A primary study of nitrous oxide emission in agriculture region of Northern China

Significance of nitrous oxide in atmospheric chemistry is reviewed briefly. Background concentration of N2O at Wudaoliang in Qinghai Province of Western China has been measured by collecting gas samples and analysing them with electron capture-gas chromatography. The atmospheric concentration fluctuates in the range of 303-315 ppb with the mean value of 308 ppb. The emission rate of N2O in agriculture region of Northern China has been studied primarily. Fertilization, rain and temperature of soil appear conductible to N2O emission. The interactions between greenhouse effect and N2O emission have been discussed. The catalytic action of N2O in stratospheric ozone depletion processes and the effect of high N2O concentration on ozone depletion in stratosphere have been considered and discussed.     

Greenhouse gas abatement strategies for animal husbandry

Agriculture contributes significantly to the anthropogenic emissions of non-CO₂ greenhouse gases methane and nitrous oxide. In this paper, a review is presented of the agriculture related sources of methane and nitrous oxide, and of the main strategies for mitigation. The rumen is the most important source of methane production, especially in cattle husbandry. Less, but still substantial, amounts of methane are produced from cattle manures. In pig and poultry husbandry, most methane originates from manures. The main sources of nitrous oxide are: nitrogen fertilisers, land applied animal manure, and urine deposited by grazing animals. Most effective mitigation strategies for methane comprise a source approach, i.e. changing animals’ diets towards greater efficiencies. Methane emissions, however, can also be effectively reduced by optimal use of the gas produced from manures, e.g. for energy production. Frequent and complete manure removal from animal housing, combined with on-farm biogas production is an example of an integrated on-farm solution. Reduced fertiliser nitrogen input, optimal fertiliser form, adding nitrification inhibitors, land drainage management, and reduced land compaction by restricted grazing are the best ways to mitigate nitrous oxide emissions from farm land, whereas, management of bedding material and solid manure reduce nitrous oxide emissions from housing and storage. Other than for methane, mitigation measures for nitrous oxide interact with other important environmental issues, like reduction of nitrate leaching and ammonia emission. Mitigation strategies for reduction of the greenhouse gases should also minimize pollution swapping.     

硝化抑制剂对我国蔬菜生产产量、氮肥利用率和氧化亚氮减排效应的影响:Meta分析

我国蔬菜生产系统由于长期过量施肥导致氮肥利用率低和环境问题严重,氮肥配施硝化抑制剂是降低活性氮损失、增加蔬菜产量和提高氮肥利用率的有效策略,然而缺乏系统研究.基于数据整合分析的方法,系统分析了氮肥配施硝化抑制剂［双氰胺（DCD）、3,4-二甲基吡唑磷酸盐（DMPP）和2-氯-6-三氯甲基吡啶（NP）］对我国蔬菜生产的产量、植株氮吸收、氮肥利用率和氧化亚氮减排效应的影响,进一步揭示不同田间管理措施对其效果的影响.结果表明,氮肥配施硝化抑制剂能够显著提高蔬菜产量（9.2%）、植株氮吸收（10.4%）和氮肥利用效率（11.2%）,同时减少氧化亚氮排放（28.4%）.不同硝化抑制剂类型中,NP对增产效应和氧化亚氮减排效应的影响幅度最高,分别为16.1%和32.0%,其次是DMPP和DCD.硝化抑制剂在不同氮肥用量中能提高蔬菜产量（6.7%~14.7%）和减少氧化亚氮排放（14.6%~36.8%）.在中性和碱性菜地土壤中,硝化抑制剂的增产效应和氧化亚氮减排效应的影响幅度较酸性土大.硝化抑制剂在露地栽培、根菜类和叶菜类的条件下对产量的增加和氧化亚氮的减排效果较好.主成分分析表明,土壤总氮含量和土壤pH是影响硝化抑制剂对蔬菜产量形成和驱动氧化亚氮排放的主要因素.综上,硝化抑制剂是实现蔬菜系统提质增效、节肥减排的重要举措.同时,农户应根据土壤和田间管理措施选择适宜硝化抑制剂类型,以最大限度提高其有效性.     

Greenhouse gas emissions from covered slurry compared with uncovered during storage

Liquid manure storage facilities are sources of methane, nitrous oxide and ammonia emissions. Different materials for covering liquid manure storage facilities to reduce gaseous emissions were investigated on laboratory scale (65 l): perlite (Pegülit™), lightweight expanded clay aggregate (Leca™) and chopped straw—both individually and combined with lactic acid or saccharose, respectively. Methane is the predominant greenhouse gas emitted from liquid manure storage facilities. Nitrous oxide plays a role when surfaces become encrusted when it occurs by using the cover materials investigated. Common cover materials have good reduction effects on ammonia but less on greenhouse gas emissions. Straw can increase emissions of methane and nitrous oxide, as can granules. Lowering the pH value of the slurry can reduce both methane and nitrous oxide emissions. Combinations of covering and acidifying should cause a pH value below 6.0 to reduce methane and nitrous oxide emissions effectively. Lower pH value seems to be necessary also to reduce ammonia emissions effectively.     

Climate change impacts on freshwater recreational fishing in the United States

We estimated the biological and economic impacts of climate change on freshwater fisheries in the United States (U.S.). Changes in stream temperatures, flows, and the spatial extent of suitable thermal habitats for fish guilds were modeled for the coterminous U.S. using a range of projected changes in temperature and precipitation caused by increased greenhouse gases (GHGs). Based on modeled shifts in available thermal habitat for fish guilds, we estimated potential economic impacts associated with changes in freshwater recreational fishing using a national-scale economic model of recreational fishing behavior. In general, the spatial distribution of coldwater fisheries is projected to contract, being replaced by warm/cool water and high-thermally tolerant, lower recreational priority (i.e., “rough”) fisheries. Changes in thermal habitat suitability become more pronounced under higher emissions scenarios and at later time periods. Under the highest GHG emissions scenario, by year 2100 habitat for coldwater fisheries is projected to decline by roughly 50 % and be largely confined to mountainous areas in the western U.S. and very limited areas of New England and the Appalachians. The economic model projects a decline in coldwater fishing days ranging from 1.25 million in 2030 to 6.42 million by 2100 and that the total present value of national economic losses to freshwater recreational fishing from 2009 to 2100 could range from $81 million to $6.4 billion, depending on the emissions scenario and the choice of discount rate.     

同步硝化反硝化过程中污染物的去除及温室气体的释放

采用缺氧-好氧SBR反应器,研究了同步硝化反硝化(SND)工艺污水生物脱氮过程中污染物去除效果和温室气体(N2O,CH4和CO2)的释放情况.结果表明,与顺序式硝化反硝化工艺(SQND)的总氮去除率63.78%相比,SND大大地提高了总氮的去除,去除率达90.39%.同时,SND过程刺激了温室气体的释放,其温室气体释放总量为SQND的4.5倍.SND反应器N2O每周期释放量为34.28 mg,且主要集中于曝气阶段.而SQND过程N2O释放量仅为6.89mg,为SND过程的1/5.SND过程和SQND过程,每周期CO2的释放量分别为493.52,320.28mg.两反应器中CH4的释放量都很低,接近于零.     

Greenhouse gas scenarios for Austria: a comparison of different approaches to emission trends

In the present paper, national and externally organized projections of greenhouse gas emissions for Austria were compared to gain insight on the underlying scenario data assumptions. National greenhouse gas emission trends extend until 2030, an assessment of European Union (EU) countries to 2050. In addition, data for 2000–2100 was extracted from the global emission database described by the Representative Concentration Pathways (RCP). By identifying trends in these projections, it was possible to produce (a) a long-term assessment of national scenarios until 2100, (b) an assessment of the ambition level toward national climate strategies, and (c) a standardized method to compare trends across countries. By extracting RCP data, Austrian’s methane, nitrous oxide, and carbon dioxide emissions up to 2100 could be projected for all sources as well as specific sectors. With respect to the RCP scenario emission data, national projections did not seem to employ the mitigation potentials available for the most stringent RCP scenario, RCP2.6. Comparing projections that supported the EU Climate Strategy 2030 with national projections revealed similar trends. Because RCP2.6 is the only scenario consistent with a 2 °C global warming target, and it is much more ambitious than any of the national or European projections, further measures will be required if Austria is to adequately contribute to this widely accepted policy goal.     

An overview of the revised 1996 IPCC guidelines for national greenhouse gas inventory methodology for nitrous oxide from agriculture

The IPCC Guidelines for National Greenhouse Gas Inventories provide default methodologies for estimating emissions of the most important greenhouse gases at a national scale. The methodology for estimating emissions of nitrous oxide (N₂O) from agriculture was revised in 1996 by an international working group. Here we summarize this new methodology and apply it to the global data. The new method aims at assessing the full nitrogen cycle and takes into account N₂O formation in agricultural fields (direct emissions), animal waste management systems (AWMSs) as well as indirect emissions taking place at remote places after nitrogen is lost from the agricultural fields. Using the IPCC method, we estimated that global agricultural N₂O emissions almost doubled between 1960 (3.5 Tg N₂O-N) and 1994 (6.2 Tg N₂O-N). Direct emissions, animal waste management systems and indirect emissions make about equal contribution to total current emissions.     

海洋N2O氮、氧同位素组成研究进展

氧化亚氮（N₂O）不仅是重要的温室气体之一,还对臭氧层具有破坏作用。由于人为活动加剧,导致大气N₂O浓度以每年约0.25%的速率增加。海洋是大气N₂O的重要释放源。海洋溶存N₂O的氮、氧同位素组成可以反映N₂O的源与汇以及N₂O的形成机制,是海洋氮循环过程研究的一个重要示踪指标。本文简述海洋N₂O产生和消耗机制,总结不同环境中N₂O稳定氮、氧同位素组成和N₂O循环过程的同位素分馏效应,并回顾了国际上应用稳定氮、氧同位素研究海洋N₂O形成机制的研究进展,最后评述我国近海N₂O稳定氮、氧同位素研究现状并提出展望。     

Carbon emissions and management scenarios for consumer-owned utilities

An important subset of the utility sector has been scarcely explored for its ability to reduce carbon dioxide emissions: consumer-owned electric utilities significantly contribute to U.S. greenhouse gas emissions, but are often excluded from energy efficiency and renewable energy policies. They sell a quarter of the nation's electricity, yet the carbon impact of these sales is not well understood, due to their small size, unique ownership models, and high percentage of purchased power for distribution. This paper situates consumer-owned utilities in the context of emerging U.S. climate policy, quantifying for the first time the state-by-state carbon impact of electricity sales by consumer-owned utilities. We estimate that total retail sales by consumer-owned utilities account for roughly 568 million metric tons of CO₂ annually, making this sector the 7th largest CO₂ emitter globally, and examine state-level carbon intensities of the sector in light of the current policy environment and the share of COU distribution in the states. Based on efficiency and fuel mix pathways under conceivable regulations, carbon scenarios for 2030 are developed.     

华中地区畜牧业温室气体排放特征分析与预测

采用IPCC推荐的温室气体清单计算方法,从温室气体排放总量、排放强度等方面分析了华中地区畜牧业温室气体排放现状;根据不同牲畜饲养数量,采用Logisticgrowth model、Gompertzcurve model等非线性时间序列模型模拟2030年华中地区牲畜数量,并计算畜牧业温室气体排放量.结果显示,2015年华中地区温室气体排放为6289.09万t CO₂-eq,单位GDP温室气体排放量为1.13万t CO₂-eq/亿元,单位肉类产量排放强度为3.73t CO₂-eq/t;2030年华中地区畜牧业温室气体排放总量约为4990.06（温室气体排放预测1）~5932.74万tCO₂-eq（温室气体排放预测2）.应当进一步优化畜牧业饲养技术及条件来提高产业温室气体排放效率,科学合理的规划不同牲畜的饲养规模,优化牲畜饲养结构来降低畜牧业温室气体排放量.     

农田土壤N2O产生的关键微生物过程及减排措施

氧化亚氮(N2O)作为一种重要的温室气体,其全球排放总量仍然在持续上升.它不仅可以产生温室效应,还可以间接破坏臭氧层,使其在全球气候变化和生态环境变化研究中备受关注.土壤生态系统是大气中N2O的最重要排放源.本文详细论述了农田土壤中反硝化作用、硝化作用、硝化微生物的反硝化作用以及硝酸盐异化还原成铵作用等过程产生N2O的微生物学机制,并从土壤理化性质(土壤pH、氮素、有机质、土壤温度和湿度)和土壤生物等方面对农田土壤N2O排放的影响进行综述,在此基础上对农田土壤N2O的减排措施进行总结,并就今后农田土壤N2O排放的研究重点和方向进行了展望,为调控农田土壤温室气体排放、氮转化过程和提高氮素利用效率提供科学依据.     

海洋中溶存氧化亚氮研究进展

N2O是大气中重要和微量气体，对温室效应和大气臭氧层损耗有重要作用。海洋是大气N2O原重要源和汇。开展海洋中溶存N2O的研究，有助于了解海洋对大气N2O和全球变暖的贡献。本文综述了海洋中溶存N2O的研究现状，着重介绍了海洋中溶存N2O的分布特征、海气交换爱量的估算及其产生和消耗机理，并探讨了该领域研究中存在的问题。     

Leakage of nitrous oxide emissions within the Spanish agro-food system in 1961–2009

In this paper we examine the trends of nitrous oxide (N₂O) emissions of the Spanish agricultural sector related to national production and consumption in the 1961–2009 period. The comparison between production- and consumption-based emissions at the national level provides a complete overview of the actual impact resulting from the dietary choices of a given country and allows the evaluation of potential emission leakages. On average, 1.5 % of the new reactive nitrogen that enters Spain every year is emitted as N₂O. Production- and consumption-based emissions have both significantly increased in the period studied and nowadays consumption-based emissions are 45 % higher than production-based emissions. A large proportion of the net N₂O emissions associated with imported agricultural goods comes from countries that are not committers for the United Nations Framework Convention on Climate Change Kyoto Protocol Annex I. An increase in feed consumption is the main driver of the changes observed, leading to a remarkable emission leakage in the Spanish agricultural sector. The complementary approach used here is essential to achieve an effective mitigation of Spanish greenhouse gas emissions.     

污水生物脱氮过程中N2O的产生与控制研究进展

N2O是一种重要的温室气体,并且能破坏臭氧层,因而在全球变化研究中受到广泛关注.研究表明,污水生物脱氮过程是N2O的一个重要人为源.为此,对污水生物脱氮过程中N2O的产生与控制进行研究具有重要的意义.文章对污水生物脱氮过程中N2O的产生机理、影响因素和减量化策略进行了论述.N2O通常被认为是不完全硝化作用或不完全反硝化...     

秸秆还田配施生物炭对关中平原夏玉米产量和土壤N2O排放的影响

为探明秸秆还田配施生物炭对夏玉米产量和土壤氧化亚氮（N₂O）排放的影响,基于2019~2020年关中平原田间定位试验,利用静态暗箱-气相色谱法监测了土壤N₂O排放通量,综合分析夏玉米产量、土壤N₂O排放和土壤活性氮组分,明确了秸秆还田配施生物炭在培肥土壤、增产减排方面的效应.以秸秆不还田（S₀）为对照,设置秸秆还田（S）和秸秆还田配施生物炭（SB）共3个处理.结果表明,各处理N₂O排放峰值出现在秸秆还田后10 d,秸秆还田30 d后土壤N₂O排放通量处于较低水平,土壤N₂O排放通量与铵态氮（NH₄⁺-N）、无机氮、微生物量氮（MBN）和可溶性有机氮（DON）含量呈显著的正相关关系（P<0.05）.S较S₀显著增加夏玉米产量、N₂O累积排放量、单位产量N₂O累积排放量和土壤总氮（TN）含量,分别为7.4%~13%、65.8%~132.2%、54.6%~103%和27.8%~33%.虽然SB较S提高夏玉米产量（2.5%~3.3%）的趋势不显著（P>0.05）,但是SB较S显著降低N₂O累积排放量和单位产量N₂O累积排放量,分别为24.0%~27.3%和26.4%~29.2%.在土壤N₂O排放通量达到峰值时,SB较S显著降低土壤N₂O排放通量45.1%~69.6%,生物炭能够缓解秸秆还田所诱发的土壤N₂O排放,具有削峰的作用.SB较S显著增加土壤总氮9.1%~12.2%.综合作物产量、N₂O排放和土壤总氮,对夏玉米生产而言,秸秆还田配施生物炭不仅培肥地力,提高夏玉米产量,而且减少单位产量N₂O累积排放量,是可供推广的兼顾作物产量和环境友好的适宜管理措施.     

碳底物含量对厌氧条件下水稻土N2、N2O、NO、CO2和CH4排放的影响

理解底物碳氮对厌氧条件下水稻土排放氮素气体——氮气(N2)、氧化亚氮(N2O)和一氧化氮(NO)以及二氧化碳(CO2)和甲烷(CH4)的影响,有助于制定合理的温室气体减排措施,定量了解反硝化产物组成对碳底物水平的依赖性,也有助于氮转化过程模型研发中制定正确的关键过程参数选取方法或参数化方案.本研究采用粉砂壤质水稻土为研究对象,设置对照(CK)和加碳(C+)两个处理,前者的初始硝态氮和可溶性有机碳(DOC)含量分别为~50 mg·kg-1和~28 mg·kg-1,后者的分别为~50 mg·kg-1和~300 mg·kg-1.采用氦环境培养-气体及碳氮底物直接同步测定系统,研究了完全厌氧条件下碳底物水平对上述气体排放的影响.结果表明,CK处理无CH4排放,而C+处理可观测到CH4排放;C+处理的综合增温潜势显著高于CK处理(P<0.01);NO、N2O和N2排放量占这3种氮素气体排放总量的比重,在CK处理分别约为9%、35%和56%,在C+处理分别约为31%、50%和19%,处理间差异显著(P<0.01).由此表明,碳底物水平可显著改变所排放氮素气体的组成;对于旱地阶段硝态氮比较丰富的水稻土,避免在淹水前或淹水期间施用有机肥,有利于削减温室气体排放.     

北京市1990—2030年加油站汽油VOCs排放清单

加油站汽油销售量随机动车保有量同步快速增长,并已成为北京市VOCs主要来源之一. 为准确估算加油站VOCs排放,在比较国内外加油站VOCs排放因子的基础上,结合北京市加油站油气治理过程,估算北京市1990—2014年加油站VOCs排放清单,并预测2015—2030年排放清单. 结果表明:①中国、US EPA(美国国家环境保护局)和EEA(欧洲环境署)的加油站VOCs未控制排放因子分别是CARB(美国加州空气资源委员会)排放因子的1.78、1.38和0.85倍;②根据CARB排放因子和北京本地油气治理措施计算得到北京市2003年、2008年和2030年VOCs加权排放因子,分别为2 103、263和80 mg/L,2008年和2030年控制效率分别为2003年的88%和96%;③2003年加油站VOCs排放量达到峰值(5 134 t/a),在北京市实施DB 11/208—2003《加油站油气排放控制和限值》后,2008年VOCs排放量减至1 195 t/a,城六区排放量约占全市的60%;④《北京市2013—2017年清洁空气行动计划》实施后,预测2017年、2022年和2030年的VOCs排放量分别为1 252、976和531 t/a,2030年汽油消费量是1990年的8.8倍,但VOCs排放量仅为1990年的34%. 研究显示,北京市加油站油气回收工作为加油站VOCs减排做出了巨大贡献.      

Framework for improved confidence in modeled nitrous oxide estimates for biofuel regulatory standards

Biofuels vary greatly in their carbon intensity, depending on the specifics of how they are produced. Policy frameworks are needed to ensure that biofuels actually achieve intended reductions in greenhouse gas emissions. Current approaches do not account for important variables during cultivation that influence emissions. Estimating emissions based on biogeochemical models would allow accounting of farm-specific conditions, which in turn provides an incentive for producers to adopt low emissions practices. However, there are substantial uncertainties in the application of biogeochemical models. This paper proposes a policy framework that manages this uncertainty while retaining the ability of the models to account for (and hence incentivize) low emissions practices. The proposed framework is demonstrated on nitrous oxide (N₂O) emissions from the cultivation of winter barley. The framework aggregates uncertainties over time, which (1) avoids penalizing producers for uncertainty in weather, (2) allows for a high degree of confidence in the emissions reductions achieved, and (3) attenuates the uncertainty penalties borne by producers within a timescale of several years. Results indicate that with effective management, N₂O emissions from feedstock cultivation may be <?5% of the carbon intensity of gasoline, whereas the existing policy approach estimates emissions >?20% of the carbon intensity of gasoline. If these emissions reductions are monetized, the framework can provide up to $0.002 per liter credits (0.8 cents per gallon) to fuel producers, which could incentivize emissions mitigation practices by biofuel feedstock suppliers, such as avoiding fall N application on silty clay loam soils. The conservatism in the current approach fails to incentivize the adoption of biofuels, while the lack of specificity fails to incentivize site-level mitigation practices. Improved uncertainty accounting and consideration of farm-level practices will incentivize mitigation efforts at landscape to global scales.     

Effects of cracks and some key factors on emissions of nitrous oxide in paddy fields

IntroductionNitrousoxide,N2Oisofenvironmentalimportancebecauseitcontributestoglobalwarmingandthedepletionofthestratosphericozonelayer(Smith,1982).Itsatmosphericconcentrationisstillincreasingatarateof025%—031%peryear(Rodhe,1990).SignificantsourcesofN2Oarefoundinterrestrialecosystemsasaresultofnitrificationanddenitrificationprocessinsoils(Bouwman,1993).Globally,anthropogenicactivityaccountsfor64%oftotalN2Oemissions,towhichagriculturecontributes92%(Duxbury,1982).Therearesomedifferencesbetwe…