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671.
新疆中低产田发展人工草地的初步研究 总被引:3,自引:0,他引:3
从新疆天然草地的利用,农业面临的问题出发,说明在绿洲内发展人工草地的必要性。针对全疆中低产田特点,将其分成7种基本类型。按类型总结出相应适生的饲草种类。通过人工种植这些饲草,达到合理利用改良耕地的目的,进而带动整个农业产业结构的调整,建立起适宜新疆农业发展的草地农业模式。 相似文献
672.
景观生态学在公路建设项目环境影响评价中的应用 总被引:5,自引:0,他引:5
景观生态学中的优势度原理在评价开发建设项目对生态系统完整性及其结构与功能稳定性方面具有很好的适用性,但在线型开发建设项目环境影响评价中很少应用。以公路建设为例,探讨了在线型开发建设项目生态环境影响评价中的应用。 相似文献
673.
674.
胡杨林的衰退原因与林地恢复策略 总被引:8,自引:0,他引:8
胡杨广布于地中海沿岸并呈带状东延至中国和蒙古人民共和国。目前,胡杨林已普遍呈不同程度退化,以塔里木盆地为例,垦伐等人为因素使林地总面积迅速减少。现场观测发现,一些林区缺乏胸径20cm以下的立木,而该地从1972年以来断绝洪水来源,显示洪水对幼苗补给可能存在相关,该地断绝洪水多年后,2002年重新出现洪泛过程,洪水退后出现大量的幼苗生长,从而证实洪水过程是胡杨幼林发生的必要条件。本文就此现象提出恢复部分林地的对策。 相似文献
675.
将石灰混凝处理后的沉淀泥渣进行回流,对石灰混凝法进行改进,研究改进后的石灰混凝法对城市污水二级出水中有机物的去除效果。结果表明,活性泥渣回流有利于提高石灰混凝法对城市污水二级出水中有机物的去除。回流位置在石灰投加前、复合絮凝剂投加后,最佳回流量为新泥渣产生量的100%~200%,活性泥渣回流的最佳pH为11.0~11.5;活性泥渣中CaCO3、Mg(OH)2、Fe(OH)3等沉淀物以及有机高分子絮体均有助于提高其对有机物的去除效果,其中Mg(OH)2沉淀物起主导作用;含循环泥渣的活性污泥回流,对有机物的去除效果无明显影响。 相似文献
676.
Exploiting Abstract Possibilities: A Critique of the Concept and Practice of Product Patenting 总被引:2,自引:0,他引:2
Hans Radder 《Journal of Agricultural and Environmental Ethics》2004,17(3):275-291
Developments in biotechnology and genomics have moved the issue of patenting scientific and technological inventions toward the center of interest. In particular, the patentability of genes of plants, animals, or humans and of genetically modified (parts of) living organisms has been discussed, and questioned, from various normative perspectives. This paper aims to contribute to this debate. For this purpose, it first explains a number of relevant aspects of the theory and practice of patenting. The focus is on a special and increasingly significant type of patents, namely product patents. The paper provides three general arguments against the concept and practice of product patenting. The first argument briefly considers the claim that patents are legitimate because they promote socially useful innovation. Against this claim, it is argued that product patents may hamper rather than promote such innovation. The second and main argument concludes that product patents are not adequately based on actual technological inventions, as they should be according to the usual criteria of patentability. The principal moral issue is that product patents tend to reward patentees for inventions they have not really made available. The final argument proposes a method for patenting the heat of the sun. Assuming that granting this patent will be generally considered absurd, the argument exposes a further, fundamental problem of the concept and practice of product patenting. 相似文献
677.
Marie-Claire Cordonier Segger 《Natural resources forum》2004,28(1):61-74
This article develops a practical proposal for progress on sustainable development law. It examines the prospects for an international sustainable development law to provide a framework for more effective, coherent governance. Sustainable development law is briefly defined and an analytical framework is provided. Different degrees of integration between economic, social and environmental law are described. Certain principles of international law related to sustainable development are also highlighted. It is argued that these principles may serve to guide law‐makers and jurists where social, economic and environmental law and policy conflict or overlap. Continuing, underlying questions of sustainable development governance are addressed and its global frameworks analysed. The article also focuses on the 2002 World Summit on Sustainable Development, held in Johannesburg in August‐September 2002, and its specific mandate for the United Nations Commission on Sustainable Development (UNCSD) to take related legal developments into account. The article advances a proposal: that governments, economic, social and environmental intergovernmental organizations and other actors establish a ‘network of inquiry’ with members from relevant groups, including legal and academic organizations, and other expert groups, in order to follow, research, analyse and debate legal developments in a balanced way. 相似文献
678.
Magdalena Svanstrm Morgan Frling Michael Modell William A. Peters Jefferson Tester 《Resources, Conservation and Recycling》2004,41(4):573
Environmental aspects of using supercritical water oxidation (SCWO) to treat sewage sludge were studied using a life cycle assessment (LCA) methodology. The system studied is the first commercial scale SCWO plant for sewage sludge in the world, treating sludge from the municipal wastewater treatment facility in Harlingen, TX, USA. The environmental impacts were evaluated using three specific environmental attributes: global warming potential (GWP), photo-oxidant creation potential (POCP) and resource depletion; as well as two single point indicators: EPS2000 and EcoIndicator99. The LCA results show that for the described process, gas-fired preheating of the sludge is the major contributor to environmental impacts, and emissions from generating electricity for pumping and for oxygen production are also important. Overall, SCWO processing of undigested sewage sludge is an environmentally attractive technology, particularly when heat is recovered from the process. Energy-conserving measures and recovery of excess oxygen from the SCWO process should be considered for improving the sustainability potential. 相似文献
679.
除水旱灾害之外,清代后期对湖南危害较大的灾种主要为虫灾,风灾、雹灾、冰冻雪灾偶有发生.本文对上述灾害的灾情进行了论述. 相似文献
680.