中国粮食生产的温室气体减排策略以及碳中和实现路径

作为世界上最大的农业生产国和温室气体排放国,我国承诺力争到2030年前实现碳达峰,2060年前实现碳中和。国家“双碳”目标给农业生产带来很大的减排挑战,因为农业源温室气体排放约占我国碳排放总量的14%。粮食生产是农业源非CO₂温室气体的主要排放源,归因于过量灌溉和施肥引起的稻田甲烷(CH₄)和土壤氧化亚氮(N₂O)排放。在碳达峰后,粮食生产温室气体的排放占比和减排重要性将越来越大。我国粮食生产究竟能否实现碳中和,以及如何实现碳中和仍不明确。本文综述了我国粮食生产碳排放的源汇效应和时空特征,总结了稻田CH₄和土壤N₂O减排以及农田土壤固碳的有效措施,解析了固碳减排之间的“此消彼长”效应和应对策略,明确了粮食生产实现碳中和的潜在路径,并对未来固碳减排的研究方向进行了展望。     

生物质炭对不同植被类型土壤温室气体排放影响研究进展

土壤生态系统是温室气体排放的主要来源之一，降低土壤温室气体排放对于缓解全球变暖具有重要意义。近年来，生物质炭在改良土壤性质、提高土壤碳汇和影响土壤温室气体排放方面展现出了巨大的潜力。因此，关于施加生物质炭对土壤温室气体排放影响的研究已经成为了环境科学和农业生态领域的研究热点。然而，生物质炭对土壤温室气体净排放的影响是促进还是抑制尚无统一定论。不同植被类型条件下土壤温室气体排放也存在较大差异，故而研究添加生物质炭对不同植被类型土壤温室气体排放的影响至关重要。本文综述了添加生物质炭对林地、农田及设施蔬菜土壤中CO₂、CH₄和N₂O排放的影响，探讨了生物质炭对土壤温室气体排放的作用机制。总结发现，不同植被类型土壤添加生物质炭将降低土壤N2O的排放，并且增加土地对CH4的吸收，而对CO₂排放的影响没有统一定论。结合国内外生物质炭在该领域的研究现状，未来需开展生物质炭在土壤温室气体减排领域的长期系统研究，同时应充分考虑使用生物质炭可能存在的潜在环境风险，以期为生物质炭在土壤温室气体减排中的应用提供可靠的科学依...     

常年淹水稻田甲烷产生潜力和产生途径的季节变化

甲烷的减排问题已成为各国政府和科研人员关注的焦点。稻田是温室气体甲烷的重要排放源,甲烷产生是排放的前提条件,主要有乙酸发酵和CO₂/H₂还原两条途径。常年淹水稻田甲烷排放量高,减排潜力大,但关于这类稻田甲烷产生途径的季节变化规律尚少见报道。于四川省资阳市的常年淹水稻田,采集水稻4个重要生育期(分蘖期、孕穗期、抽穗期、成熟期)的新鲜土样,通过室内厌氧培养试验观测了甲烷产生潜力,并采用稳定性碳同位素方法和氟甲烷(CH₃F,2%)抑制法,量化CO₂/H₂产甲烷的碳同位素分馏系数(α(CO₂/CH₄)),从而定量评估乙酸产甲烷途径的相对贡献率(?乙酸)。结果表明：添加CH₃F显著降低甲烷产生,甲烷产生潜力在成熟期最大,变化范围为3.22～12.71μg·g^–1·d^–1;产生CH₄的δ¹³C值(δ¹³CH_...     

不同种类秸秆还田对单季稻田CH4排放和功能微生物丰度的影响

【目的】阐明稻田土壤CH₄排放及其相关功能微生物对不同种类秸秆施用的响应机制，为稻田生态系统CH₄排放预估和减排措施的选择提供理论依据。【方法】以太湖地区典型单季稻田的原柱状土为研究对象，通过设置温室栽培试验，同步监测水稻秸秆(RS)、小麦秸秆(WS)、玉米秸秆(MS)施用模式下水稻各生长期CH₄排放通量、水稻产量、土壤微生物量碳氮含量等因子，定量化研究CH₄排放相关菌群及功能基因的群落丰度。【结果】与对照相比，RS、WS和MS处理下水稻生长期CH₄排放量分别增加289.65%、263.30%和344.43%，单位水稻产量CH₄排放量分别增加210.40%、182.35%和282.80%。水稻生育期中，土壤产CH₄菌(mcrA)群落丰度呈现上升趋势而CH₄氧化菌(pmoA)呈先上升后下降趋势。与对照相比，拔节期RS处理显著增加细菌16S rRNA和pmoA基因拷贝数，成熟期WS处理显著增加mcrA拷贝数，而MS处...     

藏北高寒草甸温室气体排放对长期增温的响应

为深入认识高寒草甸温室气体通量对长期气候变暖的响应,利用开顶式生长室（OTC,Open Top Chamber）模拟增温2a（2Y,2015-2016年）和6a（6Y,2011-2016年）对藏北高寒草甸生长季CO₂、CH₄和N₂O通量的影响。结果表明：与对照相比,生长季（6-8月）增温6Y处理和增温2Y处理分别增加和降低高寒草甸土壤CO₂排放通量,其中7月增温6Y处理CO₂排放通量显著高于增温2Y处理;增温6Y和2Y处理增加了高寒草甸CH₄吸收通量,但是处理间差异均不显著;高寒草甸N₂O排放通量表现为增温6Y＞2Y＞CK,处理间无显著差异。环境因子与温室气体排放通量的相关分析表明,CO₂、CH₄和N₂O排放通量与0～5cm土壤温度相关不显著;土壤湿度、植物地上生物量、微生物生物量碳和蔗糖酶是影响高寒草甸CO₂排放通量的关键因子;NO₃--N是影响CH₄吸收通量的关键因素;脲酶和NO₃--N是影响N₂O排放通量的主要因子。因此,增温6Y处理通过增加植物地上部生物量、蔗糖酶活性,从而提高了土壤CO₂排放通量,增温6Y和2Y处理通过增加土壤脲酶和NO₃--N含量,从而促进了土壤N₂O排放和CH₄的吸收通量。     

四川盆地丘陵区农业源甲烷排放时空变异特征及驱动因素

为探讨四川盆地丘陵区农业源CH₄排放特征,采用IPCC排放因子法估算2007—2017年农业源CH₄排放量,运用重心模型、Getis-Ord G^*_i指数检验和PLS-STIRPAT模型,探讨区域CH₄排放的时空变化特征及驱动因素。结果表明:(1)2007—2017年,盆地丘陵区农业源CH₄排放量达(32.52～35.93)万t,其中种植业、畜禽养殖业排放占比分别为44.54%～48.26%和51.75%～55.46%,总排放量呈现出随年限增加而降低的趋势,与养殖业CH₄排放密切相关。(2)2007—2017年,盆地丘陵区农业源CH₄排放重心总体向东北方向迁移; 高排放聚集区主要位于研究区东北部,呈现出扩张的趋势,低排放聚集区主要位于西南部,与高值聚集区呈现出相反的缩减趋势。(3)驱动因素中,总人口、农业从业结构和农业产值结构对农业源CH₄排放起到正向促进作用,城镇化率、单位面积施肥量、人均耕地占有量、人均GDP和农村用电量对农业源CH₄排放起控制作用。其中农业产值结构是推动研究区CH₄增长的重要因素。综上,盆地丘陵区农业源CH₄排放水平较高,时空分布差异变动较小,通过农业生产集约集中规模化可有效降低农业源CH₄的排放量。     

农村户用沼气CDM项目温室气体减排潜力

该文以湖北恩施州农村户用沼气池项目为例,利用《联合国气候变化框架公约》清洁发展机制理事会批准的方法学AMS-III. R 和AMS-I.C,分析了农村户用沼气池建设减少温室气体排放的潜力。项目位于湖北省西南部的贫困地区,涉及8个县市的33 000个农户。研究表明：户用沼气池的建设既能减少目前粪便管理方式造成的CH4排放,又能充分利用可再生能源, 减少化石燃料的使用和减少CO2温室气体排放, 预计每个农户可实现温室气体减排 1.43～2.0 t二氧化碳当量,整个项目实现年减排温室气体 58 444 t二氧化碳当量。     

农村能源建设对减排SO2和CO2贡献分析方法

农村能源建设从节约能源和开发利用可再生能源以替代常规能源两个方面对减排ＳＯ₂和ＣＯ₂作出贡献。该文以国际通用的减排量计算方法为依据,在具体分析农村能源特点的基础上,提出了农村能源建设对减排ＳＯ₂和ＣＯ₂贡献的定量分析方法、计算公式和参数,并对１９９６年农村能源建设的环境效益进行了计算。此方法可为农村能源政策分析提供有益参考。     

城市污泥堆肥与氮肥配施对稻田CH4和N2O排放及水稻重金属含量的影响

随着城市污泥量的日益增大,污泥农用备受关注。本研究通过田间原位试验,以水稻为研究对象,观测氮肥与污泥堆肥以不同比例(1︰0、0.75︰0.25、0.5︰0.5、0︰1)配合施用对稻田CH₄和N₂O排放以及植物重金属累积的影响。结果表明:随着污泥堆肥施用比例的增加,稻田CH₄排放呈线性增加(P<0.05,r=0.967)。与施全量氮肥处理相比,施全量污泥堆肥处理显著增加CH₄排放118%(P<0.05),而配施处理的CH₄排放仅增加30%～34%(P>0.05)。与CH₄相反,稻田N₂O排放随着污泥堆肥施用比例的增加而逐渐减少,与施全量氮肥处理相比,施全量污泥堆肥处理减少N₂O排放39%(P<0.05),配施处理N₂O排放减少29%～38%(P<0.05)。施全量污泥堆肥处理的温室气体排放强度(GHGI)与施全量氮肥处理相当,而配施处理的GHGI比施用全量污泥堆肥...     

稻田CH4和N2O排放对大气CO2浓度升高响应的研究进展

大气CO₂浓度升高是全球气候变化的主要驱动力,可直接或间接影响陆地生态系统碳氮循环。阐明稻田生态系统CH₄和N₂O排放对大气CO₂浓度升高的响应及其机制,是农业生产应对全球气候变化的重要组成部分。本文综述了国内外不同大气CO₂浓度升高模拟技术平台条件下稻田CH₄和N₂O排放的响应规律,进一步讨论分析了大气CO₂浓度升高影响CH₄和N₂O排放的相关机制,并展望了今后稻田CH₄和N₂O排放对大气CO₂浓度升高响应的主要研究方向,以期为应对全球气候变化提供理论依据和技术支撑。     

Study on Greenhouse Gas Emissions in Jiangsu Province

This paper has attempted to do a statistical analysis of the inventory of greenhouse gas emissions from Jiangsu province in 1990, based on the methods provided in IPCC Guidelines (1995), hereby to investigate and evaluate the present situation of emissions of GHGs such as CO₂, CH₄ from the energy sector, industries, and agriculture. The study has found the annual per capita GHG emissions as follows: CO₂, 1.97 ton/person; CH₄, 22.65 kg person^-1; N₂O, 0.11 kg person^-1. The emission levels are close to the national average, and half of the world average. Energy consumption activities, among other activities, is the main source of CO₂ emission in Jiangsu province, which accounts for 91.6% of the total emission. The emission of CH₄ can be traced mainly to the cultivation of rice, which accounts for 44.1% of the emission.

     

稻田种养结合循环农业温室气体排放的调控与机制

水稻在我国粮食作物种植中占据主导地位,在保障粮食安全、关系国计民生方面有着重要的作用。稻田是温室气体甲烷(CH_4)和氧化亚氮(N_2O)的重要排放源。因此,控制稻田温室气体排放对缓解全球温室效应具有重要作用。近年来,稻田种养结合循环农业在我国发展迅速,具有稳产增效、绿色发展的重要功效,同时显著影响了稻田温室气体排放特征以及全球增温潜势(global warming potential,GWP)。稻鸭共作、稻田养小龙虾、稻鱼共作、稻田养蟹、稻田养鳖等稻田种养结合循环农业模式,由于稻田养殖生物在稻田生态系统中添加生态位、延长食物链的增环作用,通过其持续运动、觅食活动等,不同程度地影响稻田温室气体的排放量和GWP,总体呈现出减缓温室效应的趋势。本文概述了稻田种养结合循环农业的CH_4和N_2O的排放特征及水分管理和施肥措施的影响效应,探讨了稻田种养结合循环农业的减排途径,并分析了稻田种养结合循环农业温室气体减排的研究前景,以期为我国稻田种养结合循环农业的健康发展和稻田生态系统减排增效提供参考。     

中国农村户用沼气工程建设对减排CO2、SO2的贡献——分析与预测

农村户用沼气工程是中国可再生能源建设的重点项目，可为农村居民生活提供清洁的可再生能源，该工程的建设能减轻农村环境污染，有助于部分缓解全球气候变暖的趋势。该文根据国际通用的减排量计算方法，对中国农村户用沼气替代传统生物质能和煤炭所产生的CO₂和SO₂的减排量进行了计算分析，为制定农村能源发展战略和农村环境发展规划提供参考。研究结果表明，在1996～2003年间，每年可减少CO₂排放39.76～419.39万t，减少SO₂排放2.13～6.20万t。通过对2010、2020和2050年沼气替代农村传统能源减排CO₂和SO₂量的预测，证明农村户用沼气工程的建设可以有效减少CO₂和SO₂的排放。     

Effects of land use type and incubation temperature on greenhouse gas emissions from Chinese and Canadian soils

Purpose  

Land use type is an important factor influencing greenhouse gas emissions from soils, but the mechanisms involved in affecting potential greenhouse gas (GHG) emissions in different land use systems are poorly understood. Since the northern regions of Canada and China are characterized by cool growing seasons, GHG emissions under low temperatures are important for our understanding of how soil temperature affects soil C and N turnover processes and associated greenhouse gas emissions in cool temperate regions. Therefore, we investigated the effects of temperature on the emission of N₂O, CO₂, and CH₄ from typical forest and grassland soils from China and Canada.     

Influence of increasing temperature and nitrogen input on greenhouse gas emissions from a desert steppe soil in Inner Mongolia

We investigated the effect of increasing soil temperature and nitrogen on greenhouse gas (GHG) emissions [carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O)] from a desert steppe soil in Inner Mongolia, China. Two temperature levels (heating versus no heating) and two nitrogen (N) fertilizer application levels (0 and 100?kg?N?ha^?1?year^?1) were examined in a complete randomized design with six replications. The GHG surface fluxes and their concentrations in soil (0 to 50?cm) were collected bi-weekly from June 2006 to November 2007. Carbon dioxide and N₂O emissions were not affected by heating or N treatment, but compared with other seasons, CO₂ was higher in summer [average of 29.6 versus 8.6?mg carbon (C) m^?2?h^?1 over all other seasons] and N₂O was lower in winter (average of 2.6 versus 4.0?mg?N?m^?2?h^?1 over all other seasons). Desert steppe soil is a CH₄ sink with the highest rate of consumption occurring in summer. Heating decreased CH₄ consumption only in the summer. Increasing surface soil temperature by 1.3°C or applying 100?kg?ha^?1?year^?1 N fertilizer had no effect on the overall GHG emissions. Seasonal variability in GHG emission reflected changes in temperature and soil moisture content. At an average CH₄ consumption rate of 31.65?µg?C?m^?2?h^?1, the 30.73 million ha of desert steppe soil in Inner Mongolia can consume (sequestrate) about 85?×?10^6?kg CH₄-C, an offset equivalent to 711?×?10^6?kg CO₂-C emissions annually. Thus, desert steppe soil should be considered an important CH₄ sink and its potential in reducing GHG emission and mitigating climate change warrants further investigation.     

Strong pH influence on N2O and CH4 fluxes from forested organic soils

Greenhouse gas (GHG) emissions from farmed organic soils can have a major impact on national emission budgets. This investigation was conducted to evaluate whether afforestation of such soils could mitigate this problem. Over the period 1994–1997, emissions of methane (CH₄) and nitrous oxide (N₂O) were recorded from an organic soil site in Sweden, forested with silver birch (Betula pendula Roth), using static field chambers. The site was used for grazing prior to forestation. Soil pH and soil carbon content varied greatly across the site. The soil pH ranged from 3.6 to 5.9 and soil carbon from 34 to 42%. The mean annual N₂O emission was 19.4 (± 6.7) kg N₂O‐N ha^?1 and was strongly correlated with soil pH (r = ?0.93, P < 0.01) and soil carbon content (r = 0.97, P < 0.001). The N₂O emissions showed large spatial and temporal variability with greatest emissions during the summer periods. The site was a sink for CH₄ (i.e. ?0.8 (± 0.5) kg CH₄ ha^?1 year^?1) and the flux correlated well with the C/N ratio (r = 0.93, P < 0.01), N₂O emission (r = 0.92, P < 0.01), soil pH (r = ?0.95, P < 0.01) and soil carbon (r = 0.97, P < 0.001). CH₄ flux followed a seasonal pattern, with uptake dominating during the summer, and emission during winter. This study indicates that, because of the large N₂O emissions, afforestation may not mitigate the GHG emissions from fertile peat soils with acidic pH, although it can reduce the net GHG because of greater CO₂ assimilation by the trees compared with agricultural crops.     

Water availability and abundance of microbial groups are key determinants of greenhouse gas fluxes in a dryland forest ecosystem

Forests are considered key biomes that could contribute to minimising global warming as they sequester carbon (C) and contribute to mitigate emissions of the potent greenhouse gases (GHG) including nitrous oxide (N₂O), methane (CH₄) and carbon dioxide (CO₂). Management practices are prevalent in forestry, particularly in dryland ecosystems, known to be water and nitrogen (N) limited. Irrigation and fertilisation are thus routinely applied to increase the yield of forest products. However, the contribution of forest management practices to current GHG budgets and consequently to soil net global warming potential (GWP) is still largely unaccounted for, particularly in dryland ecosystems. We quantified the long-term effect (six years) of irrigation and fertilisation and the impact of land-use change, from grassland to a Eucalyptus plantation on N₂O, CH₄ and CO₂ emissions and soil net GWP, within a dryland ecosystem. To identify biotic and abiotic drivers of GHG emissions, we explored the relationship of N₂O, CH₄ and CO₂ fluxes with soil abiotic characteristics and abundance of ammonia-oxidizers, N₂O-reducing bacteria, methanotrophs and total soil bacteria. Our results show that GHG emissions, particularly N₂O and CO₂ are constrained by water availability and both N₂O and CH₄ are constrained by N availability in the soil. We also provide evidence of functional microbial groups being key players in driving GHG emissions. Our findings illustrate that GHG emission budgets can be affected by forest management practices and provide a better mechanistic understanding for future mitigation options.     

Nitrogen addition impacts on the emissions of greenhouse gases depending on the forest type: a case study in Changbai Mountain,Northeast China

Purpose

Anthropogenic-induced greenhouse gas (GHG) emission rates derived from the soil are influenced by long-term nitrogen (N) deposition and N fertilization. However, our understanding of the interplay between increased N load and GHG emissions among soil aggregates is incomplete.

Materials and methods

Here, we conducted an incubation experiment to explore the effects of soil aggregate size and N addition on GHG emissions. The soil aggregate samples (0–10 cm) were collected from two 6-year N addition experiment sites with different vegetation types (mixed Korean pine forest vs. broad-leaved forest) in Northeast China. Carbon dioxide (CO₂), nitrous oxide (N₂O), and methane (CH₄) production were quantified from the soil samples in the laboratory using gas chromatography with 24-h intervals during the incubation (at 20 °C for 168 h with 80 % field water capacity).

Results and discussion

The results showed that the GHG emission/uptake rates were significantly higher in the micro-aggregates than in the macro-aggregates due to the higher concentration of soil bio-chemical properties (DOC, MBC, NO₃ ^?, NH₄ ⁺, SOC and TN) in smaller aggregates. For the N addition treatments, the emission/uptake rates of GHG decreased after N addition across aggregate sizes especially in mixed Korean pine forest where CO₂ emission was decreased about 30 %. Similar patterns in GHG emission/uptake rates expressed by per soil organic matter basis were observed in response to N addition treatments, indicating that N addition might decrease the decomposability of SOM in mixed Korean pine forest. The global warming potential (GWP) which was mainly contributed by CO₂ emission (>98 %) decreased in mixed Korean pine forest after N addition but no changes in broad-leaved forest.

Conclusions

These findings suggest that soil aggregate size is an important factor controlling GHG emissions through mediating the content of substrate resources in temperate forest ecosystems. The inhibitory effect of N addition on the GHG emission/uptake rates depends on the forest type.

     

Columns and Detectors Recommended in Gas Chromatography to Measure Greenhouse Emission and O2 Uptake in Soil: A Review

ABSTRACT

Gas chromatography (GC) is a technique used to analyze substances/molecules (as chemical species) with a system composed of chromatograph, column, and detector. This study has the objective of reviewing the use of GC in monitoring greenhouse gases (GHG; carbon dioxide: CO₂; methane: CH₄; nitrous oxide: N₂O) emission and O₂ (oxygen) uptake in soil, demonstrating results from experiments around the world and alternative use of sensors to monitor these gases in soil. Our study shows that the correct column and detector depend on analyzing gas and the advantages and disadvantages of the column and the detector. The columns, packed and capillary, have been more used and are considered better options to analyze GHG emission and O₂ uptake in soil science. Thermal conductivity detector (TCD), electron capture detector (ECD) and mass selective (MS) are great choice to monitor CO₂ emission; flame ionization detector (FID) equipped with methanizer allows the detection of CO₂ and CH₄ emission; and ECD detects the amount of N₂O emitted. Moreover, both, TCD and ECD, also can be used to detect O₂ uptake. GC system is complex, and to identify of GHG emission and O₂ uptake is necessary the use of column (packed or capillary) and may contain multiple detectors, i.e. three (TCD, ECD, and FID) or two detectors (FID and ECD). Field and laboratory study should be run to verify the efficacy of sensors to monitor GHG emission and O₂ uptake as an alternative of GC system.     

农业生物质能温室气体减排潜力

中国拥有丰富的农作物秸秆和畜禽粪污等农业废弃物资源。农业生物质能技术是促进农业废弃物资源有效利用的重要途径,既能够解决农业废弃物的环境污染问题、减少因焚烧或无序堆放排放温室气体,又能够替代化石能源减排CO2、提升土壤固碳能力,未来在\