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631.
The Ethical Contract as a Tool in Organic Animal Husbandry   总被引:1,自引:3,他引:1  
This article explores what an ethicfor organic animal husbandry might look like,departing from the assumption that organicfarming is substantially based in ecocentricethics. We argue that farm animals arenecessary functional partners in sustainableagroecosystems. This opens up additional waysto argue for their moral standing. We suggestan ethical contract to be used as acomplementary to the ecocentric framework. Weexpound the content of the contract and end bysuggesting how to apply this contract inpractice. The contract enjoins us to share thewealth created in the agroecosystem (by ourjoint contributions) by enjoining us to carefor the welfare and needs of the individualanimal, and to protect them from exploitation(just as human co-workers should not beexploited). The contract makes promoting goodanimal welfare a necessary condition forbenefiting farm animals. Animals for their partare guaranteed coverage under the contract solong as they continue to contribute to thesystem with products and services.  相似文献   
632.
Brazil produces approximately 242,000 t of waste per day, 76% of it being dumped outdoors and only 0.9% recycled, including composting, which is an alternative still little known in Brazil. In search of a better destination for residues produced by domestic activities, composting stands as a feasible alternative. Organic compost from waste may be used for various purposes, among which are soil recovery, commercial production, pastures, lawns and reforestry and agriculture. However, the quality of the compost determines the growth and the development of plants. The effect of compost made from urban waste on corn plant (Zea mays L.) growth was investigated. Two types of compost were used: the selected compost (SC), produced from organic waste selectively collected; and the non-selected compost (NSC), taken from a 15-year-old cell from the Canabrava land-fill, located in Salvador, Bahia, Brazil (altitude 51 m, 12°22′–13°08′S, 38°08′–38°47′W). Corn was seeded in polyethylene pots, with soil-compost mixing substrate in the proportion of 0, 15, 30, 45 and 60 t ha−1 equivalent doses. Chemical analyses of the compost and growth properties of the plant like chlorophyll content; height and stem diameter; aerial and radicular dry biomasses, were used to evaluate compost quality. Plants cultivated with SC presented a superior gain, being of 52.5% in stem diameter, 71.1 and 81.2% in root and stem biomasses, respectively. Chlorophyl content alterations were observed in plants from treatments using 30 t compost ha−1 dose onwards. Conventional and multivariate statistical methods were used to evaluate these results. The beneficial action of organic compost in plant growth was confirmed with this research.  相似文献   
633.
The results from three long-term field manipulation studies of the impacts of increased nitrogen deposition (0–120 kg N ha?1 yr?1) on lowland and upland heathlands in the UK were compared, to test if common responses are observed. Consistent increases in Calluna foliar N content and decreases in litter C:N ratios were found across all sites, while increases in N leaching were not observed at any site over the range 0–80 kg ha?1 yr?1. However, the response of Calluna biomass did vary between sites, possibly reflecting site differences in nutrient status and management histories. Five versions of a simulation model of heathland responses to N were developed, each reflecting different assumptions about the fate and turnover of soil N. Model outputs supported the deduction from mass balance calculations at two of the field sites that N additions have resulted in an increase in immobilisation; the latter was needed to prevent the model overestimating measured N leaching. However, this version of the model significantly underestimated Calluna biomass. Model versions, which included uptake of organic N by Callunaand re-mobilisation of N from the soil organic store provided some improvement in the fit between modelled and field biomass data, but re-mobilisation also led to an overestimation of N leaching. Quantification of these processes and their response to increased N deposition are therefore critical to interpreting experimental data and predicting the long-term impacts of atmospheric deposition on heathlands and moorlands.  相似文献   
634.
Many Superfund/hazardous chemical sites include waterbodies whose sediments contain hazardous chemicals. With the need to assess, rank, and remediate contaminated sediments at such sites, as well as in other waterways, regulators seek a simple, quantitative assessment approach that feeds easily into a decision‐making scheme. Numeric, co‐occurrence‐based “sediment quality guidelines” have emerged with the appearance of administrative simplicity. However, the very foundation of the co‐occurrence approach, based on the total concentrations of a chemical(s) in sediment, is technically invalid; its application relies on additional technically invalid presumptions. Use of technically invalid evaluation approaches renders any assessment of the significance of sediment contamination unreliable. This article reviews the technical roots and assumptions of the co‐occurrence‐based SQGs, the fundamental flaws in the rationale behind their development and application, and their misapplication for sediment quality evaluation. It also reviews concepts and approaches for the more reliable evaluation, ranking, and cleanup assessment of contaminated sediments at Superfund sites and elsewhere. © 2005 Wiley Periodicals, Inc.  相似文献   
635.
A disturbing trend among governmental agencies is the remediation of so‐called “nonhazardous” contaminated sediments/soils by deposition in minimum‐design Subtitle D municipal solid waste (MSW) landfills or landfills with equivalent design. This is done despite the fact that, in terms of protection of public health and environmental quality, the designation “nonhazardous” is misleading at best, and the fact that minimum‐design Subtitle D landfills as being allowed will not ensure protection of groundwater quality for as long as the buried wastes remain a threat. Although acknowledged in the regulatory documentation and exposed in the writings of a few in the scientific/engineering community, the environmental and public health issues that will inevitably be faced at minimum‐design Subtitle D landfills are underplayed, and even misrepresented, to the public. Discussion of relevant issues, as well as remarkable omissions, characterized the October 2004 United States Army Corps of Engineers (US ACE)/United States Environmental Protection Agency (US EPA)/Sediment Management Work Group (SMWG) conference,” Addressing Uncertainty and Managing Risk at Contaminated Sediment Sites.” This article addresses many of those neglected issues. © 2005 Wiley Periodicals, Inc.  相似文献   
636.
Three groups of data entry female visual display terminal (VDT) workers from Norway (n = 30), Poland (n = 33) and the USA (n = 29) were compared. Before intervention, the Norwegian group reported more neck pain compared with the Polish group. The Polish group reported less shoulder pain than both the U.S. and the Norwegian groups. The clinical examination documented fewer symptoms and signs of musculoskeletal illness among the Polish participants compared with the Norwegian and the U.S. groups. After intervention, the Norwegian group reported a reduction in neck pain while the U.S. group reported a reduction in shoulder pain. The Polish group reported an increase in neck, shoulder and forearm pain at follow-up compared to after intervention. The Polish group recorded higher flexion of the upper arm at follow-up parallel with an increase of pain in the upper part of the body. Visual discomfort showed variable results in the 3 countries.  相似文献   
637.
638.
The ground water denitrification capacity of riparian zones in deep soils, where substantial ground water can flow through low-gradient stratified sediments, may affect watershed nitrogen export. We hypothesized that the vertical pattern of ground water denitrification in riparian hydric soils varies with geomorphic setting and follows expected subsurface carbon distribution (i.e., abrupt decline with depth in glacial outwash vs. negligible decline with depth in alluvium). We measured in situ ground water denitrification rates at three depths (65, 150, and 300 cm) within hydric soils at four riparian sites (two per setting) using a 15N-enriched nitrate "push-pull" method. No significant difference was found in the pattern and magnitude of denitrification when grouping sites by setting. At three sites there was no significant difference in denitrification among depths. Correlations of site characteristics with denitrification varied with depth. At 65 cm, ground water denitrification correlated with variables associated with the surface ecosystem (temperature, dissolved organic carbon). At deeper depths, rates were significantly higher closer to the stream where the subsoil often contains organically enriched deposits that indicate fluvial geomorphic processes. Mean rates ranged from 30 to 120 microg N kg(-1) d(-1) within 10 m versus <1 to 40 microg N kg(-1) d(-1) at >30 m from the stream. High denitrification rates observed in hydric soils, down to 3 m within 10 m of the stream in both alluvial and glacial outwash settings, argue for the importance of both settings in evaluating the significance of riparian wetlands in catchment-scale N dynamics.  相似文献   
639.
Substantial amounts of NO3 from agricultural crop production systems on poorly drained soils can be transported to surface water via subsurface drainage. A field study was conducted from the fall of 1993 through 2000 on a tile-drained Canisteo clay loam soil (fine-loamy, mixed, superactive, calcareous, mesic Typic Endoaquoll) to determine the influence of fall vs. spring application of N and nitrapyrin [NP; 2-chloro-6-(trichloromethyl) pyridine] on NO3 losses from a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation. Four anhydrous ammonia treatments (fall N, fall N + NP, spring preplant N, and spring N + NP) were replicated four times and applied at 135 kg N ha(-1) for corn on individual drainage plots. Drainage occurred in all seven years. Seventy-one percent of the annual drainage and 75% of the annual NO3 loss occurred in April, May, and June. Fifty-four percent of the NO3 lost in the drainage occurred during the corn phase and 46% during the soybean phase. Annual flow-weighted NO3-N concentrations for the fall, fall + NP, spring, and spring + NP treatments averaged 14.3, 11.5, 10.7, and 11.3 mg L(-1) during the corn phase but annual NO3-N concentrations were still > or =10 mg L(-1) in three of six years for the spring preplant treatment. Averaged across the six rotation cycles, flow-normalized NO3-N losses ranked in the order: fall N > spring N + NP > fall N + NP > spring N. Under these conditions, NO3 losses in subsurface drainage from a corn-soybean rotation can be reduced 14% by spring N and 10% by late fall N + NP compared with fall-applied N. Nitrate losses were not appreciably reduced by adding NP to spring preplant N.  相似文献   
640.
Tillage erosion and its effect on soil properties and crop yield in Denmark   总被引:1,自引:0,他引:1  
Tillage erosion had been identified as a major process of soil redistribution on sloping arable land. The objectives of our study were to investigate the extent of tillage erosion and its effect on soil quality and productivity under Danish conditions. Soil samples were collected to a 0.45-m depth on a regular grid from a 1.9-ha site and analyzed for 137Cs inventories, as a measure of soil redistribution, soil texture, soil organic carbon (SOC) contents, and phosphorus (P) contents. Grain yield was determined at the same sampling points. Substantial soil redistribution had occurred during the past decades, mainly due to tillage. Average tillage erosion rates of 2.7 kg m(-2) yr(-1) occurred on the shoulderslopes, while deposition amounted to 1.2 kg m(-2) yr(-1) on foot- and toeslopes. The pattern of soil redistribution could not be explained by water erosion. Soil organic carbon and P contents in soil profiles increased from the shoulder- toward the toeslopes. Tillage translocation rates were strongly correlated with SOC contents, A-horizon depth, and P contents. Thus, tillage erosion had led to truncated soils on shoulderslopes and deep, colluvial soils on the foot- and toeslopes, substantially affecting within-field variability of soil properties. We concluded that tillage erosion has important implications for SOC dynamics on hummocky land and increases the risk for nutrient losses by overland flow and leaching. Despite the occurrence of deep soils across the study area, evidence suggested that crop productivity was affected by tillage-induced soil redistribution. However, tillage erosion effects on crop yield were confounded by topography-yield relationships.  相似文献   
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