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261.
Operational Indicators for Measuring Agricultural Sustainability in Developing Countries 总被引:7,自引:0,他引:7
This paper reviews relevant literature on the sustainability indicators theoretically proposed and practically applied by scholars over the past 15 years. Although progress is being made in the development and critical analysis of sustainability indicators, in many cases existing or proposed indicators are not the most sensitive or useful measures in developing countries. Indicator selection needs to meet the following criteria: relative availability of data representing the indicators, sensitivity to stresses on the system, existence of threshold values and guidelines, predictivity, integratability and known response to disturbances, anthropogenic stresses, and changes over time. Based on these criteria, this paper proposes a set of operational indicators for measuring agricultural sustainability in developing countries. These indicators include ecological indicators involving amounts of fertilizers and pesticides used, irrigation water used, soil nutrient content, depth to the groundwater table, water use efficiency, quality of groundwater for irrigation, and nitrate content of both groundwater and crops. Economic indicators include crop productivity, net farm income, benefit–cost ratio of production, and per capita food grain production. Social indicators encompass food self-sufficiency, equality in food and income distribution among farmers, access to resources and support services, and farmers knowledge and awareness of resource conservation. This article suggests that the selection of indicators representing each aspect of sustainability should be prioritized according to spatial and temporal characteristics under consideration. 相似文献
262.
江苏省环境系统特点及环境污染状况 总被引:3,自引:1,他引:2
江苏省自然特点为单一而脆弱,表面为平原为主,水域面积较大,山地少,森林覆盖率低,生物种类少,江苏省社会环境特点为人均资源少,经济基础好,交通发达,城市密集和人才优势明显;江苏省的废气,废水,固体,噪声污染日益严重。由于上述特点和原因,江苏省农业机械化,现代化程度较高,水产养殖业发达,但应进一步提高农业集约化程度和大力推广生态农业整治环境污染,利用天在河道进一步发展养殖业;江苏省工业轻,重并举以轻为 相似文献
263.
资源工程体系建设探讨——以三峡库区坡地资源开发保护体系建设为例 总被引:2,自引:1,他引:1
申元村 《长江流域资源与环境》1998,(2)
资源工程是实现社会经济发展的基本途径。资源开发体系和保护体系建设是构成资源工程体系的主要内容。文章阐述了如何设计一个资源开发和保护体系的总体思路(包括原则、目标、内容、行动、效益评估),并以长江三峡库区坡地资源利用保护为例,通过植物篱农林复合技术,使水土流失和环境退化基本得到了控制,经济产出比纯柑桔系统和纯粮食作物系统分别高出1/5和1/4,成为开发与保护融为一体、经济和生态相互促进的技术。这一技术值得在中国东部湿润半湿润区域推广。 相似文献
264.
SBR法废水处理技术分析 总被引:2,自引:2,他引:0
本文介绍了SBR法处理原理及特点,使用该工艺所需设备和监测手段,应用前景。证明了SBR法适应性强,处理效果好,投资动行成本低,是一种经济、实用的污水处理工艺。 相似文献
265.
Roger B. Long 《Journal of the American Water Resources Association》1985,21(4):553-564
ABSTRACT: Economic models sometimes indicate that irrigation water is misallocated in agriculture, especially when it appears that the marginal value product is higher in other uses (such as for hydro-power). Historically, trends tend to contradict this reasoning, however, especially since irrigation has grown from 20 million acres in 1940 to over 50 million acres in 1980. Results of this study tend to indicate that as agriculture becomes more and more intensive (in terms of inputs), irrigation is part of that long term trend. Further, major economic variables, such as output and investments in agriculture, appear to be more highly correlated with irrigated land than with dryland agriculture. Recent data indicate an upper limit of about 320 million acres for dryland farming in the United States, while no such constraint is apparent for irrigated agriculture. 相似文献
266.
The necessity of incorporating societal and environmental concerns into publicly funded agricultural initiatives in research, extension, and practice is increasingly evident. Agriculturalists are urged to acknowledge and respond to societal concerns before an insensitive and largely ill-informed urban majority assumes a dominant posture in agricultural policy. In recent history, the availability of unrealistically cheap energy encouraged the evolution of a form of commercial agriculture unfettered by sound ecological principles. At present, external, resource-intensive intervention of increasing magnitude is needed to compensate for the apparent ecological instability generated by practices such as intensive cereal management or conservation tillage practices. Polarization of the enterprises of plant and animal agriculture to enable centralized, concentrate-intensive, confinement feeding has disrupted the natural cycling of nutrients and carbon in the soil, encouraged the withdrawal of perennial forages from crop rotations, and invoked a widely ramifying network of agricultural and societal problems. Solutions to these problems must evolve from a holistic and far-reaching appraisal of causes, rather than from a piecemeal approach to individual symptoms. 相似文献
267.
BIOMONITORING OF AIR POLLUTION IN A SEASONALLY DRY TROPICAL SUBURBAN AREA USING WHEAT TRANSPLANTS 总被引:3,自引:0,他引:3
Air pollution has been identified as a serious problem throughout the world which causes tremendous loss to the crops by affecting plant growth and yield. Earlier, air pollution was restricted to urban and industrial regions. Over the last few decades, however, it has become evident that pollutants can be transported over long distances and hence their impact may be felt widely over rural areas. The present study was conducted to evaluate the impact of urban air pollution on suburban agriculture with respect to the changes in photosynthetic rate, stomatal conductance, water-use efficiency, plant height, numbers of tillers, leaves, ears and seeds, chlorophyll, carotenoid, protein, phenol, ascorbic acid, nitrogen and sulphate-sulphur contents and seed weight of pot-grown wheat plants (Triticum aestivum var. HUW 468) kept at different sites around Varanasi city receiving varying levels of pollution load. Mean concentrations of were monitored. The study clearly showed that plants are negatively affected by the ambient levels of air pollutants. Reduction in various parameters directly corresponded with the air pollution levels at different sites. 相似文献
268.
Uri ND 《Environmental monitoring and assessment》2001,66(3):293-312
Soil erosion has both on-farm and off-farm impacts. Reductionof soil depth can impair the lands productivity, and thetransport of sediments can degrade streams, lakes, and estuaries. Since 1933, soil conservation policies have existedin the United States. Originally they focused on the on-farmbenefits of keeping soil on the land and increasing net farmincome. Beginning in the 1980s, however, policy goalsincreasingly included reductions in off-site impacts of erosion.As a consequence of conservation efforts associated withexplicit U.S. government policies, total soil erosion between1982 and 1992 was reduced by 32% and the sheet and rillerosion rate fell from an average of 4.1 tons per acre per yearin 1982 to 3.1 tons per acre in 1992 while the wind erosion ratefell from an average of 3.3 tons per acre per year to 2.4 tonsper acre per year over the same period. Still, soil erosion isimposing substantial social costs. These costs are estimated tobe about $37.6 billion annually. To further reduce soil erosionand thereby mitigate its social costs, there are a number ofpolicy options available to induce farmers to adopt conservationpractices including education and technical assistance, financial assistance, research and development, land retirement, andregulation and taxes. 相似文献
269.
Integration of Case Studies on Global Change by Means of Qualitative Differential Equations 总被引:2,自引:0,他引:2
We present a novel methodology to integrate qualitative knowledge from different case studies on Global Change related issues
into a single framework. The method is based on the concept of qualitative differential equations (QDEs) which represents
a mathematically well-defined approach to investigate classes of ordinary differential equations (ODEs) used in conventional
modeling exercises. These classes are defined by common qualitative features, e.g., monotonicity, signs, etc. Using the QSIM-algorithm
it is possible to derive the set of possible solutions of all ODEs in the class. By this one can formulate a common, qualitatively
specified cause–effect scheme valid for all case studies. The scheme is validated by testing it against the actually observed
histories in the study regions with respect to their reconstruction by the corresponding QDE. The method is outlined theoretically
and exemplary applied to the problem of land-use changes due to smallholder agriculture in developing countries. It is shown
that the seven case-studies used can be described by a single cause–effect scheme which thus constitutes a pattern of Global Change. As a generally valid prerequisite for sustainability of this kind of land-use the presence of wage labor is shown to represent
a decisive factor.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
270.
The Thar Desert of western India is known for its rich and ancient culture system and traditions. The communities have long
been part of the Thar Desert ecosystem and have evolved specific strategies to live in harmony with its hostile environment.
This culture has provided several miracle plants of immense food and medicinal value to modern civilisation. The ancient rural
livelihood knowledge system reflects time-tested techno-scientific knowledge with a proven track record of sustainability,
especially during natural hazards like drought and famines. In addition, several of the traditional skills of local communities
in arts and crafts, music and instruments have made modern man aware of the art and techniques of sustainably utilising local
biological resources and preserving their biodiversity along with using waste products of the forests, without harming the
desert ecosystem. Traditional cultural and socio-religious values are fast dwindling under the impact of materialistic approach,
industrialisation and development. This paper endeavours to illustrate the need to assist and propagate indigenous rural livelihood
systems rather than mindlessly replace or abandon them as a result of state bureaucracies. 相似文献