Consequences of feasible future agricultural land‐use change on soil organic carbon stocks and greenhouse gas emissions in Great Britain

The aim of this study was to assess the consequences of feasible land‐use change in Great Britain on GHG emissions mainly through the gain or loss of soil organic carbon. We use estimates of per‐area changes in soil organic carbon (SOC) stocks and in greenhouse gas (GHG) emissions, coupled with Great Britain (GB) county‐level scenarios of land‐use change based on historical land‐use patterns or feasible futures to estimate the impact of potential land‐use change between agricultural land‐uses. We consider transitions between cropland, temporary grassland (<5 yr under grass), permanent grass (>5 yr under grass) and forest. We show that reversion to historical land‐use patterns as present in 1930 could result in GHG emission reductions of up to ca. 11 Mt CO₂‐eq./yr (relative to a 2004 baseline), because of an increased permanent grassland area. By contrast, cultivation of 20% of the current (2004) permanent grassland area for crop production could result in GHG emission increases of up to ca. 14 Mt CO₂‐eq./yr. We conclude that whilst change between agricultural land‐uses (transitions between permanent and temporary grassland and cropland) in GB is likely to be a limited option for GHG mitigation, external factors such as agricultural product commodity markets could influence future land‐use. Such agricultural land‐use change in GB could have significant impacts on Land‐use, Land‐Use Change and Forestry (LULUCF) emissions, with relatively small changes in land‐use (e.g. 5% plough out of grassland to cropland, or reversion of cropland to the grassland cover in Nitrate Vulnerable Zones of 1998) having an impact on GHG emissions of a similar order of magnitude as the current United Kingdom LULUCF sink. In terms of total UK GHG emissions, however, even the most extreme feasible land‐use change scenarios account for ca. 2% of current national GHG emissions.     

规模化奶牛场温室气体排放量评估

为了对组织层次上温室气体排放进行量化,为企业选择最有效的减排措施提供依据。该文以河北保定一规模化奶牛场为案例,利用气候变化框架公约（UNFCCC）清洁发展机制理事会批准的相关方法学、IPCC排放系数法及相关文献,在组织层次上量化了该奶牛场运行过程中的温室气体的排放与清除。案例研究结果表明,采用规模化运行管理方式及粪便管理系统时,该2 300头存栏的奶牛场年排放温室气体为11 333.2 t CO2-e或者说每头存栏奶牛年排放温室气体 4.9 t CO2-e,并提出了组织温室气体的减排建议。这对同类牛场温室气体排放量的评估具有参考意义。     

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...     

基于清单算法的湖北省土地利用碳排放效应和趋势分析

土地利用/覆被变化是仅次于化石燃料燃烧的大气CO₂浓度急剧增加的最主要的人为原因,也是影响陆地生态系统碳循环的主要因素。结合国内外低碳经济和低碳土地利用的研究背景和实践,以湖北省为研究区域,采用样地清单法计算2003—2010年间湖北省的土地利用碳排放量,分析不同土地利用方式的碳排放效应和趋势。得出的主要结论如下:（1）湖北省土地利用总碳排放量从2003年的4 921.997万t增加到2010年的9 124.897万t,呈显著上升趋势;（2）耕地和建设用地是主要的碳源。其中耕地的碳排放量成递减趋势,从2003年的265.176万t减少到2010年的262.189万t,建设用地的碳排放量呈快速上升趋势,从2003年的5 194.871万t增加到2010年的9 414.589万t;（3）林地是主要的碳汇,从2003年的536.645万t增加为550.607万t,林地的碳汇功能逐年加强。通过对不同土地利用方式的碳排放效应和趋势研究,为湖北省低碳土地利用结构优化提供了依据。     

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.     

麻疯树生物柴油发展适宜性、能量生产潜力与环境影响评估

为对西南5省麻疯树生物柴油产业的发展提供依据,该文对西南5省适宜麻疯树种植的宜能边际土地资源潜力、适宜性等级等进行研究,并对该区发展麻疯树生物柴油的能量生产、温室气体减排潜力进行分析。利用多因子综合分析法对麻疯树适宜种植的边际土地资源进行识别及适宜性评价,获得麻疯树适宜种植的边际土地资源空间分布、适宜性等级和总量;利用生命周期分析法,对不同适宜性等级的边际土地资源生产麻疯树生物柴油的生命周期净能量、温室气体减排能力进行研究;利用上述研究结果,对生命周期模型进行扩展,获得西南5省规模化种植麻疯树的总净能量生产能力、温室气体减排潜力。研究结果表明,西南5省适宜与较适宜麻疯树发展的土地资源分别为199.45和557.28万hm2;如果这些土地资源全部被利用,则该区麻疯树生物柴油净能量年最大总生产潜力为15099.194万GJ,总温室气体年减排潜力为1591.655万t。该文研究结果可为制定生物能源产业政策提供参考。     

Carbon stocks and sequestration potentials of agricultural soils in the federal state of Baden‐Württemberg,SW Germany

Soil organic carbon (SOC) inventories are important tools for studying the effects of land‐use and climate change and evaluating climate‐change policies. A detailed inventory of SOC in the agricultural soils of the federal state of Baden‐Württemberg was therefore prepared based on the highest‐resolution geo‐referenced soil, land‐use, and climate data (BÜK200 inventory). In order to estimate the quality of different approaches, C inventories of the region were also prepared based on data from the National Inventory Report (UBA, 2003) and by applying the IPCC (1997) method to the two data sets. Finally, the BÜK200 inventory was used to estimate potentials of no‐tillage agriculture (NT) and peatland restoration to contribute to C sequestration and greenhouse‐gas (GHG)‐emission mitigation since both measures are discussed in this context. Scenario assumptions were change to NT on 40% of the cropland and restoration of 50% of cultivated peatlands within 20 years. On average, grasslands contained 9.5 kg C m^–2 to 0.3 m depth as compared to only 6.0 kg C m^–2 under cropland, indicating strong land‐use effects. The SOC content depended strongly on waterlogging and elevation, thus reflecting reduced C mineralization under aquic moisture regimes and low temperatures. Comparison of the BÜK200 inventory with the approach used for UBA (2003) showed high inconsistencies due to map resolution and SOC contents, whereas the IPCC method led to fairly good agreements. Results on the simulated effects of NT and peatland restoration suggested that 5%–14% of total agricultural GHG emissions could be abated with NT whereas peat restoration appeared to have a minor mitigation potential (0.2%–2.7%) because the total area of cultivated organic soils was too small to have larger impact.     

三峡库区农业发展现状及农田CH_4和N_2O排放与减排对策

全球气候变暖的主要原因在于大气中的温室气体含量的急速增加。以低碳为特征的新发展模式成为目前减少温室气体排放、应对全球气候变暖的根本途径。农业生态系统作为最大的人工生态系统,成为温室气体的第二大来源。因此,农业活动与气候变暖关系密切。以三峡库区为例,在分析了库区农业发展面临的问题的基础上,初步估算了库区水田CH4及耕地(含水田和旱地)N2O温室气体的排放量。2008年库区水田CH4及农田N2O的排放量分别为5.5×104~6.5×104 t、8500~10000 t,提出推广免耕等保护性耕作法、改变传统种植模式,合理施肥、改进稻田生产管理技术、对稻田生产系统的时间和空间差异进行管理。     

养殖场小规模清洁发展机制（CDM）项目捆绑开发

为了探究养殖场小规模清洁发展机制（CDM）捆绑项目对减排的贡献,该文以湖北一捆绑CDM项目为案例,利用《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.D 和AMS-I.D）,评估了7个参与沼气工程项目捆绑的养殖场利用沼气工程处理猪场粪污、沼气发电替代电网电能所减少的温室气体排放量,同时分析了捆绑项目的减排成本。通过案例研究得出,7个养殖场每年可减少温室气体排放86.5%,减排CO2 37 443.7 t,采用捆绑模式后,折合每头猪的额外开发成本对比单个项目开发额外成本降低了49.71%。该研究为同类项目的开发起到一定的指导作用。     

Potential for greenhouse gas emissions from soil carbon stock following biofuel cultivation on degraded lands

Consequent to the interest in converting degraded lands for cultivation of biofuel crops, concerns have been expressed about greenhouse gas (GHG) emissions resulting from changes in soil‐carbon (C) stock following land conversions. A literature‐based study was undertaken for estimating the magnitude of emission of GHGs, particularly carbon dioxide (CO₂), following an assessment of the extent and causes of land degradation and the nature of CO₂ emission from soils. The study estimated the potential for CO₂ emission resulting from changes in soil‐carbon stock following land conversions, using oil palm (Elaeis guineensis Jacq.) as a case study. The analysis indicated that, overall, the magnitude of CO₂ emission resulting from changes in soil C stock per se following opening up of degraded land would be low compared with other potential sources of CO₂ emission. However, lack of data on critical aspects such as baseline soil C status was a limitation of the study. Soil respiration is the single best measure of GHG emission from soils. Fixation of C in additional biomass will compensate, over time, for C loss through soil respiration following a change in land use or land management, unless such changes involve conversion of existing large C stocks. Therefore, any net CO₂ emission from soils resulting from changes in soil C stock following opening up of degraded land is likely to be a short‐term phenomenon. The estimations used in the study are based on various assumptions, which need to be validated by experimental field data. Copyright © 2010 John Wiley & Sons, Ltd.     

Emission and Sink of Greenhouse Gases in Soils of Moscow

The first inventory and zoning of the emission and sink of methane and carbon dioxide in the urban structure of greenhouse gases from soils and surface technogenic formations (STFs) (Technosols) on technogenic, recrementogenic, and natural sediments have been performed with consideration for the global warming potential under conditions of different formation rate of these gases, underflooding, and sealing. From gas geochemical criteria and anthropogenic pedogenesis features, the main sources of greenhouse gases, their intensity, and mass emission were revealed. The mass fractions of emissions from the sectors of waste and land use in the inventories of greenhouse gas emissions have been determined. New sources of gas emission have been revealed in the first sector, the emissions from which add tens of percent to the literature and state reports. In the second sector, emissions exceed the available data in 70 times. Estimation criteria based on the degree of manifestation and chemical composition of soil-geochemical anomalies and barrier capacities have been proposed. The sink of greenhouse gases from the atmosphere and the internal (latent) sink of methane in soils and STFs have been determined. Ecological functions of soils and STFs have been shown, and the share of latent methane sink has been calculated. The bacterial oxidation of methane in soils and STFs exceeds its emission to the atmosphere in almost hundred times.     

银川市土地利用/覆被变化初步研究

土地利用/覆盖变化是全球变化研究的一个重要内容,并且是当前全球变化研究的前沿和热点之一。以银川市作为研究样区,利用该区近10年土地利用详查资料,对研究区的土地利用类型的数量变化、土地利用类型的相对变化率、区域土地利用程度变化和土地利用综合动态度等特征进行了定量和定性的分析,初步探讨其变化趋势,为本地及相似地区的土地调控及管理提供参考。     

黑龙江省土地利用变化的碳排放效应研究

土地利用结构的改变是影响碳排放量变化的重要因素。为探究黑龙江省土地利用变化下的碳排放效应问题,本文以土地利用变更数据、能源统计数据和土地利用/覆盖数据为基础,分析土地利用变化情况,核算碳排放/吸收量及其强度并进行区际差异分析。结果表明:黑龙江省2004—2012年用地类型中以耕地面积增长最快,其动态度为3.73%,园地大量减少;期间碳排放量逐年递增,年均增长量为6 020.85万t;建设用地是影响碳排放的最主要因素,应重点从建设用地上着手控制碳排放;黑龙江省碳排放区际差异明显,碳排放大部分集中于南部的齐齐哈尔市、大庆市、绥化市、哈尔滨市4个地级市,2010年四者碳排放量占到全省的58.17%;全省碳排放强度呈下降趋势,但年均生产总值持续增长,当前碳排放量增加不会因为碳排放强度的下降而有所减缓,倘若今后不采取有效的节能减排措施,在未来很长时间内黑龙江省净排放量将会居高不下。研究结果可为相关政策的制定提供基础依据。     

Greenhouse gas mitigation potential of agricultural land in Great Britain

The aim of this paper is to assess the greenhouse gas (GHG) mitigation potential of croplands and grasslands in Great Britain under different management practices. We consider the feasible land management options for grass and cropland using county level land‐use data with estimates of per‐area mitigation potential for individual and total GHGs, to identify the land management options with the greatest cost‐effective mitigation potential. We show that for grasslands, uncertainties still remain on the mitigation potential because of their climatic sensitivity and also their less intensive management. For croplands in Great Britain, the technical mean GHG mitigation potentials for all cropland management practices range from 17 Mt CO₂‐eq. per 20 yr to 39 Mt CO₂‐eq. per 20 yr. There are significant regional variation in all cases, with the greatest potentials in England, negligible potential in Wales and intermediate potential in Scotland, with country differences largely driven by the areas of cropland and grassland in each country. Practices such as agronomic improvement and nutrient management are the most promising options because of their impact on N₂O emissions and also their larger potential at low cost. In terms of annual emissions from agriculture, calculated mitigation potentials are small, where the technical mitigation potential of agronomy and nutrient management strategies are ca. 4.5 and 3.8%, respectively (agricultural emissions account for ca. 9% or 47.7 Mt CO₂‐eq., of total Great Britain GHG emissions, Department of Energy and Climate Change, UK). However when compared with the land use, land‐use change and forestry sector (LULUCF) emissions, nutrient management would reduce further emission reductions by approximately half of the 2005 LULUCF sink (i.e. ?1.6 Mt CO₂‐eq. per year).     

The contribution of agriculture to the state of climate: Workshop summary and recommendations

An international workshop to discuss the contribution of agriculture to climate was held in Ottawa, Canada, from 27 to 30 September 2004. It was organized under the auspices of the World Meteorological Organization (WMO), Environment Canada and Agriculture and Agri-Food Canada (AAFC). Topics included the development of agriculture, land use change, the interactions between physiological properties of vegetation, ecosystem physical properties and climate, the impact of agriculture on weather and climate, interactive mechanisms resulting from human activities, the acquisition of relevant greenhouse gas (GHG) emission data, and the promotion/adoption of management practices to reduce the impact of agriculture on the environment. It was demonstrated that important biophysical forcing with significant climate feedback exist as a result of agriculture-related land use change. It was concluded that biogeochemical forcing is usually considered but that biophysical impacts are not well characterized, and few studies have included both of these aspects. For example, human disturbances of the earth's surface that affect the energy budget might be as important climatologically as GHG emissions arising from land disturbance. It was suggested that current GHG mitigation practices should be reassessed to account for both the biogeochemical and the biogeophysical forcing, and that there are significant opportunities and risks that occur in the complex interactions between agriculture and the environment. Workshop recommendations on how to minimize the impact of agriculture on climate were developed for the scientific community, funding agencies, and the agricultural community.     

农田土壤温室气体排放机理与影响因素研究进展

根据近几年国内外相关文献，对农田土壤中二氧化碳，甲烷与氧化亚氮排放相关机理及影响因子进行了归纳，并介绍了动物废弃物施用于农田土壤所导致的温室气体排放的变化情况，同时还对一些与土壤温室气体排放影响因素有关的定量模拟方程进行了介绍。     

乌鲁木齐市土地利用结构与碳排放的关联测度研究

[目的]对乌鲁木齐市的土地利用结构与碳排放量的关系进行测度,分析一定时间范围内二者的关联度及其变化特征,从而探索土地利用碳减排途径,为乌鲁木齐市合理利用土地与生态、经济、社会效应的同步提升提供参考。[方法]基于乌鲁木齐市2001—2015年的土地利用变更数据和能源消耗数据,分别计算出碳排放总量、碳排放强度和人均碳排放量,并构建灰色关联度模型,测算乌鲁木齐市土地利用结构与碳排放总量、碳排放强度、人均碳排放量的关联系数和关联度。[结果]2001—2015年乌鲁木齐市碳排放量由8.31×10~6 t增加到2.10×10~7 t,增加了近2.6倍;土地利用结构与碳排放总量、碳排放强度和人均碳排放量三者关联度最高的分别是交通运输用地(0.730 8)、牧草地(0.765 1)和园地(0.821 5);建设用地与碳排放量关联度大。[结论]土地利用结构与碳排放的关系密切,通过科学合理地利用土地利用结构变化对碳收支的影响作用对土地利用结构进行调整,从而实现控制碳排放量是可行的。     

运用生命周期评价方法评估奶牛养殖系统温室气体排放量

准确评估奶牛养殖系统温室气体排放量是寻求有效减排措施和引导奶牛养殖业低碳发展的基础。该文应用生命周期评价方法,结合中国奶牛养殖业现状,建立了奶牛养殖系统温室气体排放量评估方法;并以此方法分析了西安郊区典型的规模化奶牛场的奶牛养殖系统温室气体排放特点和排放量。结果表明,该奶牛养殖系统主要的温室气体排放环节是奶牛肠道发酵CH4排放、饲料生产与加工、粪便贮存,其排放量分别占整个系统的48.86%、18.97%和16.39%。主要排放的温室气体是CH4、N2O,排放量分别占整个系统的55.56%和26.9%。该奶牛养殖系统每生产1kg按脂肪和蛋白质纠正的原奶(FPCT)的温室气体排放量(以CO2当量计)为1.52kg,低于全球平均的混合饲养模式原奶生产的排放量,而高于欧洲国家原奶生产的排放水平,说明减排潜力还很大。通过改善饲料、改进粪便管理模式和肥料田间管理等措施均能够减少单个环节的温室气体排放量,而不同措施对整个系统减排的贡献率还应通过生命周期评价方法进行分析。因此,建议开展不同减排措施下的生命周期评估,以获得对系统减排更有效的措施。     

国际生物质能可持续发展政策及对中国的启示

伴随着生物质能的快速发展,生物质能产业可持续性问题在全球范围内也日益引起高度重视。该文概述了国际上主要的生物质能可持续政策和标准,着重对其准则和指标进行了系统梳理,并就温室气体排放这一核心指标及不确定性加以分析。阐述了生物质能可持续准则和指标对生物质能产业政策的支持作用,并在此基础上提出了政策建议。中国应在《可再生能源法》和《生物质能发展规划》中明确提出可持续性要求,生物质能产业政策应与可持续性要求挂钩,可持续准则和指标的选取应兼具科学性和可操作性,应明确(greenhouse gas,GHG)排放核算方法学,并对最低排放要求的设置进行充分论证,同时,优先在航空生物燃料等领域构建生物质能可持续标准。     

海晏县耕地变化驱动力模型及因子分析

利用多元统计学与系统动力学原理和方法建立了海晏县耕地利用变化的驱动力模型,从县域规模水平上对海晏县耕地利用变化的驱动因子及其作用机理和过程进行了分析。结果发现,在海晏县除进入模型的总人口、年末存栏羊数是耕地利用变化的主要决定因子外,国家大政方针和政策也是该县耕地利用变化的主要驱动因子之一。最后探讨了该县土地资源可持续利用的对策和措施。