深圳市滨海湿地两个观光农业系统的能值整合研究

应用能值研究方法对深圳市海上田园旅游区的芦花湖和农家小院两个观光农业系统进行了生态经济分析.从系统和子系统两个层面,进行了能值产出、环境负载、可持续发展能力的评价与比较;与珠三角另一个观光农业系统(百万葵园)、两个基塘农业系统(菜-鱼、菜-猪-鱼)和一个巴西基塘系统(谷-猪-鱼)进行了横向比较.从货币收益的角度看,农家小院系统的费用使用效率、商品生产获利能力要优于芦花湖系统.但能值整合分析却显示出不一样的结果:两系统内旅游业子系统的能值交换率较高,而二者的农牧业子系统及农家小院系统的水产业子系统的能值交换率均较低,其生产效率仍有待提高.芦花湖系统的环境负载率为7.31,能值可持续发展指标为0.255,分别是农家小院的0.25倍和2.26倍,因而更具长远发展优势.与传统农业相比,观光农业的能值交换率和环境负载率整体偏高,表明其在经济效益创造上优于传统农业,但在自然资源利用和环境压力,以及可持续发展能力等方面与传统农业尚存在差距,在今后的发展中需借鉴传统农业的经验并加以改善,防止观光农业发展中绿色产业褐色化现象的发生.     

Co-creating an alternative: the moral economy of participating in farmers’ markets

Growing dissatisfaction with the globalised food system, articulated on the behalf of both producers and consumers, has caused a variety of public debates surrounding the ethics of food production and consumption to become increasingly visible in society over the last two decades. Simultaneously, farmers’ markets (FMs) and other forms of direct marketing have experienced a noteworthy increase in participants, indicating an emerging demand for an alternative to conventional food networks, alternatives that are often perceived as providing a more just and moral relationship to food production and consumption. This study examines consumer and producer motivations for participation in FMs and opinions towards conventional and alternative agriculture in order to elucidate what (if any) values and morals are shared among producers and consumers. This study draws upon the theoretical framework of moral economy to understand whether these shared values suggest FM participants are working to co-create an alternative economy based on “moral” principles such as fairness, justice, and reciprocity. This mixed-methods study consists of consumer surveys (N?=?377) and semi-structured interviews with producers (N?=?17) from five FMs in the state of Delaware. The results suggest that producer and consumer motivations to participate in FMs, particularly a shared emphasis on social value, are indicative of a sense of moral economy. However, this moral economy is complicated by tension towards consumers and the alternative food movement more generally expressed on behalf of producers.     

Policy Utopias for Nutrient Credit Trading Programs with Nonpoint Sources

A promising program to address water contamination from nutrients is water quality trading (WQT), whereby entities with high abatement costs purchase credits from entities with lower abatement costs. The concept has found some success with point source water pollution, but very few trades have occurred in over 50 programs in the United States (U.S.) that have focused on nonpoint sources (NPSs). To understand why success has been slow, we identified three environments needed for programs to succeed: physical, economic, and institutional. We estimate that only 5% of watersheds in the U.S. currently listed as nutrient impaired provide a viable physical environment for trading nitrogen; 13% are suitable for phosphorus. Economic and institutional challenges would shrink that domain even further. Therefore, we find places with the ideal physical, economic, and institutional environments necessary for feasible WQT programs are virtual policy utopias — rare places with ideal environments. Fortunately, a growing literature provides the tools necessary to identify where these policy utopias are and to expand that domain through a better understanding about how to manage WQT programs more effectively.     

Reluctant pioneers in the European periphery? Environmental activism,food consumption and “growing your own”

East European food self-provisioning (FSP) has fascinated scholars of post-socialism ever since the early 1990s. In keeping with its predominantly economic and cultural conceptualisations, much of this research has been concerned with FSP’s role in household economy and with the social profile of its practitioners. In contrast to western conceptualisations of FSP as an opportunity to expand food activism and foster social justice and environmental sustainability, post-socialist FSP has rarely been considered as such. In Czechia, FSP is practised by 43% of citizens and many of them do so in a relatively environmentally friendly way. Yet, most food-related campaigns run by environmental NGOs (ENGOs) pay little attention to FSP and focus on market-based ethical consumerism and alternative food networks instead. Using insights from actor-network theory, this paper discusses how Czech ENGO activists engage with FSP through discourse and in practice. Based on ethnographic fieldwork and interviews with leading activists, we show that FSP does figure in non-food-related campaigns and that the FSP practised by activists themselves or the FSP carried out by relatives and relatives’ friends are not the same as the FSP on which they are reluctant to campaign. These differences, which include controllability and the time-consuming nature of practising FSP according to some of the activists’ ideals, help this paper to come to an initial understanding of why Czech ENGOs do not run campaigns explicitly focused on FSP at the moment and shed some light on how this could change in the future.     

Assessing the Impact of Pluriactivity on Sustainable Agriculture. A Case Study in Rural Areas of Beotia in Greece

Pluriactivity of farms, or part-time farming, is a common feature of agriculture in all countries regardless of their socioeconomic system and level of development. Currently, pluriactivity is related to the values of sustainable agriculture. The objective of this study is to delineate those specific characteristics of pluriactive farms that contribute to sustainable agriculture. In rural areas of Boetia in Greece, a socioeconomic survey was carried out on 114 farms to determine the types of farming applied. The results demonstrate that pluriactivity is a stable component of the agricultural structure in the rural areas of Boetia. It is widespread in plains, but its presence is more important in mountainous and semimountainous areas. The choice of young farmers is to opt for pluriactivity. Farm size does not differ between pluriactive and full-time farms. Pluriactive and full- time farms use the same level of input and get the same output for the same type of crop. However, pluriactive farmers under the same land-productive conditions are oriented toward a more extensive farming system, managing their land with crops that need less inputs. Considering these findings, it can be claimed that pluriactivity can contribute to diminishing the demand on natural resources in favored (level and irrigated) areas, to continue agricultural production in unfavorable (mountainous and semimountainous) areas, and to help the sustenance of the rural population.     

考虑救援时效的化工园区应急物资储备站点选址模型研究

针对化工园区的应急物资储备站点选址问题,在同时考虑经济因素以及救援效果的基础上,建立了多目标覆盖选址模型,同时引入了应急救援时效函数,以反映物资运输时间对救援效果的影响.最后将模型应用于江苏省南部的化工园区应急物资储存站点的选址问题进行算例分析,使用NSGA-II算法对模型进行求解,并采用TODIM法对得到的帕累托最优...     

A Regional Assessment of Windbreak Habitat Suitability

The Environmental Monitoring and Assessment Programwas initiated in 1989 by the United StatesEnvironmental Protection Agency to collect, analyze,and report quantitative, statistically unbiasedinformation about the state of the nation'senvironment on a regional basis. During a pilotprogram in Nebraska we measured a habitat suitabilityindex for a probability sample of 40 windbreaks andexpanded the results to estimate the potential valueof windbreaks as wildlife habitat in Nebraska. Theindex estimates the suitability of a windbreak ashabitat for wildlife including breeding birds, smallmammals, and deer. Index values range from zero toone, where a value of one indicates maximal habitatvalue. We estimated that 50% (±13% at 90%confidence) of windbreaks in Nebraska have a habitatsuitability index of 0.25 or less and that nowindbreaks have a suitability index greater than 0.6. Our results indicate that increasing the area ofindividual windbreaks is the most effective way toimprove their value as wildlife habitat. Monitoringwindbreak condition over time would alert wildlifemanagers to changes in the resource that might affectwildlife populations. Because our data were highlyvariable, the power to detect change in habitatcondition between two measurement periods was low. Amuch larger sample would be required to detect smallchanges in habitat condition. Variability may bereduced, and power increased, by carefully andconsistently constructing the sampling frame, keepingdata collection as simple as possible, appropriatelystratifying sample selection, and using a small numberof well-trained data collection teams. However, wesuggest adapting the index for use with aerialphotography in future efforts to evaluate windbreaksas wildlife habitat in extensive areas.     

Spatial Economic–Hydroecological Modelling and Evaluation of Land Use Impacts in the Vecht Wetlands Area

Wetlands provide many important goods and services to human societies, and generate nonuse values as well. Wetlands are also very sensitive ecosystems that are subject to much stress from human activities. Reducing the stress on wetlands requires a spatial matching between physical planning, hydrological and ecological processes, and economic activities. Spatially integrated modelling and evaluation can support this. The present study has developed a triple layer model that integrates information and concepts from social and natural sciences to address the analysis and evaluation of land-use scenarios for a wetlands area in the Netherlands, the Vecht area. This is the floodplain of river Vecht, located in the centre of the Netherlands. The study has resulted in a set of linked spatial hydrological, ecological and economic models, formulated at the level of grids and polders. The main activities incorporated in the system of models are housing, infrastructure, agriculture, recreation and nature conservation. The formulation of alternative development scenarios is dominated by land use and land cover options that are consistent with the stimulation of agriculture, nature or recreation. Two aggregate performance indicators have been constructed from model output, namely net present value of changes and environmental quality. The spatial characteristics of these indicators are retained in a spatial evaluation that ranks scenarios.     

水生植物对农田排水沟渠中氮、磷的截留效应

为有效阻控农田土壤流失氮、磷通过沟渠进入水体,通过动态模拟实验研究对比不同排水沟渠对农田流失氮、磷的截留作用,同时通过静态模拟实验重点探讨了水生植物对氮、磷在水－沉积物－水生植物这一微观系统中的截留机理.结果表明:沟渠中的水生植物茭白和菖蒲对氮、磷的截留和转化有明显的促进作用;水生植物的存在可以加速氮、磷界面交换和传递,从而使上覆水中氮、磷含量快速减少;沉积物间隙水中氮、磷含量的变化受界面交换、沉积物吸附、微生物转化及植物吸收等各方面因素影响,水生植物调整并加强氮、磷的各种转化,植物的存在使得间隙水中氨氮及磷酸盐含量降低并呈现规律变化.      

长白山低山丘陵区生态农业建设与小流域治理——以吉林省柳河试验区为例

吉林省柳河试验区是长白山低山丘陵区域的典型代表。本文在分析了该试验区的农业自然条件及其存在的主要问题的基础上,提出了生态农业建设与小流域综合治理的技术模式,并报道了初步实施结果