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题名: 农业活动对大气含氮气体的影响
作者: 张圆圆
学位类别: 博士
答辩日期: 2012
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 牟玉静
关键词: N2O ; N2O ; NOX ; NOX ; NH3 ; NH3 ; 秸秆还田 ; straw returning ; 替代肥 ; alternative fertilizer
其他题名: The influence of agricultural activities on atmospheric nitrogenous gases
中文摘要:       土壤是大气N2O、NOX和NH3的一个重要来源,尤其是耕作强度高、氮肥施用量大的农田土壤。本研究以长江三角洲大蒜地和华北平原玉米-小麦田为研究对象,系统地研究了这些地区农田土壤N2O、NOX和NH3的交换通量及其影响因素,并对华北平原玉米-小麦田NO和N2O的产生机理进行了深入研究,获得了以下主要研究成果: (1) 对国产GC-ECD仪器进行了改进,仪器测定N2O的精度由原来的>1%提高到0.31%,克服了CO2浓度对N2O测定的干扰,并且ECD的响应与N2O浓度间呈很好的线性相关性(R2=0.9996),确保了单点校正方法的可靠性。 (2) 发现华北平原玉米-小麦田约80%的N2O排放集中在现有化肥(复合肥和尿素)使用后的10天内;玉米季N2O排放量约占全年总排放的57%-86%;长期使用秸秆还田会大大促进农田N2O的排放;N2O排放存在显著性年际差异。认识到农田土壤温度是导致N2O显著季节性差异的主要影响因素,而土壤湿度是造成N2O年际差异及秸秆还田高排放的主要影响因子。 (3) 发现华北农田现有化肥的施用在玉米季可极大地促进NO和NH3的排放,而秸秆还田可以抑制NO和NH3的排放。华北农田季节性NO和NH3的高排放可能对区域光氧化剂O3和细粒子形成具有重要贡献。 (4) 基于NO和N2O排放的摩尔比值(NO/N2O),推测华北农田NO和N2O排放主要来源于施肥后短期内土壤的硝化作用,并被硝态肥与铵态肥的对比实验以及硝化抑制剂(双氰胺)的添加实验所证实。在玉米-小麦全年耕作期内,采用硝态肥替代现用铵态肥可分别减少54%和100%的N2O和NO排放。 (5) 华北农田模拟实验发现NO2-与NO3-耦合机制可极大促进N2O排放,土样培养实验发现NO2-对N2O还原酶具有显著抑制作用。因此,我们推测华北农田铵态肥施用后可快速通过硝化过程产生大量NO2-和NO3-,而NO2-对N2O还原酶的抑制作用导致了土壤施肥后N2O的高排放。
英文摘要:
      Soil is one of the major sources for atmospheric N2O, NOX and NH3, especially for the agricultural soil with extensive management and high nitrogen fertilizer application. In this study, N2O, NOX and NH3 exchange fluxes from garlic field in the Yangtze Delta and maize-wheat rotation field in the North China Plain (NCP) were measured, and the influence factors were investigated. In addition, the mechanisms for N2O and NO emissions from maize-wheat field in the NCP were researched. The main results were obtained as following: (1) The domestic GC-ECD instrument was improved, and the instrument precision was increased from >1% to 0.31%. The method overcame the influence of CO2 concentration on N2O measurement. Good linear correlation (R2=0.9996) between the response of the improved ECD and N2O concentrations ensured the reliability of the single point correction method. (2) About 80% of N2O emission from the maize-wheat field in the NCP occurred after 10 days of the applications of the local fertilizer (compound fertilizer and urea), and the N2O emissions in the maize seasons accounted for 57%-86% of the total emissions of each year. Straw returning promoted obviously N2O emission in the long-term period. Large N2O yearly variations were found. We recognized that the soil temperature was a key influence factor for the N2O seasonal difference, and the inter-annual variations and the high N2O emissions from straw returning were ascribed to the soil moisture. (3) The current N-fertilizers used in the NCP could greatly promoted NO and NH3 emissions from the maize field, while straw returning to the field could greatly reduce NO and NH3 emissions. The high N2O seasonal emissions from the field probably had important contributions to the formations of regional photo oxidant O3 and fine particles. (4) We inferred that the N2O and NO emissions in the NCP were mainly from the nitrification during the short fertilization periods based on the molar ratio of NO/N2O, which was confirmed by the experiments of replacing ammonium with nitrate fertilizer and addition with the nitrification inhibitor (DCD). Replacing ammonium with nitrate fertilizer could decrease 54% and 100% of N2O and NO emissions from the whole maize-wheat season, respectively. (5) The simulated experiment of the agriculture soil in the NCP showed that the coupling mechanism of NO2- and NO3- could greatly promoted N2O emission. The soil incubation experiment indicated that NO2- could significantly inhibit the activity of N2O reductase. Therefore, we inferred that large amounts of NO2- and NO3- could be quickly produced after the application of ammonium fertilizer by nitrification, and the inhibition of NO2- formed to N2O reductase resulted in high N2O emission from the maize-wheat soil after ammonium fertilization.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/35128
Appears in Collections:大气环境研究室_学位论文

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Recommended Citation:
张圆圆. 农业活动对大气含氮气体的影响[D]. 北京. 中国科学院研究生院. 2012.
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