社会经济系统氮素流动及其环境负荷——以长江中下游城市群为例

以长江中下游城市群为例,运用物质流分析方法,定量识别了区域社会经济系统的氮素流动过程及特征,评估和比较了农业生产、工业生产以及生活消费过程造成的环境氮负荷。研究结果表明,2011年长江中下游城市群社会经济系统的氮素输入总量为993.56×104t,氮素输出总量为732.84×104t,工业固氮、饲料进口和能源消费是新增氮素的主要来源,环境排放是最大的氮输出方式。2011年整个系统向周围环境排放的氮总量为760.99×104t,其中向大气、耕地和水体排放的比例分别占47.24%、19.42%和18.60%,6个子系统的环境氮排放贡献排序依次为农业种植(43.83%)工业生产(16.59%)城市生活(16.14%)畜禽养殖(13.96%)水产养殖(6.08%)农村生活(3.40%)。目前,农田施肥过度浪费、畜禽养殖与农业种植脱节且废物处理率低、工业行业高耗能高污染以及机动车大量排放是造成长江中下游城市群环境氮负荷的主要原因。今后,在快速工业化、城镇化进程以及大量农业活动中,农业种植子系统重点应减少肥料使用量和优化用肥结构,尤其是大幅减少化肥投入;畜禽养殖子系统应适当增加规模化养殖废物还田比例,提高废物资源化和综合利用水平,统筹安排污染治理设施建设;工业生产子系统应积极推进企业清洁生产,调整和优化工业能源结构,严格执行高耗能高污染行业环境准入;生活消费子系统应在加强生活污染治理、废物资源化利用的同时,严格控制机动车尾气排放标准。     

区域（城市）环境——经济系统能流分析研究

物质和能量流动是环境-经济系统得以正常运行的必要条件,该系统是一个将原料、能源转化为产品和废弃物的代谢过程.相对物质流动,能量流动呈单向流动,并且在流动过程中利用效率较低,从而导致这一过程对自然环境产生负面影响.参考物质流分析方法,提出区域环境-经济系统能流分析的研究框架,对分析的主要能源类型、系统边界、数据的获取途径与处理(如以能值分析中的太阳能值作为统一的分析单位)进行了说明;在以往能流分析、物质流分析和能值分析研究的基础上,提出区域环境-经济系统能流分析的分析指标.通过对区域{城市)环境-经济系统的能量流进行分析,其结果可以为区域能流的优化管理、优化能源使用结构、污染物总量控制、节能减排等能源政策的制定提供导向.     

环境约束下大都市城郊土地利用结构评价——基于信息熵和非期望产出模型分析

土地利用过程中会产生期望和非期望产出,针对以往土地利用结构评价中忽略环境产生的非期望产出而影响土地利用结构效率真实性问题,以大都市城郊的上海青浦区为例,宏观上,运用信息熵模型对该区2005~2014年土地利用结构有序性进行评价;微观上,运用非期望产出模型测算青浦区研究期间土地利用结构效率,为寻求区域土地利用结构效率损失的原因及改善途径提供参考。结果表明:(1)2005~2014年青浦区土地利用结构信息熵值时序上呈现"M"形变化趋势,空间上由中部向东西两翼递减;(2)2005~2014年青浦区土地利用结构效率变化趋势在时间序列上呈现"W"形变化趋势,空间上由中部的中心城区向东西两翼递减格局;(3)将环境的负产出纳入非期望产出模型进行土地利用结构效率评价,能更加准确的反映土地利用结构效率的真实性;(4)影响青浦区土地利用结构效率水平变化的主要因素为纯技术效率的变化,资源过度消耗和环境污染物排放过量是制约青浦区土地利用结构效率提升的主要原因。针对土地利用结构效率损失的原因及区域差异提出效率提升途径。研究结果可为青浦区土地利用结构优化和可持续发展提供科学借鉴。     

工业固废生态链的构建对区域物质流的影响

2008年,我国工业固废产生量达1.9亿t,比上年增长8.31%。大量工业固废排放不但占用土地、污染环境,还是对资源的一种浪费。我国工业固废以尾矿、冶炼渣、化工废物、原液及母液为主,其中还蕴藏着可用资源。近年来,工业固废的综合利用力度逐渐加大,综合利用率达到64.33%,但与国外相比还存在一定差距。本文在分析我国工业固废综合利用现状的基础上,提出工业固废链构建原则,并采取物质流分析方法,通过定量研究工业固废生态链(简称固废链)建立前后区域经济系统物质流总量及效率的变化,揭示了工业产业与区域经济和环境的相互影响机制。并以北京钢铁工业为例,在综合分析北京钢铁工业固废利用现状的基础上,通过构建北京钢铁工业固废链,定量地给出了工业固废链构建对于区域物质流的影响。结果表明:北京地区通过构建钢铁固废链,可减少区域物质总需求3 581.21万t,减少区域物质输出616.65万t,并提高区域物质生产力3.56个百分点,有利于促进区域循环经济的发展。     

基于多区域投入产出模型的国际贸易隐含水体氮排放转移研究

经济全球化进程的加快是贸易隐含污染物排放转移的主要驱动因素,近年来氮足迹与全球氮循环问题日益引发关注,水体氮是氮的主要存在形式,主要来自于种植业、畜禽养殖业、氮肥生产以及城市生活污水排放。本研究利用全球污染排放数据库,基于2015年的全球投入产出模型,从污染转移总量以及贸易流污染排放强度两方面计算了国际贸易对全球水体中的氮排放格局的影响。主要结论:(1)水体氮排放量的转移方向与大小与区域距离的远近、农业资源的丰富程度以及经济发达程度有关。水体氮排放转移量较大的贸易流大部分为经济较发达的区域向经济次发达区域的污染转移,一些农业资源禀赋程度相似、区域距离较远的区域污染转移量一般较小。一个国家向经济发展程度比自己低的区域出口的产品流隐含的污染强度低,向比自己经济发展程度高的区域出口的产品污染强度高。建议通过农机具援助、技术培训等方式,加快对非洲、亚洲等区域的农业技术转移和扩散,帮助农业生产欠发达地区提高农业生产力和管理水平,降低欠发达地区向发达地区出口的贸易流中的污染强度。(2)2015年,中国贸易隐含的水体氮污染净进口量为16万t,占到全球水体氮进口的2. 72%,谷物进口大幅增加是产生水体氮净进口的重要原因。大幅增加的进口以及过高的粮食库存不仅给世界带来资源环境压力,也进一步加剧了本国的资源环境压力,因此不仅应从产量上关注粮食安全,还要从生态安全的角度调整粮食供给结构、种植结构和进出口结构,最大限度的降低因农业生产带来的资源环境压力。     

农林复合生态系统氮素平衡及其评价

农业生态系统中养分的平衡状况及其合理性评价，是探讨农业生产和环境变化的前提和基础。选择三峡库区上游川中丘陵区一典型农林复合生态系统，依据系统养分循环概念模型，进行了农田和林地定位监测、耕地和盆钵模拟试验以及参与式农户调查等，研究系统的氮素各收入支出参数，计算系统的氮素平衡并对平衡合理性进行评价。结果表明，本复合生态系统旱地和整个农田子系统氮素略有盈余，盈亏量分别为56.1 kg/hm2·a和42 kg/hm\2·a，实际盈亏率为10.4%和8.2%；而水稻田和复合系统有少量亏缺，盈亏量分别为-13.21 kg/hm2·a和-37.5 kg/hm2·a，实际盈亏率分别为为-3.2%和-7.8%；林地亏缺较大，盈亏量为-165.9 kg/hm2·a，实际盈亏率为-39.2%。模型计算的允许盈亏率（旱地23.4%，水稻田-37.2%）评价表明，旱地和水稻田目前的氮素平衡基本上是合理的。与1960s系统氮平衡比较，可以看到林地在减少水土流失、促进养分的合理循环方面发挥了重要作用，应受到充分的重视。     

基于循环经济的流程工业企业物质流建模与仿真

流程工业属于资源消耗高、污染排放量大的行业。目前,发展循环经济,探索降低资源消耗与环境污染的途径,做好企业内部物质循环,是流程工业企业的迫切需求。本文将物质流分析方法与Petri网方法结合起来,给出一种从物质流分析模型到Petri网模型逐步形式化的建模方法,基于该方法实现某盐湖化工企业生产系统的物质流建模,并利用Matlab中Stateflow工具实现对模型的仿真运行,达到对企业生产过程的物质流进行量化分析和动态模拟的目的。研究结果表明,采用物质流分析与混杂Petri网相结合的逐步形式化建模方法,使所建模型既可以清晰直观地描述出错综复杂的物质流动过程,量化企业物质利用情况,又可以体现出物质流动过程的连续性受生产过程离散操作的影响,为企业进行循环经济的量化评估与决策制定提供了方法及依据,有助于实现整个过程物耗与污染的降低,减少故障发生率,促进流程工业企业获得经济和社会效益。本文结合案例分析,进一步突出了建模方法的应用价值。研究认为,对于流程工业企业,要提高物质利用效率、减少环境污染排放,关键在于对物质的流动情况、消耗强度以及污染排放结构的把握,这样才能加强本企业范围内物质循环利用,进而可以推动与企业乃至社会之间的物质循环。最后,针对循环经济系统的特点,文章提出将能量流与信息流考虑在内,构建物质流、能量流与信息流的耦合Petri网模型,并进一步改进仿真方法,增加仿真过程的可控性等建议。     

平原圩区城镇雨洪淹没模拟与调控策略——以昆山市淀山湖镇为例

模拟与评价雨洪淹没特征是科学评估暴雨洪涝灾害风险与优化雨洪调控措施的基础。以长三角典型平原圩区城镇淀山湖镇的8个圩区为例,基于地形、气象、雨水管网等数据,通过构建多重现期的降雨情景,采用一维SWMM模型模拟了雨水管网的溢流特征,耦合二维CADDIES模型识别了管网溢流在地表形成的雨洪淹没区域,定量评估了雨洪淹没特征的主要影响因素,并阐明提升泵站排涝能力与增加水面面积2种雨洪调控情景的优化效果。结果表明：(1)溢流点数量受圩区地表属性和降雨特征的共同影响,淹没面积与降雨特征显著相关,降雨重现期大于0.63 a且逐渐增大时,淹没面积亦随之显著增加;(2)在强降雨情景下,淀山湖镇雨水管网负荷较高且不能有效应对超过50 a的强降雨事件;(3)提升泵站排水能力能有效减少淹没面积,但未能减少溢流河道以及雨水管网溢流点数量;(4)增加水面面积能显著提升圩区雨洪调控能力,当新兴圩、永胜圩和红旗圩水面率分别达到6.03%、10.87%和8.83%时,可有效抵御100 a降雨事件所导致的河道溢流状况。研究结果可为长三角地区平原圩区的雨洪灾害风险评估与雨洪调控措施优化提供决策参考。     

耦合PLUS-InVEST-Geodector模型的三峡库区碳储量时空变化及其定量归因

探明区域长时期陆地生态系统碳储量时空变化及其影响因素对于碳中和目标实现具有重要的理论与现实意义。研究耦合PLUS-InVEST-Geodector模型,探究三峡库区1990～2035年不同情景下碳储量时空变化规律,并从土地利用变化以及自然-社会经济复合关系角度定量揭示其影响碳储量变化归因。结果表明：(1)1990～2020年三峡库区碳储量表现为“减少-增加-减少”的波动性,整体减少6.66 Tg,减幅为1.25%,其中耕地大面积转移至建设用地是导致碳储量减少的主要原因;(2)1990～2035年三峡库区碳储量空间分布与土地利用变化具有高度一致性,其空间异质性较为显著,总体呈现出“东高西低,南低北高且库首>库腹>库尾”的分布特征;(3)2035年自然发展情景和生态保护情景碳储量较2020年分别减少7.53和0.37 Tg,生态保护情景较自然发展情景能显著降低库区碳储量损失;(4)影响碳储量时空变化因素较为显著,其中土地利用变化是其主导因子,其次则为温度、人口密度、高程和土壤类型,且各因子交互作用均对碳储量变化解释力增强。研究可为库区碳库管理以及碳储功能的可持续发展提供科学参考...     

基于三生空间功能的上海市农村居民点特征演变及优化研究

农村居民点的布局与利用变化和区域社会经济状况密切相关.以经济发达地区上海市为例,从"生产-生活-生态"空间的功能角度出发,运用GIS空间分析、熵权法、景观生态学等方法对农村居民点的特征演变进行研究.结果表明:(1)根据三生空间功能评价结果,可以将上海市划分为非农生产生活区、三生协调区、生产主导区和农业生产生态区等4个具有独特禀赋特征的功能区域;(2)空间功能是农村居民点演变的基础,在其他社会经济因素的作用下,形成2005～2018年不同区域差异化的演变趋势;(3)截至2018年底,3个区域农村居民点规模:农业生态区＞生产主导区＞三生协调区;形状规整程度:生产主导区＞三生协调区＞农业生态区;分布集聚程度:农业生态区＞三生协调区＞生产主导区.根据上述结果,结合《上海市城市总体规划(2017～2035年)》提出了各功能区农村居民点布局优化策略.研究结果有助于直观地揭示土地利用布局与区域社会、经济、生态等状况的动态关系,促进构建可持续发展的新型城乡体系.     

Attitude of a group of Belgian stakeholders towards proposed agricultural countermeasures after a radioactive contamination: synthesis of the discussions within the Belgian EC-FARMING group

In the case of radioactive contamination of the environment with an impact on the food chain, the remediation strategy will not only be based on scientific knowledge and technical experience, but will also be dictated by peculiarities of the country. These characteristics include the agro-industrial structure, the local and international economical contexts and the political configuration including the distribution of responsibilities and competencies. This paper identifies and illustrates the most relevant characteristics of the Belgian agricultural system and political environment; it also describes the past experience with food chain contamination, which is expected to influence the attitude of Belgian stakeholders, who would be involved in the setting up of countermeasure strategies for maintaining agricultural production and food safety. The picture drawn explains why several countermeasures aiming to reduce the contamination in food products, although scientifically sound and technically feasible, are hardly acceptable or even not acceptable at all, to the stakeholders.     

From farm to gun and no way back: Habsburg gunpowder production in the eighteenth century and its impact on agriculture and soil fertility

Understanding the dynamics of society’s physical exchange processes with the environment (society’s metabolism) is a major theme of long-term socioecological research. In this paper, we adapt the concept of socioecological metabolism to analyze the competition between gunpowder production and agriculture for nitrogen (N) in the pre-industrial agro-ecosystem of Pamhagen in the late eighteenth century. Saltpeter (KNO₃)—the main ingredient of gunpowder—was chemically refined from agricultural waste products, in particular manure and wood ash, which were vital for the maintenance of soil fertility. In this paper, we reconstruct nitrogen flows in the agro-ecosystem of Pamhagen and establish a nutrient balance, which allows assessing the impact of saltpeter production on agricultural soil fertility management. We find that nitrate extracted by saltpeter production in our case study was equivalent to 23 % of the total available nitrogen in manure in 1778 and 12 % in 1780. The growing demand for gunpowder and thus the artisanal production of saltpeter became influential drivers in the management of societal nitrogen flows on the local level, competing over key resources for sustaining soil fertility and leaving a substantial imprint on the nutrient budget of agricultural soils as less nitrogen was available for plant uptake.     

蔬菜出口产地农户对食品安全规制的认知及其农药决策行为研究

食品安全与农药残留一直是备受关注的焦点问题。基于此,本文应用山东省蔬菜出口产地安丘市392个农户的调查数据,对农户食品安全规制的认知及其农药使用行为的影响因素进行了分析。研究结果表明,农户的学历层次、农产品国内销售和出口日本的比例、农户对国内外农产品市场的评价及是否接受农药残留检测显著影响其对食品安全规制的认知;而农户的平均生产支出、是否接受农药残留检测、检测标准的严格程度及是否作生产记录影响其农药使用行为。此外,本文发现该制度的实施导致一些农户产生逆向选择,且农户的农药使用因种植结构而不同。针对当前农业生产的特点和食品安全现状,为了促进当地农业生产方式的转变和保护生态环境,政府应加强对农业主体的培训和技术指导,引导当地农户加强与产业组织的联系,有效开展农药残留检测、优化种植结构,提高农产品的质量和国际竞争力。     

MRIO model-based study on water nitrogen pollution transfer embodied in international trade

This study uses the global pollutant emission databases and global input–output model in 2015 to calculate the impact of international trade on global water nitrogen emission patterns, based on considering the total amount of pollutant transfer and pollutant emission intensity of trade flows The main conclusions are as follows: (1) There are always a large amount of water nitrogen emissions transferring from developed economies to developing economies embodied in their bilateral trade activities. Small amount of transfers are of some areas with similar endowments of agricultural resources or long distances. (2) In 2015, the net import of water nitrogen pollution embodied in China’s trade was 160,000 tons, accounting for 2.72% of the global water nitrogen imports. The sharp increases in cereal imports, together with high food storage as well as high pollution intensity embedded in trade are the main reason. It is recommended that through applying alleviations such as agricultural machinery assistance and technical training to accelerate the transfer and spread of agricultural technology in Africa, Asia, and other regions, thus helping increase agricultural production productivity in underdeveloped areas and reducing the pollution intensity embodied in trade flows from underdeveloped areas to developed areas.     

How changes in diet and trade patterns have shaped the N cycle at the national scale: Spain (1961–2009)

During the last five decades (1961–2009), Spain has experienced a considerable expansion in the nutrient cycle of its agricultural sector and, in particular, a threefold increase in anthropogenic reactive nitrogen inputs, from 536 Gg N year^?1 in 1961–1965 to 1673 Gg N year^?1 in 2005–2009. Import of feed (soybean, cereals, and cakes) from America and Europe to supply a growing livestock population constitutes the largest share of this increase, along with intensification of synthetic fertilizer use. While in the early 1960s, Spain was nearly self-sufficient in terms of food and feed supply, the net import of agricultural products presently equals domestic crop production, when expressed in terms of nitrogen content (ca. 650 Gg N year^?1). The most important driver of this shift appears to be the rapid change in domestic consumption patterns, which evolved from a typical Mediterranean diet to an animal-protein-rich diet similar to the North European and American diets. Besides livestock production mostly for national consumption, the Spanish agricultural system has specialized in vegetal products with low N content such as olive oil, wine, vegetables, and citrus fruit, which are for the most part exported. The nitrogen load exported outside the Spanish borders by rivers is very low (6.5 % of the total net N input). As a result of the high import and low export of reactive nitrogen, the Spanish mainland is suffering from considerable pollution by local emissions of reactive nitrogen forms to air and water.     

农业生产对土壤盐渍化影响的经济分析

研究农业生产活动对土壤盐渍化的负面影响，有利于合理安排农业公共投资，促进生产与环境协调发展。在介绍我国土壤盐渍化概况的基础上，利用相关文献分析影响土壤盐渍化的不同因素，同时利用省级Panel数据和计量模型进一步探索农业生产活动对土壤盐渍化的影响。结果表明，灌溉程度、单位钾肥投入会对土壤盐渍化产生显著影响。单位耕地上灌溉面积越多，耕地发生盐渍化的概率也越高；同时单位面积上钾肥使用量越高，耕地发生盐渍化的概率也越高。此外，还在统计意义上发现排灌对抑制土壤盐渍化具有明显作用。因此，针对农业生产活动对农业生态环境可能造成的负面影响，进一步提出应该在增加农业公共投资的背景下，加强农业基础设施的建设，引导农户采用合理的农业生产方式，以协调我国农业生产与农业生态环境的和谐发展。     

Protein futures for Western Europe: potential land use and climate impacts in 2050

Multiple production and demand side measures are needed to improve food system sustainability. This study quantified the theoretical minimum agricultural land requirements to supply Western Europe with food in 2050 from its own land base, together with GHG emissions arising. Assuming that crop yield gaps in agriculture are closed, livestock production efficiencies increased and waste at all stages reduced, a range of food consumption scenarios were modelled each based on different ‘protein futures’. The scenarios were as follows: intensive and efficient livestock production using today’s species mix; intensive efficient poultry–dairy production; intensive efficient aquaculture–dairy; artificial meat and dairy; livestock on ‘ecological leftovers’ (livestock reared only on land unsuited to cropping, agricultural residues and food waste, with consumption capped at that level of availability); and a ‘plant-based eating’ scenario. For each scenario, ‘projected diet’ and ‘healthy diet’ variants were modelled. Finally, we quantified the theoretical maximum carbon sequestration potential from afforestation of spared agricultural land. Results indicate that land use could be cut by 14–86 % and GHG emissions reduced by up to approximately 90 %. The yearly carbon storage potential arising from spared agricultural land ranged from 90 to 700 Mt CO₂ in 2050. The artificial meat and plant-based scenarios achieved the greatest land use and GHG reductions and the greatest carbon sequestration potential. The ‘ecological leftover’ scenario required the least cropland as compared with the other meat-containing scenarios, but all available pasture was used, and GHG emissions were higher if meat consumption was not capped at healthy levels.     

The use of green criteria in the public procurement of food products and catering services: a review of EU schemes

Green Public Procurement (GPP) is currently being used to influence the market to shift to a supply of goods and services to the public sector that have a reduced environmental impact. The food service sector plays a major role in the purchases made by the public sector and due to that relevance deserves attention. The GPP schemes reviewed were those that provide details of the specific environmental criteria used (or recommended) for public tendering of food products and catering services provision. The set of GPP schemes apply to distinct geographical zones within the EU, including national level (e.g. Italy), regional level (e.g. Barcelona) and also local level, as in the case of cities (e.g. Copenhagen) or schools (e.g. a school in Pisa, Italy). The criteria set covers services provision to schools, health and social care, higher education, government office canteens, sports and leisure arenas, prisons and defence services (e.g. army). European and worldwide GPP criteria were not covered by the review made. This exploratory study comprehends a total of 23 GPP schemes. This sample includes eight national schemes, three regional schemes and ten local schemes. The review focused on the scope, for the sector of applicability (e.g. education, healthcare) of the GPP set of criteria and for the type of food products covered. Moreover, this paper analyses the type of GPP criteria in use and how the environmental criteria cover the distinct life cycle stages of the whole food supply chain. Findings from the analysis show that for the majority of schemes the scope of criteria is simultaneously the provision of food products and catering services. Moreover, cities, municipalities and counties are the main public authorities reporting procurement activities for the education sector while national GPP activities are applicable for multiple sectors of activity. The main food products covered by the criteria are fruits and vegetables, dairy products, fish and seafood and meat. Finally, the findings show that the set of criteria from the schemes cover widely the life cycle stages of the food supply chain. The results allowed for a first identification of current practices in the use of GPP criteria within public purchasing of food products and catering services in Europe by national, regional or local governments.     

中国种植业产品贸易自由化对环境影响的计量经济分析

入世后．中国将根据WTO的要求对农业贸易相关政策进行调整和改革，这将改变国内农业生产，进而影响到农村生态环境。在此背景下．本文首先界定了种檀业产品贸易自由化的涵义．并对其环境影响途径进行分析．然后利用计量经济方法着重分析了贸易自由化对国内种植业生产中化肥、农药使用的影响。研究结果表明，在种植业产品的贸易自由化中，进口渗透作用对缓解国内化肥、农药污染影响显着．而出口导向作用影响不明显。文章最后给出了减缓农产品贸易自由化的不利影响，发挥其有利影响的政策建议。     

Heavy metals in agricultural soils of the European Union with implications for food safety

Soil plays a central role in food safety as it determines the possible composition of food and feed at the root of the food chain. However, the quality of soil resources as defined by their potential impact on human health by propagation of harmful elements through the food chain has been poorly studied in Europe due to the lack of data of adequate detail and reliability. The European Union's first harmonized topsoil sampling and coherent analytical procedure produced trace element measurements from approximately 22,000 locations. This unique collection of information enables a reliable overview of the concentration of heavy metals, also referred to as metal(loid)s including As, Cd, Cr, Cu, Hg, Pb, Zn, Sb. Co, and Ni. In this article we propose that in some cases (e.g. Hg and Cd) the high concentrations of soil heavy metal attributed to human activity can be detected at a regional level. While the immense majority of European agricultural land can be considered adequately safe for food production, an estimated 6.24% or 137,000 km² needs local assessment and eventual remediation action.