地区：[1]中国科学院地理科学与资源研究所,生态系统观测与模拟重点实验室,北京100101 [2]中国科学院大学资源与环境学院,北京100049

出　　处：《土壤学报》2015年第2期262-271,共10页Acta Pedologica Sinica

基　　金：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)资助

摘　　要：森林土壤N2O来源于土壤氮素的氧化还原反应,硝化、反硝化、硝化细菌反硝化以及化学反硝化是其产生的四个关键过程。当前,氮素富集条件下森林土壤N2O排放存在硝化和反硝化主导作用之争,对大气氮沉降增加的响应模式以及微生物驱动机制尚不清楚。综述了森林土壤N2O来源的稳定性同位素拆分,森林土壤总氮转化和N2O排放对增氮的响应规律,增氮对N2O产生菌群落活性和组成的影响,并指出研究的薄弱环节与未来的研究重点。总体而言,森林土壤N2O排放对大气氮沉降增加的响应呈现非线性,包括初期无明显响应、中期缓慢增加和后期急剧增加三个阶段,取决于森林生态系统"氮饱和"程度。施氮会引起森林土壤有效氮由贫氮向富氮的转变,相应地改变了土壤硝化细菌和反硝化细菌群落丰度与组成,进而影响土壤N2O排放。由于森林土壤N2O排放监测、土壤总氮转化和N2O产生菌群落动态研究多为独立进行的,难以阐明微生物功能群与N2O排放之间的耦合关系。未来研究应该有机结合15N-18O标记和分子生物学技术,准确量化森林土壤N2O的来源,揭示森林土壤N2O排放对增氮的非线性响应机理。Continuous accumulation of nitrous oxide （N2O） in the atmosphere leads to global warming and ozone depletion. Forest ecosystems act as source and sink of atmospheric N2O, posing a great uncertainty in budgeting of atmospheric N2O. Exogenous nitrogen inputs into terrestrial ecosystems are an alternative explanation for this uncertainty. Therefore, exploring mechanisms involved in responses of N2O emission from forest soils to increased atmospheric nitrogen deposition is of some important theoretical and practical significance. However, due to complexity of soil nitrogen cycling and high spatial heterogeneity of forest ecosystems, progress of the research on soil N2O flux response to N addition has been quite slow. N2O emission in forest soils is mediated by microbial communities, and nitrification, denitrifieation, nitrifler denitrification and chemical denitrification are the four main processes of soil N2O production. Presently, which one of nitrification and denitrificatiopn is the leading contributor to soil N2O emission under nitrogen enrichment is still controversial; and how N2O emission responds to increased N deposition and what mechanism is involved in soil microbes driving the porcess are not well known. In this paper, a review is presented of the progresses of the study on identification ofsources of N2O in forest soils using the stable isotope labelling technique, laws of the responses of total N transformation in and N2O emission from forest soils to nitrogen addition, as well as effects of increased N depostion on activity and composition of soil microbial community. Also, the paper points out weak links in the present studies and possible research priorities in the future. Generally, soil N2O flux is influenced by many environmental factors including soil temperature, soil moisture, pH, Eh, and N availability. Increased nitrogen deposition may increase, decrease or have little effect on forest soil N2O emission, depending on forest types, initial nitrogen content in soils, and dose and duration

关 键 词：大气氮沉降 氧化亚氮排放 硝化细菌 反硝化细菌 同位素标记 分子生物学 

分 类 号：Q154[生物学—普通生物学]