降雨和施肥对上海崇明岛小麦田N2O排放的影响——基于涡度协方差法的研究  

Effects of Precipitation and Fertilization on N2O Discharge from Wheat Field in Chongming Island, Shanghai Estimated by Eddy Covariance Technology

作　　者：张梦珊 郭海强[1] 马俊[1] 李红[1] 戴圣骐 顾凯华 高伟 赵斌[1] ZHANG Mengshan;GUO Haiqiang;MA Jun;LI Hong;DAI Shengqi;GU Kaihua;GAO Wei;ZHAO Bin(Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering,Institute of Biodiversity Science,Fudan University,Shanghai Chongming Dongtan Wetland Ecosystem Research Station,Shanghai 200438,China;Shanghai Meteorological Service,Shanghai 202150,China;Yangtze River Delta Center for Environmental Meteorology Prediction and Warning,Shanghai 200030,China)

机构地区：[1]复旦大学生物多样性与生态工程教育部重点实验室,上海崇明东滩湿地生态系统国家定位观测研究站,崇明生态研究院,复旦大学,上海200438 [2]上海市崇明区气象局,上海202150 [3]长三角环境气象预报预警中心,上海200030

出　　处：《土壤》2019年第5期929-941,共13页Soils

基　　金：上海市科委科研项目(16ZR1431700);上海市科委崇明专项(15dz1208105)资助;国家自然科学基金项目(91637101);中国气象局大气探测重点开放实验室开放课题(KLAS201406)

摘　　要：在基于涡度协方差技术的小麦田N2O通量观测基础上,分析了小麦田N2O的排放动态以及不同时间尺度上降雨和施肥对小麦田N2O排放的影响,同时以增强回归树的方法定量分析了降雨和施肥相关因子对小麦田N2O通量的贡献率。结果表明:小麦田N2O通量没有明显的昼夜和季节变化模式,研究期内N2O平均日排放量为666.5μg/(m^2·d)±669.4μg/(m^2·d)(以N2O-N量计);N2O主要以脉冲的形式释放,其中降雨和施肥引发的脉冲占小麦田N2O总排放量的比例分别为29.4%、19.2%;降雨促进小麦田N2O排放,且N2O通量对降雨事件的响应比较迅速(主要集中在雨后的几小时内),同时降雨的影响能持续1~2 d;相比降雨,施肥对小麦田N2O排放的促进作用存在一周左右的时滞;综合考虑施肥和降雨的交互影响,在施肥后1~8 d内发生的降水事件对N2O的排放有明显的促进作用。因此,二者的交互影响不容忽视。As a major source of N2O emissions,cropland has been researched more,with precipitation and fertilization being considered as the natural and anthropogenic key factors that affecting N2O emissions in wheat fields,respectively.Given the low sampling frequency,most previous studies using the static chamber method may underestimate N2O emissions.Meanwhile,the potential interaction effect of precipitation and fertilization on cropland N2O emissions have been neglected.In this study,we reported the dynamics of N2O emissions and investigated the effects of precipitation and fertilization on N2O emission from wheat fields at different time scales based on the eddy covariance observation.Meanwhile,the Boosted Regression Trees method was adopted to quantify the precipitation and fertilization-related factors.The results showed that there were no obvious seasonal and diurnal variation patterns of N2O flux in wheat fields.The average daily N2O emission was N2O-N 666.5±669.4μg/(m^2·d)in this study,which was mainly released as a pulse.The ratios of precipitation and fertilization-induced pulses to total N2O emissions in wheat fields were 29.4% and 19.2%,respectively.Precipitation increased N2O emissions,and which responded rapidly to the precipitation events(mainly within a few hours after the precipitation).Meanwhile,the precipitation promotion could last 1–2 days.Fertilization also increased N2O emissions,but existed a one-week lag.Considering the interactive effects of precipitation and fertilization,precipitation events occurring within 1–8 days after fertilization significantly promoted the emission of N2O.Therefore,the interaction of precipitation and fertilization should not be neglected.

关 键 词：N2O通量 降雨 施肥 涡度协方差 

分 类 号：Q14[生物学—生态学]