农业生态经济系统生产力与多样性评价指标

对农业生态经济系统的评价指标稳定性、持续性、均衡性进行了分析,并将三者加权平均作为生产特性指数,乘以多年平均的生产率作为综合生产力,以反映系统的生产力水平及生产特性.对农业生态经济系统的结构特性提出了协调性(多样性)的量化指标,并提出了农业生态经济系统评价指标体系的建议.     

社会—经济—自然复合生态系统持续发展评价指标的理论研究

持续发展的度量或评价问题是持续发研究领域的重要问题之一。本文研究了持续发展评价指标的功能,对各种评价指标进行了比较分析,建立了持续发展的评价指标体系及综合评介指标。     

基于欧氏距离的农业可持续发展评价理论构建与实例验证

基于欧氏距离构建了农业可持续发展评价理论体系,包括农业可持续发展模型、评价函数、评价等级、目标系统、零系统与评价指标框架。选取宁夏吴忠市2000—2012年数据开展了实例验证,可持续发展指数(ASDI)范围是[0.65,0.70],呈现平缓上升趋势,呈现中持续发展状态。评价结果基本反映了农业系统情况,表明基于欧氏距离构建农业可持续发展评价方法是可行的。该方法的创新性与优势表现在:一是具有可靠的方法论;二是构建了农业可持续发展模型,引入目标系统与零系统概念,建立了农业可持续发展评价参照系,提升了评价的可控性;三是数学函数中隐含了指标权重,回避专家打分法引起的误差或错误,也回避了由于指标增减中指标权重不得不重新赋值的专家打分法缺陷;四是可持续发展评价指数采用函数模型转换,把欧氏距离转换成百分数值一方面易理解,另一方面不同系统的指数值能够进行相互比较。宁夏吴忠农业可持续发展水平偏低的主要原因是氮肥施用量高、秸秆还田率低、复合肥或专用肥比例低、保护性农作技术推广不够、土壤有机质低以及农村人均收入偏低等。     

中国农业生态系统的生产潜力和人口承载力

中国农业生态系统的生产潜力和人口承载力是全球关注的问题。本研究将农业生态系统的生产潜力定义为由生物遗传特性和4大宏观生态条件(太阳辐射、温度、水资源和土地资源)共同决定的生产力上限;以无机环境-第一性生产-第二性生产之间的结构适应性和能量-物质流平衡为主线,发展了对农业生态系统生产潜力和人口承载力的综合评价模型,它包括第一性生产潜力子模型和第二性生产潜力与人口承载力优化子模型;并应用该模型把中国农业生态系统分为603个区域单元,进行第一性生产潜力,第二性生产潜力和人口承载力的评价。     

我国农业全要素生产率的评价和指标选择研究

农业全要素生产率的评价是学术界也是政府工作评价的一大热点,但其中的指标选择和数据采集五花八门,导致结果差异较大.根据生产函数理论,基于现有官方统计数据,经过大量运算和论证,我们筛选出生产函数法最优指标集:农业总产值指数(产出)、农业物质消耗指数(资本)、受教育程度劳动力数(劳动)、农作物总播种面积+0.2×造林面积+养殖面积—灾害面积(土地).针对农业劳动力人员数抛物线趋势,建议将评价分成1952-1992年和1992年-至今两阶段进行.     

农业四大生态环境问题亟待解决

农业四大生态环境问题亟待解决农业部近期列举了农业亟待解决的四大生态环境问题：耕地数量减少、质量下降,渔业环境恶化,草原破坏严重,乡镇企业污染突出。“八五”期间,我国每年净减少耕地超过１４０万ｈｍ２,全国遭受“三废”污染的农业面积已达１．５万ｈｍ２,每...     

湖州主要森林类型土壤肥力的灰色关联度分析与评价

土壤是一个由生物及非生物组成的复杂综合体、有集散、转化、传递物质和能量的作用 ,其综合作用称为肥力[3] 。土壤肥力是从环境条件和营养条件两方面供应和协调作物生长发育的能力 ,是土壤物理、化学和生物等性质的综合反映 ,土壤结构是肥力的重要基础[11] 。土壤肥力的差异是土壤基本特性的综合表现 ,是多因素的耦合[7] 。在评价土壤肥力时 ,要考虑土壤整体剖面。目前有关土壤肥力的定义至今没有适当的内涵和外延 ,缺少量化的指标[3] 。为此 ,笔者认为 ,土壤肥力评价 ,应着眼于系统的观点 ,根据评价土壤肥力的综合指标 ,以评判该种土壤的…     

国内外心力衰竭治疗质量评价的研究现状

心力衰竭是世界主要的公共卫生问题之一,庞大的心力衰竭患者消耗着大量的医疗资源。近几十年,世界各国专家越来越关注心力衰竭的治疗质量,评价治疗质量已成为医疗体制改革的一项措施。通过总结国内外心力衰竭治疗质量评价的组织机构、评价指标、治疗质量改善项目及有关评价研究,探讨我国心力衰竭治疗质量评价与国外的差距,针对出现的问题,提出相应的建议,为改善我国心力衰竭的治疗质量提供新思路。     

意愿价值评估法应用于农业生态补偿研究进展

农业生态补偿是支持和保护农业发展的重要政策激励手段,有关补偿标准的估算及计量方法研究始终是学术界讨论的热点。意愿价值评估法(CVM)是国际社会进行非市场价值评估最广泛采用的陈述偏好方法。由于在农业生态补偿领域应用时间不长,农业产业的弱质性及农民认知水平的差距,导致国内CVM的实证研究面临许多问题和困惑。阐明CVM方法的内涵与理论基础,全面系统地梳理国内外CVM在农业补偿领域的研究进展。以激励农户采纳农业清洁生产技术补偿意愿问卷调查为例,深入探讨CVM应用于农业生态补偿政策评估中存在的假想特性偏差、研究手段偏差及调查实施偏差等。提出通过合理的技术途径和对策措施规避可能的偏差,包括:明确计量模型适用范围、开展效度与信度检验、选择两种尺度评估及处理调查过程偏差的方法等,为破解CVM应用于国内农业生态补偿政策制定中的问题提供方法和思路借鉴。研究指出存在的不足与局限性,以期未来不断完善和拓展。     

基于灰色三角白化权集对分析模型的喀斯特山区农业生态环境脆弱性评价

生态脆弱性一直是全球变化与可持续发展研究的热点问题,研究农业生态环境脆弱性问题有利于合理利用区域农业资源,提出有效的农业生态环境保护措施。针对农业生态环境脆弱性评价未考虑不同评价级别内各指标之间同、异、反关系,本研究基于灰色三角白化权集对分析(SPA)模型,从生态环境外在脆弱性方面选择人口密度、人均耕地面积、人均造林面积等11个评价指标,对喀斯特山区农业生态环境脆弱性进行评价。结果表明: 研究区农业生态环境比较脆弱,以极度、高度和中度脆弱度为主;极度、高度、中度、轻度和微度农业生态环境脆弱区比例分别为32.4%、14.1%、17.7%、23.6%和12.2%;评价结果与研究区域农业生态环境脆弱性实际状况相符。说明以灰色三角白化权SPA模型评价农业生态环境脆弱性具有可行性,可为农业生态环境脆弱性评价提供一种新的方法和思路。     

农业生态系统可持续发展趋势度的评价方法研究

在对农业生态系统时间演替过程分析的基础上,以评价指标年际变异性、评价指标的时间发展斜率变化率和评价指标的初如阈值水平为评价领域,提出了可持续发展趋势度的概念。并以德清县为例进行了案例分析,结果表明该县的可持续度为0.657,属中上水平。     

Aggregate index of social–environmental sustainability to evaluate the social–environmental quality in a watershed in the Southern Amazon

The purpose of this study was to build an aggregate index of social–environmental sustainability derived from incorporation of indicators of the quality of soil, water, and vegetation, and social organization and socioeconomic variables, in order to assess the overall social–environmental quality in a micro watershed in the Southern Amazon. From a population of 105 family production units 56 were randomly selected for evaluation of indicators of the quality of soil and water as well as for conducting interviews to evaluate the farmers’ perception of soil, water, and vegetation quality and also of socioeconomic aspects of agroecosystems. The aggregate index built from social–environmental sustainability indicators shows that the selected indicators were adequate for describing social–environmental quality and confirms the hypothesis that the studied micro-watershed in the southern edge of the Amazon is in a state of collapse, and is socially and environmentally degraded.     

Environmental, Social, and Management Drivers of Soil Nutrient Mass Balances in an Extensive Andean Cropping System

Sustainable nutrient cycling in agroecosystems combining grazing and crops has global ramifications for protecting these ecosystems and for the livelihoods they support. We sought to understand environmental, management, and social drivers of nutrient management and sustainability in Andean grazing/crop systems. We assessed the impact of farmer wealth, fields’ proximity to villages, topography, and rangeland net primary productivity (NPP) on mass balances for nitrogen (N), phosphorus (P), and potassium (K) of 43 fields. Wealthier farmers applied greater total amounts (kg) of manure nutrients. However, higher manure application rates (kg ha^?1) were associated with field proximity and NPP rather than wealth. Manure P inputs in far fields (> 500-m distant) were half those in near fields. Harvest exports increased with manure inputs (P < 0.001) so that balances varied less than either of these flows. Erosion nutrient losses in steeper far fields matched crop exports, and yields declined with increasing field slope (P < 0.001), suggesting that erosion reduces productivity. Balances for P were slightly positive in near and far fields (+2.2 kg P ha^?1 y^?1, combined mean) when calculated without erosion, but zero in near fields and negative in far fields with erosion included (?6.1 kg P ha^?1 y^?1 in far fields). Near/far differences in both inputs and erosion thus drove P limitation. Crop K exports dominated K balances, which were negative even without accounting for erosion. Modeled intensification scenarios showed that remediating far field deficits would require P addition and erosion reduction. Management nested within environmental constraints (NPP, erosion) rather than socioeconomic status drives soil nutrient sustainability in these agroecosystems. Time-lags between management and long-term degradation are a principal sustainability challenge to farming in these montane grazing/crop agroecosystems.     

棉田捕食性瓢虫控害功能的分析

在系统调查棉田捕食性飘虫种数量动态的基础上,应用生态能学的方法,分析并比较了不同插种期、套间作等农业措施对棉田捕食性飘虫控害虫功能的影响。结果表明,不同类型棉田飘虫对害虫的摄入量为26．45－70kJ.m^-2,分别占整个捕食性在天敌摄入量的28．30％－47．88％,是棉田捕食性天敌的优势种类;不同类型棉田飘虫对棉蚜的控害系数为5．07％－12．85％,并随着棉花播种期的推后和间套作呈现出下降趋势,它们在棉田生态系统害虫生态调控中发挥着重要作用。     

Pathways of assessing agroecosystem health and agroecosystem management

Intrusive agriculture development, searching for higher profitability, has inflicted permanent damage to agroecosystems. Rapid deterioration of structure and functional properties in agroecosystems has intensified the need for research on agroecosystem health and agroecosystem management. This paper describes the concept of agroecosystem health which plays an important conceptual role in evaluating agroecosystem and agricultural research. Firstly, the development of agroecosystem health research is reviewed, and agroecosystem health from various dimensions is provided. Then, the methods and general criterias of agroecosystem health assessment are outlined, and a model for evaluating agroecosystem health is established. Finally, pathways of agroecosystem management from a holistic dimension are proposed to promote agroecosystem health and provide a scientific basis for making science-based policy decisions and formulating new plans in agricultural development.     

Agroecosystem functioning on different types of soil contaminated with fluorides from aluminum production

The nitrogen cycles and functioning of agroecosystems planted with spring wheat were investigated on different types of soil contaminated with fluorides from aluminum production. The imbalance between the nitrogen fluxes directed toward the external and internal soil cycles was found to be higher in gray forest soil agroecosystems with low buffering capacity to fluoride pollution than in soddy-meadow soil. The stable functioning of agroecosystems on soddy-meadow soil (stress regime) is maintained by intense nitrogen recirculation.     

浙北平原乡镇农业生态系统结构与功能现状及其相关性研究

调查分析了浙北平原15个乡镇农业生态系统的结构和功能现状,采用聚类分析和相关分析相结合的方法,研究了系统整体结构与功能以及结构和功能两两指标间的相关性。结果表明,聚类分析能揭示系统整体结构与功能的相关性,有利于从总体上把握调整的方向;两两指标间的相关分析可以明确持定结构和功能指标间相互关系的密切程度和方向,为有针对性地进行结构调整和功能优化提供依据。     

Agroecosystems and Primate Conservation in The Tropics: A Review

Agroecosystems cover more than one quarter of the global land area (ca. 50 million km²) as highly simplified (e.g. pasturelands) or more complex systems (e.g. polycultures and agroforestry systems) with the capacity to support higher biodiversity. Increasingly more information has been published about primates in agroecosystems but a general synthesis of the diversity of agroecosystems that primates use or which primate taxa are able to persist in these anthropogenic components of the landscapes is still lacking. Because of the continued extensive transformation of primate habitat into human‐modified landscapes, it is important to explore the extent to which agroecosystems are used by primates. In this article, we reviewed published information on the use of agroecosystems by primates in habitat countries and also discuss the potential costs and benefits to human and nonhuman primates of primate use of agroecosystems. The review showed that 57 primate taxa from four regions: Mesoamerica, South America, Sub‐Saharan Africa (including Madagascar), and South East Asia, used 38 types of agroecosystems as temporary or permanent habitats. Fifty‐one percent of the taxa recorded in agroecosystems were classified as least concern in the IUCN Red List, but the rest were classified as endangered (20%), vulnerable (18%), near threatened (9%), or critically endangered (2%). The large proportion of threatened primates in agroecosystems suggests that agroecosystems may play an important role in landscape approaches to primate conservation. We conclude by discussing the value of agroecosystems for primate conservation at a broad scale and highlight priorities for future research. Am. J. Primatol. 74:696‐711, 2012. © 2012 Wiley Periodicals, Inc.     

Plant litter strengthens positive biodiversity–ecosystem functioning relationships over time

Plant biodiversity–productivity relationships become stronger over time in grasslands, forests, and agroecosystems. Plant shoot and root litter is important in mediating these positive relationships, yet the functional role of plant litter remains overlooked in long-term experiments. We propose that plant litter strengthens biodiversity–ecosystem functioning relationships over time in four ways by providing decomposing detritus that releases nitrogen (N) over time for uptake by existing and succeeding plants, enhancing overall soil fertility, changing soil community composition, and reducing the impact of residue-borne pathogens and pests. We bring new insights into how diversity–productivity relationships may change over time and suggest that the diversification of crop residue retention through increased residue diversity from plant mixtures will improve the sustainability of food production systems.     

Visions of Nature and Environmental Sustainability: Shellfish Harvesting in the Dutch Wadden Sea

The concept of sustainability has several, sometimes contrasting, meanings that may generate confusion, misunderstanding, and conflict concerning conservation and restoration practices. It is therefore desirable to clarify the concept of sustainability, thereby potentially contributing to mutual understanding, especially when social conflicts arise. This article discusses a recently published typology of three conceptions of sustainability that range from economic to ecocentric valuations of nature. We argue that the typology is incomplete because it does not include the arcadian approaches. For this reason, we introduce a “tripolar model” for conceptions of sustainability, applying it to the debate on shellfish harvesting in the Dutch Wadden Sea. We conclude that the particular visions or conceptions of sustainability held by relevant actors may have an impact on strategies for conservation.