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91.
Susan Power Bratton Raymond C. Mathews Jr. Peter S. White 《Environmental management》1980,4(5):433-448
Agricultural management in Cades Cove, an historic district in Great Smoky Mountains National Park, has affected natural resources both within the district and in the adjoining natural areas. Aquatic impacts of haying and cattle grazing included increases in water temperatures, turbidity, nutrient loading, and bacterial counts and decreases in benthic macroinvertebrate density and fish biomass. Wildlife populations, including groundhogs, wild turkeys, and white-tailed deer, have increased in the open fields and around the periphery of the historic district. Intensive deer foraging has removed deciduous seedlings and saplings from woodlots, lowering species diversity and favoring coniferous reproduction. Cades Cove has limestone habitats unique in the park, and both deer browse and cattle grazing may have disturbed populations of rare plant species. Effects on water quality are detectable at a campground 15 stream km from the agricultural area, and the effects of deer foraging extend about 1 km beyond the open fields.Since historic landscape preservation is presently a goal of the park, managing for open vistas in Cades Cove will require some sort of continuing disturbance. Conversion of cattle pastures to hayfields would reduce aquatic impacts but the deer herd might increase as a result of reduced competition for forage. Retarding old field succession would increase populations of native plant species dependent on sunlight, but would require government-funded mowing. Other options are discussed. Completely eliminating the effects of the historic district on adjoining areas may be impossible, at least under present economic constraints. 相似文献
92.
Quaternized agricultural by-products as anion exchange resins 总被引:3,自引:0,他引:3
The objectives of this study were the chemical modification of readily available, low-cost agricultural by-products to anion exchange resins and the selection of the best modified by-product for further use in anion removal. Resins were prepared through the quaternization of a series of 12 agricultural by-products with N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHMAC). Phosphate ion adsorption assays were conducted at pH 7 in order to compare adsorption properties among the by-products. Quaternized corn stover showed the highest phosphorus adsorption at 0.66 mmole/g. Since corn stover exhibited the best uptake of phosphate ion, it was compared to a commercially available, cellulose-based anion exchange resin. Additionally, adsorption capacities of quaternized corn stover for arsenate, chromate, and selenate were evaluated and adsorption efficiencies were determined in simulated wastewater samples. Our results indicate that modified corn stover demonstrates good adsorption uptake for arsenate and selenate and especially for chromate. 相似文献
93.
A Method for Improving the Management of Controversial Wetland 总被引:3,自引:0,他引:3
Merot P Hubert-Moy L Gascuel-Odoux C Clement B Durand P Baudry J Thenail C 《Environmental management》2006,37(2):258-270
Valley bottom wetlands in agricultural landscapes often are neglected in national and regional wetland inventories. Although
these areas are small, located in the bottomlands of the headwater catchments, and scattered in the rural landscape, they
strongly influence hydrology, water quality, and biodiversity over the whole catchment area. Valley bottom wetlands often
are considered as controversial wetlands. Awareness of the functional role of wetlands is increasing, in parallel with their
progressive disappearance in intensive farming landscapes. The need to improve tools for controlling wetland management is
a primary consideration for decision makers and land users. This article proposes a method for the inventory of valley bottom
wetlands. The method is based on the functional analysis of potential, existing, and efficient valley bottom wetlands (the
PEEW approach). Several indicators are proposed for checking the validity of such an approach. Potential wetlands are delineated
by means of a topographic index using topographic and pedoclimatic criteria computed from a Digital Elevation Model and easily
accessible databases. Existing wetlands are identified from observed surface moisture, the presence of specific wetland vegetation,
or soil feature criteria. Efficient wetlands are defined through a given function, such as flow or pollutant regulation or
biodiversity control. An analysis of areas at the limits between potential, existing, and efficient wetlands highlights land
cultivated or drained in the past, which currently represents negotiating areas in which rehabilitation and other intended
management actions can be implemented. 相似文献
94.
合肥市环巢湖地区种植业面源污染监测与评价 总被引:1,自引:0,他引:1
通过2016—2018年在合肥市环巢湖5个县区主要农田周边沟渠中采集水样,监测农田氮磷流失浓度,并评价该区域种植业面源污染状况.结果表明,这3年该区域种植业TN、TP流失的平均质量浓度分别为3.48 mg/L、0.602 mg/L,均高于地表水Ⅴ类水质标准.2016年与2017年TN、TP浓度差异不大,2018年较前两... 相似文献
95.
Alisa Salimova Jian e Zuo Fenglin Liu Yajiao Wang Sike Wang Konstantin Verichev 《Frontiers of Environmental Science & Engineering》2020,14(3):48
96.
Thodoris Dantsis Angeliki Loumou Christina Giourga 《Journal of Agricultural and Environmental Ethics》2009,22(3):197-216
Up to now, several scientific works have noted that the organic sector resembles more and more conventional farming’s structures,
what is widely known as the “conventionalization” thesis. This phenomenon constitutes an area of conflict between organic
farming’s original vision and its current reality and raises ethical and social questions concerning the structure of agricultural
systems of production and their interactions with the socio-economic and natural environment. The main issue of this dialogue
is the concept of sustainable agriculture, which for scientists and policymakers is a means to express their vision of a better
agriculture. In this article we focus on agricultural sustainability in the context of capitalist production as conducted
by the two subsystems of agro-industrial system. As we have proposed in this article, the relationship between organic agriculture,
defined by two essential components (prevention and direct marketing), and the agro-industrial complex, defined by two subsystems,
indicates the degree of agricultural sustainability. The investigation of this relationship can be extremely useful as it
may lead those involved in the discussion of sustainability to identify the key aspects of sustainable agriculture. In order
to investigate the interaction of organic farming with the agro-industrial complex, a survey was conducted in Central Macedonia,
Northern Greece, involving local organic farms. The results of our study indicate that a large proportion of organic producers
did not differ substantially from their counterparts in conventional agriculture in so far as their relationship with the
agro-industrial complex is concerned. Finally, this research highlights two scenarios for the evolution of organic farming.
The first is the full absorption of organic farming to the existing economic system and the second one is the development
of organic farming in a radically opposite direction to conventional farming. 相似文献
97.
Agriculture can be a major nonpoint source (NPS) of nutrient and pesticide contamination in the environment. Available databases
do not provide accurate and dynamic data on fertilizer and pesticide application, which limits the ability of complex watershed
models to simulate contaminant loads into impaired water bodies. A model for estimating agricultural nutrient and pesticide
input for watershed modeling has been developed. Climate, soils, and major agricultural operations are considered within the
model, so that it can be adapted to any watershed or subregion within a watershed. The timing of the agricultural operations
is a function of the weather data, providing realistic results at daily, monthly, or annual application rates. The model also
predicts irrigation demand and biomass production, which can be used to calibrate the model. Model output can be used in any
watershed model that considers agricultural land uses. Two case studies were evaluated, using grape vineyards in the Napa
River and strawberry production in Newport Bay as examples. The predicted time to maturity corresponded well with actual data.
Irrigation and fertilizer needs were very sensitive to weather input. Although the model can generate weather from long-term
averages, the simulated results are best when at least observed precipitation and temperature are provided, to capture extreme
events. The model has data for 98 crops and 126 pesticides, based on the California Department of Pesticide Regulation database.
The databases are easily modifiable by the user to adapt them to local conditions. The output from AgInput is much needed
for watershed modeling and for development of total maximum daily loads (TMDLs), based on realistic targets of irrigation,
nutrient, and pesticide inputs. The model is available for free download at . 相似文献
98.
99.
Manel Araoud Wahiba Douki Mohamed Fadhel Najjar Abderraouf Kenani 《Journal of environmental science and health. Part. B》2013,48(3):242-248
The aim of this study was to develop an analytical method for the determination of residues of organophosphorus and carbamate pesticides which are widely used in Tunisia. This method involves a liquid-liquid extraction procedure followed by liquid chromatography tandem mass spectrometry (LC/MS/MS) for the identification and quantification of compounds. Ionization of molecules was performed by the electrospray mode. Multiple reactions monitoring (MRM) was the acquisition mode used for the monitoring of two MS/MS transitions for each compound. The average recoveries obtained, at three different fortification levels, ranged between 65% and 106% for most of the pesticides studied, except for methamidophos (lower than 25%).The linearity of the method was in the range of 5 to 50 μ g/L with a correlation coefficient from 0.995 to 0.999, depending on the analyte. The estimated limit of detection and limit of quantification were 2 μ g/L and 5 μ g/L, respectively. The precision of the analytical procedure was satisfactory and the coefficients of variation, evaluated at three concentration levels were lower than 15% for most pesticides studied. The application of the method was investigated in a population of agricultural workers chronically exposed to various pesticides some of which, such as carbofuran, carbendazim, methomyl and pirimicarb, were detected in some serum samples. 相似文献
100.
Environmental degradation is a typical unintended outcome of collective human behavior. Hardin’s metaphor of the “tragedy of the commons” has become a conceived wisdom that captures the social dynamics leading to environmental degradation. Recently, “traps” has gained currency as an alternative concept to explain the rigidity of social and ecological processes that produce environmental degradation and livelihood impoverishment. The trap metaphor is, however, a great deal more complex compared to Hardin’s insight. This paper takes stock of studies using the trap metaphor. It argues that the concept includes time and history in the analysis, but only as background conditions and not as a factor of causality. From a historical–sociological perspective this is remarkable since social–ecological traps are clearly path-dependent processes, which are causally produced through a conjunction of events. To prove this point the paper conceptualizes social–ecological traps as a process instead of a condition, and systematically compares history and timing in one classic and three recent studies of social–ecological traps. Based on this comparison it concludes that conjunction of social and environmental events contributes profoundly to the production of trap processes. The paper further discusses the implications of this conclusion for policy intervention and outlines how future research might generalize insights from historical–sociological studies of traps. 相似文献