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801.
长期施肥对旱地土壤杂草种子库生物多样性影响的研究 总被引:3,自引:0,他引:3
为探讨长期施肥对旱地土壤杂草种子库生物多样性的影响,我们在安徽蒙城地区的一个长期肥料试验定位监测点开展了相关研究。采用镜检法对旱地土壤表层(0~15 cm)中土壤杂草种子的种类进行鉴定并计数,记录杂草种子22种,隶属15科。不同施肥处理区杂草种子丰富度以NP1/2K区最高(14.7种),PK区最低(10.7种);其中陌上菜(Lindernia procumbens)、栗米草(Mollugo pentaphylla)、醴肠(Eclipta prostrata)、泽星宿菜(Lysimachia candida lindl)四种杂草的种子密度较大,分别在不同的处理区占据优势;从整个试验区来看,烟台飘拂草(Fimbristylis stauntoni)在所有处理中的密度都比较大,处于优势地位。长期不同施肥方式下,农田土壤杂草种子库的物种多样性有显著差异:PK区Shanon-Wiener指数大于其他处理区,但是Simpson优势度指数最低;NPK区Simpson优势度指数最高;PK、CK区Pielou均匀度指数大于其他处理区。田间杂草种子库的群落结构及其物种组成也发生了一定的变化,Whittaker指数表明,与不施肥处理相比较,半量的P和缺N的影响最显著,缺P次之,缺K和平衡施肥则没有显著影响。Sorenson群落相似性指数和Bray Curtis指数聚类分析结果表明,与不施肥相比较,长期施用N、P、K肥能显著改变旱地土壤杂草种子库的组成。本研究表明长期平衡施肥处理更有利于维持和保护旱地土壤杂草种子库的生物多样性。 相似文献
802.
河川径流量的变化对水资源的开发利用和国民经济的发展具有很大的影响。采用Ko1mogorov-Smirnov检验方法对无定河流域两个主要水文站赵石窑站和白家川站逐月径流量序列进行正态性检验,在此基础上运用DFA分析方法,估算两站时间序列的α标度指数,预测该流域径流量的未来变化趋势及其持续性,并采用随机重排法对估算结果进行了稳定性检验。分析结果显示:赵石窑和白家川两站径流时间序列的α标度指数分别为0.52和0.56,均大于0.5,径流时间序列表现为较强的长程依赖性,表明无定河流域在过去近50a内径流量的总体上呈下降趋势,在未来一段时间内,还将持续一段时间。对原时间序列随机重排后,两站月径流序列的α标度指数都变小,分别为0.48和0.49,接近于0.5,进一步证明原序列确实存在着标度不变性。研究结果对流域的水资源规划、管理与合理利用有帮助。 相似文献
803.
工业园区的规划建设对当地及周边地区的土地质量将产生重要影响 ,因此有必要将生态型土地功能区的理念纳入工业园区的规划之中。工业园生态型土地功能区是依据自然及人工特征对生态型人工复合系统或人类聚居地进行人为划分的区域。该区域应使人们在各种社会经济活动中所消耗的物资和物化劳动获得较大的经济效益的同时 ,保持生态系统的动态平衡。生态型土地功能区区划的重要理论依据是 :在对区域生态调查的基础上 ,首先对土地生态适宜度和生态敏感性两方面进行评价 ,然后根据评价结果将生态性质相似的土地进行类聚 ,并按不同的用途对该区的土地进行功能区划。最后以常熟市国际工业园案例进行实例研究 ,通过分析结果可以认识到园区生态型土地功能区区划与经济协调发展是可行的 相似文献
804.
The World Summit on Sustainable Development (WSSD), held in Johannesburg during 26 August and 4 September 2002, was the biggest event of its kind organised by the United Nations to date. A major objective of the WSSD was to set out strategies for greater and more effective implementation of Agenda 21, negotiated in Rio ten years ago, than hitherto. An overview of the WSSD is presented in this chapter, including a scrutiny of its major outcomes.Discussion begins with a detailed account of major UN environmental conferences and related events, such as Doha and Monterrey conferences, that led to the WSSD, followed by a brief discussion of the deliberations that took place at the preparatory meetings (PrepComs) of the WSSD. A detailed account and scrutiny of the following, that are the main outcomes of the WSSD, is then given.The "Johannesburg Declaration on Sustainable Development", which is a political declaration mirroring the will of the international community to move towards sustainable development.The "Johannesburg Plan of Implementation", which is the core document of the WSSD containing an impressive list of recommendations for accelerating the implementation of Agenda 21."Type II partnerships", which are projects that allow civil society to contribute to the implementation of sustainable development.The increasingly important post-Rio issue of globalisation, which has serious implications for a number of issues directly or indirectly impinging on global sustainability, was an important element in the contextual background to the WSSD. Reference is made to some of these implications.Type II partnerships are an innovation of the WSSD. Although a good deal of confusion persists over their precise nature and modus operandi, they were nevertheless presented at the WSSD as powerful and more democratic instruments for the realisation of Agenda 21 objectives.The analysis shows that the Summit contributed at defining sustainable development more precisely. The Plan of Implementation is most instrumental in showing how to make resource use and the generation of pollution less unsustainable. In this way implementing the recommendations of the Johannesburg Summit offers an important defeat, worldwide. 相似文献
805.
突发公共事件应急预案支持系统的研究进展 总被引:3,自引:9,他引:3
在分析当今公共安全形势日益严峻的背景下,回顾突发公共事件应急辅助系统国内外的发展状况,指出现有应急辅助系统的进展和不足,并阐明建立应急预案支持系统的重要性。通过对应急预案在文本预案、图文预案以及推演预案3个不同发展阶段的分析,分别评述3种预案支持系统的特点和缺陷,着重对推演预案支持系统在可视化、数字化以及智能化领域的研究进行分析,并以此为基础建立具有预案管理、预案自动生成、预案模拟演示、预案执行跟踪以及预案评估5大模块的突发事件应急预案支持系统,以期通过3S及人工智能等技术的应用不断完善系统,并从功能、技术及系统3个层面,积极探索应急预案支持系统未来可能的研究方向。 相似文献
806.
Hallett J. Harris Paul E. Sager Sumner Richman Victoria A. Harris C. Jarrell Yarbrough 《Environmental management》1987,11(5):619-625
Continued resource degradation in various areas of the Great Lakes has led to doubts of the adequacy of conventional science and management approaches. The need for a more holistic approach, identified as an ecosystem approach, appears now to be more widely accepted although progress with implementation is slow. We argue here that ecosystem science is an integral part of an ecosystem approach and is a prerequisite to effective management planning.One of the problems of implementing an ecosystem approach is forging the link between ecosystem based research and management. For Green Bay, Wisconsin, USA, certain structural and functional qualities of the ecosystem have been used to define operational guides and to formulate management objectives. These objectives are being utilized in the development of a remedial action plan for Green Bay.Deceased 5 February 1986. 相似文献
807.
Daniel H. Hoggan 《Journal of the American Water Resources Association》1972,8(3):625-630
ABSTRACT As availability of funds in the federal budget for water development has decreased recently, pressure has increased for state and local governments to pay a larger share of the costs. In this situation a difficult question immediately arises-what is the capability of state and local governments to pay a larger share? Of course, there is no easy answer. Expenditures of public funds are policy outcomes of a government's political process in which political, economic, legal and other factors are involved in complex relationships. The traditional sources of capital funds for state and local governments include bond proceeds, tax revenues, and federal financial aid (state aid is also a major source of local government funds). The issuing of bonds is hampered by a variety of legal debt limitations, but there are means for circumventing the limitations. State and local governments vary widely in amounts of taxable resources available and in the extent to which these resources have been tapped. More effective use of revenue resources could be made in some cases. New sources of capital funds for water development ought to be considered-a fee on the use of water per se, for example. Costs associated with water use currently are imposed to cover development costs, but a state might impose additional use fees earmarked for a state water development fund. 相似文献
808.
809.
810.
长期施肥对五氯酚在红壤性水稻田中消解的影响研究 总被引:1,自引:0,他引:1
在种稻和未种稻2种条件下,研究了五氯酚(PCP,初始浓度85 mg/kg)在长期不同施肥处理红壤性水稻田中的消解特征.长期不同施肥方式为:不施肥(CK)、施无机肥尿素(N)、施有机肥(OM)和无机有机肥配施(N+OM).结果表明,到收割水稻时,在未种稻情况下,CK、N、OM和N+OM处理表层土壤中可提取PCP残留分别为28.3、 34.2、 19.3、 18.7 mg/kg,在亚表层土壤中可提取PCP残留分别为6.3、 9.1、 5.1和4.1 mg/kg;在种稻情况下,表层土壤中可提取PCP残留分别为19.4、 30.9、 16.7和8.7 mg/kg,在亚表层土壤中可提取PCP残留分别为3.7、 6.1、 2.6和2.8 mg/kg.长期单施有机肥或无机有机肥配施显著加速表层土壤中PCP的消解,减缓表层土壤中PCP向下迁移;长期施尿素抑制表层土壤中PCP的消解,加速表层土壤中PCP向下迁移.与未种稻相比,种稻对表层土壤中PCP的消解呈现不同程度的促进作用,除N处理外,在其它3种长期施肥处理(CK、OM、N+OM)中均达到显著的水平.同时,种稻显著减少表层土壤中PCP向下迁移.无论种稻与否,PCP在稻田系统中均能发生还原脱氯降解生成2,3,4,5-四氯酚 (2,3,4,5-TeCP)和3, 4, 5-三氯酚(3,4,5-TCP);在未种稻情况下, 2,3,4,5-TeCP是PCP脱氯降解的主要产物,而在种植水稻的情况下, 3,4 5-TCP是PCP脱氯降解的主要产物. 相似文献