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宁夏在水土流失治理方面探索了许多模式,取得了一定的成绩,但仍存在小流域治理经济效益不高等问题。在分析宁夏小流域治理现状的基础上,论述了实施小流域分类治理的意义,提出了不同小流域治理模式适宜的建设区域及基础条件。建议根据宁夏不同区域的自然基础条件、经济发展需求等,对小流域实施分类治理,并做好整体规划;以建设生态经济型小流域为主,开展多种形式的小流域治理;在流域经济建设方面,探索形成小流域治理的投资体制和运行管理机构。 相似文献
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北京市生态清洁小流域建设理论与技术措施研究 总被引:5,自引:3,他引:2
20世纪80年代以来,北京市的小流域综合治理工作在遏制水土流失加剧的过程中发挥了重要作用。2004年以来,北京市水务局结合北京市水土流失的新特点,提出建设生态清洁小流域,即以小流域为单元,根据系统论、景观生态学、水土保持学、生态经济学和可持续发展等理论,结合流域地形地貌特点、土地利用方式和水土流失的不同形式,开展小流域综合治理。基于北京市小流域治理的实践经验与现代治理要求,我们进行了生态清洁小流域内涵的界定和建设技术体系的探讨,并采取定性与定量相结合的方法,在大量调查研究基础上对生态清洁小流域"三道防线"的划分原则、指标体系及其治理措施体系做了深入的研究。 相似文献
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密云县山区小流域综合治理效益评价方法初探 总被引:1,自引:0,他引:1
密云县长期以来坚持以水源保护为中心进行小流域综合治理,取得显著成效,但小流域治理效益的数量化评价依然是一个亟待解决的问题。基于41条小流域1 700余个数据,综合运用统计分析方法,计算了研究区小流域治理效益的数量化评价指标。结果表明,小流域治理效益得分可以通过不同措施的工程量进行回归计算,计算值与实际值无显著差异,可以根据小流域治理中采取不同措施的工程量初步预测治理效益。生态清洁小流域建设思路符合北京市小流域治理工作需要,能够带来更大的蓄水和保土效益。 相似文献
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门头沟区生态清洁小流域建设与管理实例 总被引:1,自引:0,他引:1
北京市门头沟区从2002年开始进行生态清洁小流域建设工作,通过几年的治理,大大改变了山区小流域脏、乱、差的环境状况,真正意义上实现了小流域的"生态、和谐、繁荣"的目标。门头沟区生态清洁小流域建设主要有纯生态型和生态旅游型两种模式,其管理主要有村委会管理和景区管理处管理两种模式,它们分别适用于不同的情况。指出了生态清洁小流域建设存在的问题及解决方案,旨在为北京市下一步生态清洁小流域建设工作提供借鉴和参考。 相似文献
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Characterization of aroma compounds of chinese "Wuliangye" and "Jiannanchun" liquors by aroma extract dilution analysis 总被引:1,自引:0,他引:1
Aroma compounds in Chinese "Wuliangye" liquor were identified by gas chromatography-olfactometry (GC-O) after fractionation. A total of 132 odorants were detected by GC-O in Wuliangye liquor on DB-wax and DB-5 columns. Of these, 126 aromas were identified by GC-mass spectrometry (MS). Aroma extract dilution analysis (AEDA) was further employed to identify the most important aroma compounds in "Wuliangye" and "Jiannanchun" liquors. The results showed that esters could be the most important class, especially ethyl esters. Various alcohols, aldehydes, acetals, alkylpyrazines, furan derivatives, lactones, and sulfur-containing and phenolic compounds were also found to be important. On the basis of flavor dilution (FD) values, the most important aroma compounds in Wuliangye and Jiannanchun liquors could be ethyl butanoate, ethyl pentanoate, ethyl hexanoate, ethyl octanoate, butyl hexanoate, ethyl 3-methylbutanoate, hexanoic acid, and 1,1-diethoxy-3-methylbutane (FD > or = 1024). These compounds contributed to fruity, floral, and apple- and pineapple-like aromas with the exception of hexanoic acid, which imparts a sweaty note. Several pyrazines, including 2,5-dimethyl-3-ethylpyrazine, 2-ethyl-6-methylpyrazine, 2,6-dimethylpyrazine, 2,3,5-trimethylpyrazine, and 3,5-dimethyl-2-pentylpyrazine, were identified in these two liquors. Although further quantitative analysis is required, it seems that most of these pyrazine compounds had higher FD values in Wuliangye than in Jiannanchun liquor, thus imparting stronger nutty, baked, and roasted notes in Wuliangye liquor. 相似文献
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The "oxygen paradox" of dinitrogen-fixing bacteria 总被引:6,自引:0,他引:6
N2 fixation by aerobic bacteria is a very energy demanding process, requiring efficient oxidative phosphorylation, while O2 is toxic for the nitrogenase complex. N2-fixing bacteria have evolved a variety of strategies to cope with this apparent "O2 paradox". This review compares strategies that azospirilla and other well-known N2-fixing soil bacteria use to overcome this O2 paradox. Attention will be given to the relationships between the natural habitat of these soil bacteria and their prevailing adaptations. In view of this knowledge the following questions will be addressed: are the specific adaptations observed in azospirilla sufficient to allow optimal proliferation and N2 fixation in their natural habitat? Could improving the O2 tolerance of the N2-fixing process contribute to the development of more efficient strains for the inoculation of plants? 相似文献
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试论将“水土保持”改称“水土生态保持”的科学性 总被引:3,自引:9,他引:3
我国“水土保持”一词的提出已有60多年的历史,而治理水土流失的历史则可以追溯到西周初期(公元前16~11世纪)。水和土是陆地生态系统重要的生态因子,而以水和土为首要立地条件的生态植被,是陆地生态系统的第一性生产者,也是水土保持生态效益的直接承担者,所以植被的保护和恢复是水土保持不可或缺的重要部分,生态保护和生态与环境的改善愈来愈成为水土保持不可分割的重要内容。从水土保持的历史和当今不断丰富的水土保持实践来看,应将传统的“水土保持”称谓改称“水土生态保持”,这样更符合水土保持学科发展的需要,能够反映当前水土保持实践,有利于提高全社会对水土保持生态建设的认知度,有利于水土保持的行业管理。 相似文献
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"数字黄土高原"到"数字水土保持" 总被引:3,自引:1,他引:3
立足于黄土高原水土保持与生态环境建设及其科学研究的要求和空间信息科学技术发展的最新动态,通过:数字黄土高原”建立的时代背景及其技术背景,讨论了“数字黄土高原”研究与建设的目标,基本内容,关键技术环节(包括数据库结构,数据集成方法,数据更新,元数据体系建设和数字共享机制)和推广应用等,初步讨论了“数字水土保持”及其与国家空间数据基础设施(NSDI)建设的关系。 相似文献
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对杨树 虎纹蛙 罗非鱼("林 - 蛙 - 鱼")生态农业模式进行了3年的研究.结果表明,"林 - 蛙 - 鱼"立体种养生态农业模式经济效益明显,250 m2种养池当年可产生经济效益4 800元左右."林 - 蛙 - 鱼"立体种养生态农业模式也取得了良好的生态效益和社会效益,表现在改善生态环境、维护生物多样性、带动农民发展生产、教育青少年等方面,实现了生态效益、经济效益和社会效益的同步发展. 相似文献
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龙南县实施生态立县战略取得了令人瞩目的成绩,但仍存在一些问题与不足。在论述生态龙南建设的重要意义、指出建设中存在的问题与不足的基础上,认为加强生态龙南建设的途径和措施有:切实加强对生态龙南建设的领导;加大生态文化建设力度;制定生态龙南建设规划及年度实施计划;建立生态龙南建设的政策法规体系;制定生产建设项目并联审批制度;取缔有碍生态龙南建设的落后产业及工艺;整合与生态建设有关的项目资金,集中投入,发挥其乘数效应。 相似文献
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"3414"肥料试验模型拟合的探讨 总被引:174,自引:2,他引:174
以UNDP95-98年在河北唐山进行的27个3414冬小麦试验为例,研究了三元二次施肥模型与一元施肥模型对3414肥料试验结果的拟合情况。结果表明,三元二次施肥模型进行拟合试验成功率仅为56%,而采用一元施肥模型可以对全部试验进行数据处理。在同一试验中,与一元施肥模型相比,采用三元二次施肥模型计算的推荐施肥量偏高;根据一元施肥模型拟合计算分别有15%、44%、67%的点不需要施用N、P、K肥,而采用三元二次施肥模型则无法获得这一信息。因此,在3414试验中,一元施肥模型是三元二次施肥模型拟合的一种很好补充和优化手段。 相似文献
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Koskinen WC Rice PJ Anhalt JA Sakaliene O Moorman TB Arthur EL 《Journal of agricultural and food chemistry》2002,50(19):5368-5372
Sorption-desorption interactions of pesticides with soil determine the availability of pesticides in soil for transport, plant uptake, and microbial degradation. These interactions are affected by the physical and chemical properties of the pesticide and soil, and for some pesticides, their residence time in the soil. The objective of this study was to characterize sorption-desorption of two sulfonylaminocarbonyltriazolinone herbicides incubated in soils at different soil moisture potentials. The chemicals were incubated in clay loam and loamy sand soils for up to 12 wks at -33 kPa and at water contents equivalent to 50 and 75% of that at -33 kPa. Chemicals were extracted sequentially with 0.01 N CaCl(2) and aqueous acetonitrile, and sorption coefficients were calculated. Sufficient sulfonylaminocarbonyltriazolinone herbicides remained (>40% of that applied) during incubation to allow calculation of sorption coefficients. Aging significantly increased sorption as indicated by increased sorption coefficients. For instance, for sulfonylaminocarbonyltriazolinone remaining after a 12-wk incubation at -33 kPa, K(d) increased by a factor of 4.5 in the clay loam soils and by 6.6 in the loamy sand as compared to freshly treated soils. There was no effect of moisture potential on sorption K(d) values. These data show the importance of characterization of sorption-desorption in aged herbicide residues in soil, particularly in the case of prediction of herbicide transport in soil. In this case, potential transport of sulfonylaminocarbonyltriazolinone herbicides would be over-predicted if freshly treated soil K(d) values were used to predict transport. 相似文献