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491.
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. 相似文献
492.
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. 相似文献
493.
A Regional Assessment of Windbreak Habitat Suitability 总被引:4,自引:0,他引:4
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. 相似文献
494.
J. van den Bergh A. Barendregt A. Gilbert M. van Herwijnen P. van Horssen P. Kandelaars C. Lorenz 《Environmental Modeling and Assessment》2001,6(2):87-100
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. 相似文献
495.
水生植物对农田排水沟渠中氮、磷的截留效应 总被引:35,自引:1,他引:34
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. 相似文献
496.
497.
本文在深入分析大连市金州区发展外向型农业优势的基础上,探讨了该区外向型农业空间发展的原则和指导思想,初步界定了基地空间范围及未来的发展布局,为金州区外向型农业空间发展战略提供了理论依据。 相似文献
498.
文中论述了合理施肥对提高作物产量、改善品质以及净化与保护生态环境、实现农业可持续性发展的重要性与不可替代性,而施肥不当或滥用肥料不仅对土壤、植物养分平衡失调,作物产量与品质构成威胁,而且更重要的是作物吸收后所残留的肥料随着灌水或降水而产生径流、淋溶或侧渗,其累积效应对土壤和地表水、地下水易于造成污染,从而影响土壤环境与农业生态系统的稳定性、可持续性发展。为此,本文在肯定施肥对农业生产重要作用的基础上,重点探讨了施肥不当或滥用化肥,以城市生活垃圾、污水等为肥源所可能导致的土壤环境污染、对生态系统的危害性及其有效防治措施。 相似文献
499.
500.