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Water transfers from agricultural to urban and environmental uses will likely become increasingly common worldwide. Many agricultural areas rely heavily on underlying groundwater aquifers. Out-of-basin surface water transfers will increase aquifer withdrawals while reducing recharge, thereby altering the evolution of the agricultural production/groundwater aquifer system over time. An empirical analysis is conducted for a representative region in California. Transfers via involuntary surface water cutbacks tilt the extraction schedule and lower water table levels and net benefits over time. The effects are large for the water table but more modest for the other variables. Break-even prices are calculated for voluntary quantity contract transfers at the district level. These prices differ considerably from what might be calculated under a static analysis which ignores water table dynamics. Canal-lining implies that districts may gain in the short-run but lose over time if all the reduction in conveyance losses is transferred outside the district. Water markets imply an evolving quantity of exported flows over time and a reduction in basin net benefits under common property usage. Most aquifers underlying major agricultural regions are currently unregulated. Out-of-basin surface water transfers increase stress on the aquifer and management benefits can increase substantially in percentage terms but overall continue to remain small. Conversely, we find that economically efficient management can mitigate some of the adverse consequences of transfers, but not in many circumstances or by much. Management significantly reduced the water table impacts of cutbacks but not annual net benefit impacts. Neither the break-even prices nor the canal-lining impacts were altered by much. The most significant difference is that regional water users gain from water markets under efficient management.  相似文献   

3.
Iran's Water Crisis: Cultural, Political, and Ethical Dimensions   总被引:2,自引:0,他引:2  
By the summer of 2001, most of Iranhad been suffering a three-year drought, theworst in recent history. Water rationing was inplace in Tehran and other cities, and largeproportions of the country's crops andlivestock were perishing. Yet many academicsand other experts in Iran insist that the watercrisis is only partly drought-related, andclaim that mismanagement of water resources isthe more significant cause. Underlying thisdiscussion is a complex of overlapping yetoften conflicting ethical systems – Iranian,Islamic, and modernist/industrialist – whichare available to inform water policy in Iran. Areview of the various arguments about thenature of the crisis and the range of solutionsthat have been proposed, including precedentsfrom traditional Iranian water management andthe ethics of water use in Islamic law,suggests that Iran's own cultural heritageprovides alternatives to wholesale adoption ofWestern models.  相似文献   

4.
Chesapeake Bay has been the subject of intensive research on cultural eutrophication and extensive efforts to reduce nutrient inputs. In 1987 a commitment was made to reduce controllable sources of nitrogen (N) and phosphorous (P) by 40% by the year 2000, although the causes and effects of eutrophication were incompletely known. Subsequent research, modeling, and monitoring have shown that: (i) the estuarine ecosystem had been substantially altered by increased loadings of N and P of approximately 7- and 18-fold, respectively; (ii) hypoxia substantially increased since the 1950s; (iii) eutrophication was the major cause of reductions in submerged vegetation; and (iv) reducing nutrient sources by 40% would improve water quality, but less than originally thought. Strong public support and political commitment have allowed the Chesapeake Bay Program to reduce nutrient inputs, particularly from point sources, by 58% for P and 28% for N. However, reductions of nonpoint sources of P and N were projected by models to reach only 19% and 15%, respectively, of controllable loadings. The lack of reductions in nutrient concentrations in some streams and tidal waters and field research suggest that soil conservation-based management strategies are less effective than assumed. In 1997, isolated outbreaks of the toxic dinoflagellate Pfiesteria piscicida brought attention to the land application of poultry manure as a contributing factor to elevated soil P and ground water N concentrations. In addition to developing more effective agricultural practices, emerging issues include linking eutrophication and living resources, reducing atmospheric sources of N, enhancing nutrient sinks, controlling sprawling suburban development, and predicting and preventing harmful algal blooms.  相似文献   

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This paper proposes to test the ethical acceptability of four styles of agricultural resource management: (1) contemporary industrial integrated systems agriculture, (2) modern industrial input dependent agriculture, (3) continuous traditional agriculture and (4) non-continuous (or swidden) traditional agriculture. The test of ethical acceptability is whether or not these styles of agricultural resource management embrace or are even compatible with that pattern of practical reasoning and interaction among ethical agents which we have independent theoretic grounds for preferring. The preferred sorts of practical reasoning and interaction are those which we find operating in ethical theories which are strongly committed to letting the discretion of ethical agents construct what is right for them to do. Thus the discussion distinguishes several different strengths of constructivist ethics relating them to the work of John Rawls, Immanuel Kant and Onora O'Neill. Then it argues for the theoretic preferability of one particular strength of constructivist ethic. The paper winds up by arguing that only traditional continuous agriculture embodies the preferred sort of practical reasoning and interaction among ethical agents. Further, I argue that this is the only style of agriculture which can embody such reasoning and patterns of interaction. Thus, as we consider the role of agriculture in our plans of international development, we have one reason to try to favor traditional continuous agriculture. To do otherwise would ignore the ethical superiority of the practical reasoning and patterns of interaction of traditional agriculturalists.  相似文献   

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Urban agriculturalists keeping mainly cross-bred dairy cattle in four different density areas in the city of Dar es Salaam, Tanzania were investigated as to whether they had information about the damaging effects of their animals on the environment. They responded to questions related to five issues of animal activity that damaged the urban environment. The findings revealed that, on average, all four socioeconomic groups possessed information about the damaging effects which their animals caused. Moreover, the people of the highest and quasi-medium socioeconomic status, who in turn kept the most cattle, were the most aware. Most agriculturalists keeping cattle, therefore, lived with the contradiction that they recognized the damaging effects of the animals. Using a conceptual model, several reasons are given as to why people persist in keeping the cattle. These reasons reside at four levels: government, ministry, city council and the individuals who keep cattle. After examining the reasons for keeping dairy cattle in the city, the author proposes changes at all four levels to reduce the serious urban environmental damage.  相似文献   

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Summary Prespa National Park is situated at the northwestern corner of Greece bordering Yugoslavia and Albania and covers 25,690 ha of which 8,114 ha are lake. The remaining area is forest, rangeland and arable land in the vicinity of twelve villages. The objectives of the park authority are to preserve the wetland with its special fauna of rare bird species, its flora, the geomorphological formations of the lake and the natural environment. The nucleus of the park is comprised by Lake Mikri Prespa and the surrounding wetland. It is in this wetland that an exceptional assemblage of rare and endangered species breed. However, the park is recently undergoing rapid development of its agroecosystems in terms both of higher subsidiary energy inputs, notably irrigation, and of acreage, i.e. of substituting some of the wetland for cropland. The objective of this study was to assess the potential environmental hazards from practicing agriculture in the park and to propose measures of abatement. Assessment was based on field surveys, administration documents and interviews. Cropland is not intensively used at present. Two thirds is covered by winter cereals and the remaining by other row crops (beans and potatoes). There are no deciduous orchards. Practices are carried out without regard for environmental conservation. Farmers' attitudes towards the wildlife range from indifference to hostility because they attribute the lag in their economic development to the past restrictions imposed by the National Park Administration. The main environmental consequences from the ongoing agricultural development in Prespa are assessed to be a dramatic increase of nonpoint agricultural pollution of the lake, with phosphorus and pesticides as the primary pollutants. Moreover, accidents in the use of pesticides may lead to immediate deterioration of the nucleus wildlife habitats. Since irrigated agroecosystems are there to stay and grow in subsidiary energy, measures are needed to prevent harmful consequences. Such measures are the alleviation of the land ownership problem, adoption of cultural practices to limit soil erosion, rational use of chemical fertilizers and pesticides and education of farmers. It is concluded that the internationally invaluable natural ecosystems of the park are definitely threatened by the development of the irrigated agroecosystems. The measures proposed will limit this threat and at the same time will help to perpetuate the productivity of the agroecosystems themselves.Mrs. M. D. Pyrovetsi is a lecturer in the Department of Biology and Professor P. A. Gerakis is Head of the Department of Agriculture; both are within the Aristotle University of Thessaloniki, Greece.  相似文献   

10.
In the final analysis, sustainable agriculture must derive from applied ecology, especially the principle of the regulation of the abundance and distribution of species (and, secondarily, their activities) in space and time. Interspecific competition in natural ecosystems has its counterparts in agriculture, designed to divert greater amounts of energy, nutrients, and water into crops. Whereas natural ecosystems select for a diversity of species in communities, recent agriculture has minimized diversity in favour of vulnerable monocultures. Such systems show intrinsically less stability and resilience to perturbations. Some kinds of crop rotation resemble ecological succession in that one crop prepares the land for successive crop production. Such rotations enhance soil organic processes such as decomposition and material cycling, build a nutrient capital to sustain later crop growth, and reduce the intensity of pest buildup. Species in natural communities occur at discrete points along the r-K continuum of reproductive maturity. Clearing forested land for agriculture, rotational burning practices, and replacing perennial grassland communities by cereal monocultures moves the agricultural community towards the r extreme. Plant breeders select for varieties which yield at an earlier age and lower plant biomass, effectively moving a variety towards the r type. Features of more natural landscapes, such as hedgerows, may act as physical and biological adjuncts to agricultural production. They should exist as networks in agricultural lands to be most effective. Soil is of major importance in agroecosystems, and maintaining, deliberately, its vitality and resilience to agricultural perturbations is the very basis of sustainable land use.  相似文献   

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Intensified surface mining, power generation, and smelting operations in the Hunter River lowlands, NSW, Australia have posed numerous new environmental management problems. Legislative controls over water, soils, and land use management have been clearly insufficient and remain so. The complex range of environmental changes is challenging government agencies as well as coal developers. While water demands are increasing in the region the proportionally greatest competitors are power generation and irrigation. Comprehensive regional water quality assessment is inadequate and divided between a number of agencies with fragmentary interests. Coal development inquiries signal further controversy over appropriate management solutions and are an ongoing phenomenon in the region. The early 1980s resource boom has been followed by lower rates of economic growth, which have resulted in disparate agency responses to major ongoing environmental questions. While issue attention cycles are often remarkably short in environmental management, matters of water, land, and air quality require intensive and ongoing monitoring and policy development.  相似文献   

13.
A number of distinct definitions ofsustainable agriculture have been proposed. In this paper we criticize two such definitions, primarily for conflating sustainability with other objectives such as economic viability and ecological integrity. Finally, we propose and defend a definition which avoids our objections to the other definitions.  相似文献   

14.
The sustainable intensification of agriculture   总被引:1,自引:0,他引:1  
Agricultural development is currently facing unprecedented challenges. With 800 million people already having insufficient access to food, population growth estimates project an even bleaker situation in the future. The article summarizes the major schools of thought regarding how to face the dilemma, and advocates sustainable intensification of agriculture, relying on integrated use of a wide range of technologies to manage pests, nutrients, soil and water. Local knowledge and adaptive methods are stressed rather than comprehensive packages of externally-supplied technologies. The article shows how regenerative, low-input agriculture, founded on full farmer participation in all stages of development and extension, can be highly productive. It is stressed that policy must not prescribe specific, concretely defined technologies or practices, as this would restrict future farmer options. Farmers and communities should be allowed and encouraged to adapt to changing conditions; what needs to be sustainable are local processes of innovation and adaptation.
The article highlights environmental and economic benefits resulting from sustainable intensification practices, for farmers as well as communities and nations with examples are taken from Africa, Asia and Latin America.
Despite the increasing success of sustainable agriculture, it is clear that the challenge remains to 'scale up' the process from small 'islands of success' to fundamental reform of both policies and policy formulation processes.  相似文献   

15.
Regulating water quantity and quality in irrigated agriculture   总被引:1,自引:0,他引:1  
This paper largely applies the theoretical model formulated in an earlier paper by the authors, of an input based approach to control an agricultural non-point-source pollution. The empirical problem includes a groundwater aquifer being polluted by several agricultural producers. In order to prevent degradation of the quality and depletion of the quantity of the water in the aquifer, a regulatory agency must intervene. The regulatory agency does not have all the information needed for decision making. The producers» use of water from a surface supply is recorded and additional water is pumped from the ground aquifer, the amount of which is unknown to the agency. The agency also does not know the physical characteristics of the production process that is factored into the pollution process. The model evaluates two monitoring regimes (central and individual) and two regulatory tools (taxes and quotas) associated with each regime. Individual monitoring was found to be superior to central monitoring, both in terms of the physical characteristics of the problem (water quality and quantity) and in terms of regional income. For both the central and the individual monitoring regimes, the optimal paths of the state variables reach steady-state values relatively early, with values in the individual monitoring reaching the steady-state earlier than in the case of central monitoring. The optimal path of investment in monitoring equipment suggested investment in monitoring equipment as early as possible.1998 Academic Press  相似文献   

16.
Groundwater quality: Responsible agriculture and public perceptions   总被引:1,自引:0,他引:1  
The chief sources of groundwater contamination on farms come from point sources and diffuse sources. Possible point sources are feedlots, poorly-sited manure piles, septic sewage-treatment systems—all of which can release nitrate, phosphates and bacteria— and sites of chemical spills. Diffuse sources are typified by excess fertilizer leaching from a number of arable fields. The basis of quality standards for drinking-water is discussed in relation to common contaminants present on farms. Samples of drinking-water were collected in 1991–1992 from wells on about 1,200 farms in order to study the quality of rural groundwater in Ontario. Analysis showed that approximately one third of wells were contaminated with bacteria, 14% were contaminated with nitrate, two wells were contaminated with pesticide, but 40% were considered unsafe because of the presence of at least one contaminant. These values were similar to those reported for similar regions in the U.S. There was no significant effect of agricultural practice on the proportion of contaminated samples. One response of Ontario's farmers to information on water quality has been to initiate their own program, the Environmental Farm Plan, which has 23 modules by which the risk of environmental contamination can be assessed. Government policies for agriculture can be expected to influence farming practices. However, the literature suggests that the consequences of policies aimed at reducing environmental contamination are poorly understood, not least because the instruments used for implementation can have widely differing impacts. The need for discussions on the ethics surrounding the relationship between food producers and consumers with regard to environmental contamination is identified.  相似文献   

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本文对水危机及全球水源状况进行了分析,为保护人类水资源与生态环境进行了有益的探索。  相似文献   

19.
After the last few decades in which the importance of 'local' knowledge has been emphasized, attention must now turn to better understanding how such knowledge is communicated to certified experts (scientists) and vice versa. This paper examines how expert knowledge is co-produced in agriculture by local and non-local experts for the benefit of both. The argument is informed by an empirical case study of sustainable farmers and agriculture professionals in Iowa. While much has been written about how the conventional and sustainable models of agriculture rest upon different epistemological orientations, little has yet been said about how those different experts (local and certified) interact with each other. Building upon the work of H. M. Collins and Robert Evans, and their tripartite model of expertise (of no, contributory, and interactional expertise), I investigate the different forms of expertise that exist within agriculture. In doing so, specific focus is placed upon interactional expertise for creating meaningful exchanges (or interactions) between scientists and non-scientists.  相似文献   

20.
The characteristics and role of the family farm have profoundly influenced the quality of human ecology. Considerable debate exists about the role of the family farm in the United States. This article attempts to clarify aspects of this debate by: (a) examining various definitions of the family farm and the conclusions that flow from these definitions, (b) presenting results of a structural analysis of American agriculture to better understand the origins of the debate and the relationship between people and agriculture, and (c) discussing the relevancy of some data and concepts used in evaluating the consequences of the structure of the agricultural sector.  相似文献   

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