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1.
我国农业用水量约占全国总用水量的70%,其中灌溉用水占农业用水的90%以上.由于灌溉方式落后,输水渠道大多为土渠,加上工程老化失修与配套不全,农业灌溉水的利用率与利用效率很低.因此缓解水资源短缺的根本出路是发展节水农业,实施节水灌溉,大力开发与推广节水灌溉技术,按作物最佳需水要求进行灌溉,最大限度地提高用水效率. 相似文献
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基于面板VAR模型的新疆农业用水与农业经济增长的互动效应研究 总被引：5，自引：0，他引：5
新时期以"绿洲灌溉农业"为特征的新疆各地区农业的快速发展与农业用水比重必须下降的现实,使得探讨两者之间的相互关系尤为重要。本文基于1997-2011年新疆15个地州(市)面板数据,建立了农业用水量与农业经济增长的面板VAR模型,考察农业用水与农业经济增长的互动效应。研究结果表明:1新疆三个区域的农业用水和农业经济增长之间存在长期协整关系;2北、东、南疆的农业用水对农业经济增长的推动效应有明显差异,其中北疆地区农业经济增长效应最大,其次为东疆,再次为南疆;3农业经济增长对农业用水量的变化产生的效应南疆最明显,其次为北疆,东疆用水结构较为稳定,农业用水量变动最小。因此,依据各地农业用水与农业增长的短期与中长期因果关系建立科学灌溉制度与水资源政策,依靠节水技术,才能有效提高农业综合效益。 相似文献
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新中国成立以来,全国用水量随着灌溉面积增加而增长迅速,用水总量从1949年的1031亿立方米增加到2004年的5548亿立方米。尽管我国农业用水量占总用水量比重逐步下降,但仍然保持在60%以上。尽管基本实现灌溉用水总量零增长,但农业发展仍受到水资源短缺的约束。在分析农业水资源管理存在的主要问题基础上,着重探讨了高效节水及如何建立农业水资源管理机制。 相似文献
4.
随着自治区工业化、城市化的不断发展,自治区对水资源的利用提出了严格要求,在国家对黄河水资源实行统一调配的情况下,只能通过节水,确保工业、生活用水。作为国民经济基础的农业是用水的大户,农业用水占总用水量的90%以上,但农业对国民生产总值的贡献率仅为25%。因此必须采取措施实现节水灌溉,全面实施节水农业发展战略,推广先进灌溉技术,提高水资源的利用率,以农业节水促进工业化、城市化的发展。 相似文献
5.
河北省是中国重要的粮食生产基地,水资源极为短缺,地下水超采严重。本文依据2019年河北省地下水灌区620份问卷调研数据,采用“以电折水”方法计算现状水价,应用门限回归模型检验灌溉水价对灌溉用水量的门限效应,并采用双对数线性模型建立两阶段灌溉用水需求价格函数。研究表明：①2019年河北省地下水灌区现状灌溉水价偏低,为0.35元/m3,现状灌溉用水量比灌溉定额高61.01 m3/亩,说明水价有提升空间;②灌溉用水需求价格曲线拐点对应的水价门限值为0.33元/m3,低于拐点时弹性系数为-0.21,高于拐点时弹性系数为-0.69,说明第一阶段水价提高对节水的作用较弱,第二阶段水价提高对灌溉节水的激励效果显著;③灌溉定额对应的水价为0.67元/m3,当现状水价提升到定额水价时,与现状灌溉用水量相比,节水率为27.60%。本文建议采用灌溉定额管理制度,推行定额水价,以发挥灌溉水价对农业节水的杠杆作用,研究结论可为地下水灌区的农业水价综合改革提供理论依据。 相似文献
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辽宁省农业用水量约占全省总用水量的2/3,是水资源的最大用户,农业用水量最大,节水潜力也最大,所以进行辽宁省的节水潜力分析及制定适宜的农业节水措施是十分必要的。本文从渠系输配系统、田间灌溉及水分生产效率三个方面分析了辽宁省的农业节水潜力,并结合辽宁省农业节水现状,从农业种植结构、节水灌溉工程建设、大中型灌区节水改造、牧区节水灌溉、旱作节水农业、节水管理体系等方面提出了具体的农业节水措施。 相似文献
8.
我国是农业大国,农业用水约占总用水量的70％。在农业用水中,灌溉用水约占90％,灌溉水利用率约为43％,水分生产率不足1．0kg／m^3,与发达国家灌溉水利用率80％相比远远滞后。因此,发展节水农业已经成为我国农业发展的头等大事。 相似文献
9.
发展节水农业,一方面可以缓解水资源危机,满足生产和生活用水日益增长的需求,以保证人类社会得以继续存在和发展;另一方面是农业发展的自身需要。在全世界,所汲取到的地表水和地下水中有2/3被农业所使用,所以专家们认为,高效灌溉是实现水资源可持续利用的首要举措,农业中的节水量是最主要的非开采性水源。本文阐明了发展节水农业的必要性和紧迫性,分析了福建省节水农业存在的问题,综合考虑福建省自然地理、社会经济条件、水源情况、枉业发展状况和行政区界等诸多因素,确定了福建肖发展节水农业的指导思想和基本原则,制订了福建省节水农业发展规划,同时提出实现规划的保障措施。 相似文献
10.
灌溉是保证农作物高产最基本的技术措施。节水灌溉制度是农业高效用水的基础,文章对西藏的水资源利用现状及西藏节水灌溉制度研究现状进行了阐述,同时提出了西藏节水灌溉试验研究工作设想,目的是为了通过节水灌溉制度的研究,将西藏农业田灌溉量控制在可用水量范围内,为加快西藏城市化和工业化进程保护区域生态提供充足的水资源保证。 相似文献
11.
A research group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol-a chemical found in the skins of red grapes in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said. 相似文献
12.
《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
13.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
14.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
15.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
16.
Active biological molecules functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery disease diagnosis therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction. 相似文献
17.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
18.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
19.
Leah A. Lievrouw 《The Information Society》2000,16(2):155-159
This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment. 相似文献
20.
Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献