基于能值理论的农田—畜禽生产系统可持续动态

为了解我国东南丘陵山区农业生产动态及其可持续性,以福建典型山区德化县为例,构建废弃物能值比例、环境污染能值负产出等指标,运用能值理论定量分析德化县2007—2016年农田—畜禽生产系统投入产出、环境负荷及可持续性的变化。结果表明：德化县农田—畜禽生产系统能值投入以购买能值为主,占能值总投入的68%~79%,水资源能值约占21%~31%;畜禽子系统能值产出占72%以上;能值密度在2.68×10¹²~3.33×10¹² sej·m^-2之间波动上升,净能值产出率下降40%,环境负荷明显加重,2015年以来有所减轻;可持续发展指数在2007—2010年短暂上升后快速下降,由1.14降至0.42。从构建的指标来看,系统废弃物能值比例有所下降,环境污染能值产出减少约22%,综合经济效益和废弃物利用情况,近年来可持续发展状况逐渐好转。德化县目前正处于农田—畜禽系统产出结构调整期,应增加系统内部反馈能值用量,控制化肥、饲料投入,提高废弃物利用率,以实现可持续发展。     

能值分析理论在耕地可持续利用评价中的应用研究——以南京市为例

评价指标体系是耕地可持续利用评价研究的难点,正确选择评价理论与方法,构建科学、合理的评价指标体系,为正确认识耕地利用的可持续性及制定相应政策提供理论与实践依据。文章引入能值理论,在传统评价方法基础上对耕地利用中物流、能流等以太阳能值为统一衡量标准,建立新的指标体系,并对南京市1995~2004年的耕地利用进行评价。结果表明,研究时段内南京市耕地利用是向可持续方向发展的,且其可持续利用经历了两个阶段:①1995~1998年可持续性下降阶段,综合系数从1995年的1逐渐下降到1998年的0.9570;②1998~2004年可持续性上升阶段,综合系数逐年上升到2004年的1.1123。与传统评价方法相比,引入能值理论后的评价结果更能全面、客观地反映耕地利用的可持续状况。     

Efficiency and sustainability analysis of grain production in Jiangsu and Shaanxi Provinces of China

Efficiency and sustainability of grain production has now been an important issue in China. Aiming at analyzing such efficiency and sustainability in different parts of China, the grain production system of Jiangsu and Shaanxi Provinces was analyzed and compared by means of using emergy method in this study. The results showed that deterioration of emergy input structure (inorganic assistant emergy inputs increased drastically while organic ones decreased or increased little) affected the grain production system's efficiency and sustainability of both provinces, and the situation of Jiangsu Province is more serious than that of Shaanxi Province. According to the results of efficiency and sustainability analysis, this paper suggests that we should utilize environmental resources abstemiously and dramatically to reduce the assistant emergy input structure into the grain production system.     

不同资源环境梯度下吉林西部生态经济系统能值分析

利用能值方法,从东南-西北方向选取吉林西部长岭、乾安、大安、镇赉四县市进行不同资源环境梯度下生态经济系统演变的对比分析。结果表明1989-2001年研究区多项能值指标差异明显:①系统稳定性方面,降水相对较多的长岭和乾安稳定性强于镇赉和大安。能值密度及能值投入率为长岭>乾安>大安>镇赉。能值产出以及能值积累量呈增大趋势,增幅长岭>乾安>大安>镇赉;②系统产出结构变化显著,虽然种植业比例有所下降,但一直是长岭、乾安的主导产业,镇赉、大安畜牧业超过种植业成为主导产业,系统平均能值产出率为长岭(1.89)<乾安(1.96)<大安(1.99)<镇赉(2.29);③环境负载率长岭<乾安<大安<镇赉,可持续发展指数则相反;④资源环境条件尤其是降水是该区生态经济系统状态的重要影响因素。     

江苏省沿海地区耕地系统能值分析及高效持续利用评价

采用能值分析法,在对耕地资源高效持续利用内涵及评价指标界定的基础上,对江苏省沿海区域2000-2008年耕地生态经济系统的高效持续性水平进行了评价。研究结果表明:①2000-2008年江苏沿海地区耕地生态经济系统资源环境负载指数(A₁)呈上升趋势,由2000年的0.9上升至2008年的1.573。在时间序列上,系统生产要素投入能值具有较强的稳定性,而初级生产力稳定性较弱。②研究区域耕地生态经济系统具有经济效益,集约化水平不断提高。但生产要素投入结构不合理,存在集约不经济现象,且生产要素投入结构差异性呈上升趋势。2008年土地集约度(B₁)为1.85×10¹⁶sej/hm²,不可更新资源与不可更新工业辅助能值投入比例达61.13%,比2000年均有明显增长。而产出投入能效指数(B₂)则呈现下降趋势,2008年为1.036 4,比2000年降低了15.90%。③2000-2008年农民人均能值占有量保持逐年增长,2008年已达1.08×10¹⁶ sej/人,比2000年增长了92.81%,这说明农民生活水平(C₁)越来越高。但从历年环比增长率分析,存在一定的不稳定性。2000-2008年间,研究区域耕地生态经济系统能值产出密度较不稳定,总体呈现倒V字型,2005年以来研究区域耕地生态经济系统能值产出密度呈缓慢下降趋势并趋稳发展,粮食安全压力较大。     

Assessments on emergy and greenhouse gas emissions of internal combustion engine automobiles and electric automobiles in the USA

Increasing energy consumption in the transportation sector results in challenging greenhouse gas (GHG) emissions and environmental problems. This paper involved integrated assessments on GHG emissions and emergy of the life cycle for the internal combustion engine (ICE) and electric automobiles in the USA over the entire assumed fifteen-year lifetime. The hotspots of GHG emissions as well as emergy indices for the major processes of automobile life cycle within the defined system boundaries have been investigated. The potential strategies for reducing GHG emissions and emergy in the life cycle of both ICE and electric automobiles were further proposed. Based on the current results, the total GHG emissions from the life cycle of ICE automobiles are 4.48E + 07 kg CO₂-e which is 320 times higher than that of the electric automobiles. The hotspot area of the GHG emissions from ICE and electric automobiles are operation phase and manufacturing process, respectively. Interesting results were observed that comparable total emergy of the ICE automobiles and electric automobiles have been calculated which were 1.54E + 17 and 2.20E + 17 sej, respectively. Analysis on emergy index evidenced a better environmental sustainability of electric automobiles than ICE automobiles over the life cycle due to its higher ESI. To the authors’ knowledge, it is the first time to integrate the analysis of GHG emissions together with emergy in industrial area of automobile engineering. It is expected that the integration of emergy and GHG emissions analysis may provide a comprehensive perspective on eco-industrial sustainability of automobile engineering.     

Emergy evaluation of Sicilian red orange production. A comparison between organic and conventional farming

This study examines, by using emergy analysis, the production of red orange in Sicily in order to evaluate resource use, productivity, environmental impact and overall sustainability. Four different sicilian farms were studied in order to compare conventional with organic production. Several indices derived from the emergy evaluation were used: the emergy yield ratio (EYR); the environmental loading ratio (ELR); the index of sustainability (SI). Organic orange production appears to use more renewable resources and less purchased energy and materials.     

Comparison of soil N availability and leaching potential,crop yields and weeds in organic,low-input and conventional farming systems in northern California

Increasing dependence on off-farm inputs including, fertilizers, pesticides and energy for food and fiber production in the United States and elsewhere is of questionable sustainability resulting in environmental degradation and human health risks. The organic (no synthetic fertilizer or pesticide use), and low-input (reduced amount of synthetic fertilizer and pesticide use), farming systems are considered to be an alternative to conventional farming systems, to enhance agricultural sustainability and environmental quality. Soil N availability and leaching potential, crop yields and weeds are important factors related to agricultural sustainability and environmental quality, yet information on long-term farming system effects on these factors, especially in the organic and low-input farming systems is limited. Four farming systems: organic, low-input, conventional (synthetic fertilizer and pesticides applied at recommended rates) 4-year rotation (conv-4) and a conventional 2-year rotation (conv-2) were evaluated for soil mineral N, potentially mineralizable N (PMN), crop yields and weed biomass in irrigated processing tomatoes (Lycopersicon esculentum L.) and corn (Zea mays L.) from 1994 to 1998 in California’s Sacramento Valley. Soil mineral N levels during the cropping season varied by crop, farming system, and the amount and source of N fertilization. The organic and low-input systems showed 112 and 36% greater PMN pools than the conventional systems, respectively. However, N mineralization rates of the conventional systems were 100% greater than in the organic and 28% greater than in the low-input system. Average tomato fruit yield for the 5-year period (1994–1998) was 71.0 Mg ha⁻¹ and average corn grain yield was 11.6 Mg ha⁻¹ and both were not significantly different among farming systems. The organic system had a greater aboveground weed biomass at harvest compared to other systems. The lower potential risk of N leaching from lower N mineralization rates in the organic and low-input farming systems appear to improve agricultural sustainability and environmental quality while maintaining similar crop yields.     

Socio-economic factors in soil erosion and conservation

Farmer decisions with regard to production and land use are strongly influenced by socio-economic factors. In the developed world, the role of agricultural subsidies, quotas and guaranteed prices is especially important. In the past there have been many examples of economic signals which led to unfortunate and unforeseen environmental consequences (‘perverse subsidies’), including soil erosion. The problems were neglected because of an emphasis on increases in productivity and the fact that many of the costs were hidden or were external to the farm and were borne by society. In recent years ‘agri-environmental measures’ have begun to reverse the trend towards environmental degradation.     

基于能值的哈萨克斯坦可持续发展评价

运用能值方法分析2014—2018年哈萨克斯坦的资源利用和可持续发展状况。结果表明：哈萨克斯坦的总能值使用量约有89.94%依赖于本土不可更新资源,且直接出口大量粗加工原材料（如石油、矿产、金属等）。该国能值货币比率较低（9.50×10¹¹~1.22×10¹² sej/$）,单位货币所购买能值量较小;能值产出率在16.87~26.11范围内波动,从基于能值的可持续发展指数来看,2014年该指数为0.90,系统发展缺乏可持续性;2015—2018年,该指数高于1,系统发展是可持续的。此外,哈萨克斯坦环境负荷较高,主要由于对本土不可更新资源的开采及利用效率较低。对此,提出了加强可再生资源开发力度、提升资源利用效率、改善对外贸易结构等建议,以期为促进哈萨克斯坦的可持续发展提供科学依据。     

中国经济持续发展水平的能值分析

在对现行可持续发展水平度量方法进行简要评述的基础上,提出了以能值分析(EMA)为理论支撑的区域性可持续发展评价指数。作为案例研究,计算了中国1978～1998年经济系统的可持续发展指数(ESI)。中国经济系统的ESI从高到低的变化历程表明,以经济系统能值流来衡量,中国经济发展的可持续性处于下降态势,表征为前期下降剧烈,目前趋于平缓。具体表现为对资源特别是能源的过度消耗以及对环境的持续强大压力。     

中国化石能源以生物质能源替代的潜力及环境效应研究

基于1953~2007年间的统计数据,根据消耗能值相等的原则,计算了中国化石能源能值消耗量及农作物残余物可替代能值量.结果表明,建国初期,化石能源资产消耗的能值量基本可以用农作物残余物来替代;随着化石能源消耗量的与日俱增,化石能源能值消耗与农作物残余物可补偿能值之间的差距越来越大,2007年,我国农作物残余物可替代能值量仅为化石能源能值消耗量的10.35%.对生物质能替代可减少的环境价值损失估算可知:1990~2007年,由于生物质能替代可以减少因煤炭开采造成的环境治理费用773.91亿元;减少因能源消费而造成的环境污染价值损失11311.76亿元,其中由于减少SO2排放而减少的环境经济损失量占环境污染经济损失量的56.93%,减少NOx和灰分排放分别占环境污染经济损失量的33.13%和9.94%.     

基于能值分析理论的生态足迹模型及应用——以江苏省为例

在对传统生态足迹模型进行简要分析的基础上,提出基于能值分析理论的生态足迹计算模型。该改进生态足迹模型通过将生态经济系统中的各种能量流换算成对应的生物生产性土地面积,并比较计算得到的生态足迹和生态承载力,从而衡量研究区域的环境可持续发展状况。论文以江苏省为例,应用改进生态足迹模型分析其2003年生态经济系统的环境状况,得到人均生态承载力为0.2997hm₂/人,人均生态足迹为4.7228hm₂/人,生态足迹超过生态承载力,与传统生态足迹模型的计算结果相一致。但与传统生态足迹模型相比,改进生态足迹模型的计算结果能更真实地反映生态经济系统的环境状况。     

基于能值分析的小型港口可持续发展评价:以海阳港为例

运用能值分析构建小型港口发展可持续性评价模型和指标体系,以中国山东省烟台市海阳港为研究对象,利用2015年数据分析和评价了该港口生态经济系统的特征和可持续性。研究结果表明:（1）2015年海阳港生态经济系统的能值总投入为2.91×1021 sej,不可更新工业辅助能占主体地位;（2）能值自给率、集疏运稳定性、净能值产出率、单位吞吐量能值消耗、能值生态承载力和可持续发展能力指标均低于同行业或同地区平均水平,废弃物能值比率、环境负荷率、能值交换率和能值密度指标处于较高水平;（3）存在对可更新自然资源利用少、来自外部购买能值比例过高和对污水、固体废物缺乏有效的综合利用的问题;（4）有必要在节约能源、设备降耗、利用可再生能源、水资源循环利用和构筑物造价控制5个方面采取有效措施,增强港口可持续发展能力。     

A combined tool for environmental scientists and decision makers: ternary diagrams and emergy accounting

Ternary diagrams are presented as graphic tools to assist environmental accounting and environmental decision-making based on emergy analysis [Odum HT. Environmental accounting – emergy environmental decision making. John Wiley & Sons; 1996. 370 pp. [1]]. Beyond the unquestionable advantages of graphic interpretation over table analysis, the use of ternary diagrams or phase diagrams, widely used for physical chemistry evaluation of three component systems, permits the use of phase diagram properties to assess the dependence of the system upon renewable and non-renewable inputs, the environmental support for dilution and abatement of process emissions and the system efficiency. The prompt visualization of the emergy accounting data makes possible to compare processes and systems with and without ecosystem services, to evaluate improvements and to follow the system performance over time. With the aim of ternary diagrams, aspects such as the interaction between systems and the interactions between systems and the environment can be readily recognized and evaluated.     

SAFE—A hierarchical framework for assessing the sustainability of agricultural systems

Sustainable development and the definition of indicators to assess progress towards sustainability have become a high priority in scientific research and on policy agendas. In this paper, we propose a consistent and comprehensive framework of principles, criteria and indicators (PC&I) for sustainability assessment of agricultural systems, referred to as the Sustainability Assessment of Farming and the Environment (SAFE) framework. In addition we formulate consistent and objective approaches for indicator identification and selection. The framework is designed for three spatial levels: the parcel level, the farm level and a higher spatial level that can be the landscape, the region or the state. The SAFE framework is hierarchical as it is composed of principles, criteria, indicators and reference values in a structured way. Principles are related to the multiple functions of the agro-ecosystem, which go clearly beyond the production function alone. The multifunctional character of the agro-ecosystem encompasses the three pillars of sustainability: the environmental, economic and social pillars. Indicators and reference values are the end-products of the framework. They are the operational tools that are used for evaluating the sustainability of the agro-ecosystems. The proposed analytical framework is not intended to find a common solution for sustainability in agriculture as a whole, but to serve as an assessment tool for the identification, the development and the evaluation of agricultural production systems, techniques and policies.     

Emergetic ternary diagrams: five examples for application in environmental accounting for decision-making

In a recent paper, “A combined tool for environmental scientists and decision makers: ternary diagrams and emergy accounting.” [Giannetti BF, Barrella FA, Almeida CMVB. A combined tool for environmental scientists and decision makers: ternary diagrams and emergy accounting. J Clean Prod, in press] Ternary diagrams were proposed as a graphical tool to assist emergy analysis. The graphical representation of the emergy accounting data makes it possible to compare processes and systems with and without ecosystem services, to evaluate improvements and to follow the system performance over time. The graphic tool is versatile and adaptable to represent products, processes, systems, countries, and different periods of time.The use and the versatility of ternary diagrams for assisting in performing emergy analyses are illustrated by means of five examples taken from the literature, which are presented and discussed. It is shown that emergetic ternary diagram's properties assist the assessment of the system efficiency, its dependence upon renewable and non-renewable inputs and the environmental support for dilution and abatement of process emissions. With the aid of ternary diagrams, details such as the interaction between systems and between systems and the environment are recognized and evaluated. Such a tool for graphical analysis allows a transparent presentation of the results and can serve as an interface between emergy scientists and decision makers, provided the meaning of each line in the diagram is carefully explained and understood.     

Considering agro-ecosystems as ecological funds for collective design: New perspectives for environmental policy

Enhancing agro-ecosystem sustainability raises difficult challenges for environmental policy: it requires both increasing knowledge on these complex systems to design effective solutions and coordinating stakeholders with diverging interests. However, most existing environmental policies consider ecosystems’ desirable properties as given, leading ecosystem managers to favor “turnkey” solutions. How could public policy better support local collective initiatives aiming at reconciling agriculture and the environment? This paper presents an empirical case study from western France, in which a partnership between an agricultural cooperative and an ecological research center resulted in a collective design initiative. We conceptually model this initiative drawing upon recent design theories and Georgescu-Roegen’s ‘fund-flow’ model, defining ‘ecological funds’ as the starting point of a collective design process. The results highlight the importance of developing policy instruments that can better support local innovation processes through greater democratization. Adopting a design approach to sustainable agricultural landscape management could be particularly fruitful in situations where collective action is necessary but where there is no common good recognized as such, and no existing community identified.     

Addressing the dynamics of agri-food systems: an emerging agenda for social science research

The ‘modernist’ project that has come to dominate food and agricultural policy has failed to provide sustainable outcomes for many poor people in developing countries. Conventional agricultural science is not able to explain let alone address these concerns because it is based on a static equilibrium-centred view that provides little insight into the dynamic character of agri-food systems. This paper analyses how prevailing narratives of technological change and economic growth have come to dominate key food and agriculture policy debates. It seeks to counter these orthodox notions by emphasising that agri-food systems are embedded in complex ecological, economic and social processes, and showing how their interactions are dynamic and vulnerable to short-term shocks and long-term stresses like climate change. The paper makes the case for a deeper understanding of diverse ‘rural worlds’ and their potential pathways to sustainability through agriculture. Moreover, it argues for a normative focus on poverty reduction and concern for the distributional consequences of dynamic changes in agri-food systems, rather than aggregates and averages. Finally, it sets out an interdisciplinary research agenda on agri-food systems that focuses on dynamic system interactions in complex, risk-prone environments and explores how pathways can become more resilient and robust in an era of growing risk and uncertainty.     

农业经营规模化发展对环境效率的影响——基于地块层面的实证分析

为探析农业规模化经营与农业环境可持续性之间的关系,对农业经营规模对农业环境效率的影响进行理论分析,并在此基础上构建了物料平衡原则下农业环境效率测算模型和农业环境效率影响模型.基于2004~2016年浙江省农户水稻种植地块层面的面板数据,实证检验了土地面积、劳动投入、资本投入和农业产出等农业经营规模指标对农业环境效率的影响.结果显示,农业规模化发展将因投入和产出的扩张以多种方式影响其环境效率,其中土地面积规模与农业环境效率之间呈倒U型关系,劳动投入和资本投入对农业生产环境效率均有负向的影响,而农业产出规模的增加将促进农业环境效率的提升.