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排序方式: 共有1331条查询结果,搜索用时 31 毫秒
971.
Dalgaard T Olesen JE Petersen SO Petersen BM Jørgensen U Kristensen T Hutchings NJ Gyldenkærne S Hermansen JE 《Environmental pollution (Barking, Essex : 1987)》2011,159(11):3193-3203
Greenhouse gas (GHG) emissions from agriculture are a significant contributor to total Danish emissions. Consequently, much effort is currently given to the exploration of potential strategies to reduce agricultural emissions. This paper presents results from a study estimating agricultural GHG emissions in the form of methane, nitrous oxide and carbon dioxide (including carbon sources and sinks, and the impact of energy consumption/bioenergy production) from Danish agriculture in the years 1990–2010. An analysis of possible measures to reduce the GHG emissions indicated that a 50–70% reduction of agricultural emissions by 2050 relative to 1990 is achievable, including mitigation measures in relation to the handling of manure and fertilisers, optimization of animal feeding, cropping practices, and land use changes with more organic farming, afforestation and energy crops. In addition, the bioenergy production may be increased significantly without reducing the food production, whereby Danish agriculture could achieve a positive energy balance. 相似文献
972.
973.
Zhang W 《Environmental monitoring and assessment》2007,124(1-3):253-261
Both direct and indirect ecological interactions may occur in an ecosystem with large numbers of taxa. Traditional food web
technique is a popular tool to measure the quality and health of the environment. Much of works must be done before constructing
a food web for an ecosystem especially with many taxa. This food web is generally specific for some ecological interactions
and fixed for a set of given species. It is therefore not an effective method for dynamic and prompt assessment of environment.
Ecological interactions and their interactive intensity may be detected by sampling biological taxa in the field and by detecting
various between-taxa distances or similarities. Network may clearly exhibit the complex interactions among biological taxa.
Statistic tests on various distance or similarity measures and computer designs are required to infer the {network. We develop
an algorithm and software to infer the network of direct or indirect ecological interactions in ecosystem. It is a prompt
and effective tool in monitoring and assessment of the environment. A redundant network may be inferred and drawn by computer
based on the statistic tests on sampling data or the pathway information given in HTML file. Dominant taxa may be found in
the network. In total of 16 distance and similarity measures, including Euclidean distance, Manhattan distance, Pearson correlation,
partial correlation, point correlation, linkage coefficients, Jaccard coefficient etc., are provided to detect taxa pairs
with significant parametric or nonparametric similarities, based on randomization tests and ordinary statistic tests. Criteria
to use distance and similarity measures are discussed. 相似文献
974.
土壤镉污染防治对策的研究 总被引:5,自引:0,他引:5
本文概述了国内外土壤镉污染治理技术成果,比较了各种不同技术的使用条件及特点,并简要说明了其原理。针对天津市镉污染现状,对一些镉污染防治对策进行了研究,并提出可行性建议和措施。 相似文献
975.
天津市地下水利用中的环境问题及其对策 总被引:9,自引:0,他引:9
本文对天津市地下水资源现状和存在的问题进行了系统分析,详细论述了天津市地下水资源开发利用过程中所发生的环境问题及其产生的影响,从水资源管理体制,污染控制,水价,调蓄蓄能等方面,针对性地提出了解决对策和措施,并对天津短缺的水资源的开发利用和环境生态协调发展,进行研究和探讨。 相似文献
976.
珠江广州河段漂浮垃圾分布特点及治理策略 总被引:1,自引:1,他引:0
通过对珠江广州河段水上漂浮垃圾不同时间打捞量、来源分布、及其构成成份的调查和分析,提出水上垃圾总量模型和打捞削减模型,并根据广州地区的特点,提出水上垃圾的治理必须加强源头宏观管理;增加河涌拦网设置;扩大江面垃圾打捞区域;强化水上环卫管理队伍监管能力等策略意见。 相似文献
977.
978.
Richard D. Horan Marc O. Ribaudo 《Journal of the American Water Resources Association》1999,35(5):1023-1035
In this paper, we review the physical characteristics of agricultural non point pollution and discuss the implications for setting appropriate pollution control objectives and designing incentive-based pollution control policies. First, we discuss that policy objectives must be designed carefully to ensure positive economic net benefits can be expected from pollution control. Next, we review several classes of incentives and recommend the use of design-based incentives (i.e., incentives based on variable input use, management practices, and land use) for controlling non point pollution. Cost-effectiveness requires that incentives elicit three types of responses from farmers: (1) use variable inputs at appropriate levels, (2) adopt appropriate management practices, and (3) make appropriate land use decisions at the extensive margin of production. If a set of incentives fails to induce the correct responses, the resulting runoff levels and hence ambient pollution levels and damages will be too large relative to policy goals. A review of existing programs suggests that greater program coordination and improved targeting of incentives are needed for further water quality improvements. Alternatively, properly designed market-based systems may be effective alternatives. These systems would reduce overall pollution control costs by allowing markets to allocate point source and non point source control costs more efficiently. 相似文献
979.
980.
我国海洋环境保护的法律原则和政策措施 总被引:2,自引:0,他引:2
通过对近年来我国海洋环境保护法律法规和一些政策措施的分析,论述了基本的法律原则和当前所采取的污染防治和生态保护措施,结果表明,国家通过加强立法、增加投入,实施重点污染物总量控制、加强海洋生态保护和实施重点流域污染防治计划、重点海域碧海行动计划等措施,在一定程度上减缓了沿海经济建设和海洋产业开发给海洋环境带来的压力,近岸海域环境污染加剧的趋势得到初步控制,局部海域的环境质量有所改善。指出了当前存在的主要问题是城市环境基础没施建设滞后、工业污染防治水平不高、海上污染事故应急能力不足等,并提出了相应的建议。 相似文献