基于WINDOWS平台的河南省农业气象情报系统   总被引：1，自引：0，他引：1  

王良宇  张雪芬 《气象与环境科学》2000,(3):40-41

介绍了河南省农业气象情报系统的设计风格、思路及基本功能、运作过程和文件组织。  相似文献   

内流河流域水资源利用对径流年际年内变化影响的分析——以塔里木河流域为例   总被引：10，自引：1，他引：9  

海米提  熊黑钢 《地理研究》2000,19(3):271-276

以塔里木河流域为例,探讨了干旱区内流河流域近40年来,由于人口增长、灌溉面积扩大、河流水资源引用程度日益增加等原因所引起的河流径流多年变化及年内变化等水文效应及其变化的原因。  相似文献   

NECT样带1984～1996土地利用变化分析   总被引：36，自引：6，他引：30  

康慕谊  江源  石瑞香 《地理科学》2000,20(2):115-120

在分区选择典型样点的基础上,从土地利用结构类型和土地利用强度等方面对中国东北带（ＮＥＣＴ）近年来的土地利用变化进行分析,揭示出样带上土地利用发生变化较剧烈的区域为农牧交错带,变化的原因主要是人类活动强度的增加。此结论对样带上的生态敏感区域制定土地利用开发与管理下策应具有意义。  相似文献   

湖南农业持续发展的生存资源优度评价   总被引：22，自引：1，他引：21  

李晖 《地理科学进展》2000,19(1):41-49

从耕地资源、水资源、水土资源匹配、气候资源、生物资源、农业生态环境质量等方面 ,研究了湖南省各县生存资源禀赋的特征 ,并进行了生存资源的优度排序、分类和区划。基本结论 :湘东、湘南、湘西山地区生存资源优于湘中丘陵盆地区和湘北洞庭湖平原区 ;人口密度小的县生存资源优于人口密度大的县。  相似文献   

常州市农业产业对生态环境的影响及治理对策   总被引：8，自引：1，他引：8  

黄宗楚  郑祥民  曹希强 《云南地理环境研究》2004,16(3):42-46

作为长江流域传统农业生产大市的常州，随着农业产业结构调整的不断推进，其生态环境的可持续发展正面临着严峻挑战。通过对常州市水质、土壤、空气、声等农业生态环境质量现状的实地调查分析，结合该地各农业产业对生态环境造成污染的不同特点，提出如要从根本上治理农业生态环境污染，农业产业布局的调整是非常重要的一个方面，并对此作了新的布局规划；此外，还指出完善环境管理和改善生产技术也是治理生态环境污染的两个重要对策。  相似文献   

Control of gas emissions in underground coal mines   总被引：4，自引：0，他引：4  

Klaus Noack 《International Journal of Coal Geology》1998,35(1-4)

A high level of knowledge is now available in the extremely relevant field of underground gas emissions from coal mines. However, there are still tasks seeking improved solutions, such as prediction of gas emissions, choice of the most suitable panel design, extension of predrainage systems, further optimization of postdrainage systems, options for the control of gas emissions during retreat mining operations, and prevention of gas outbursts. Research results on these most important topics are presented and critically evaluated. Methods to predict gas emissions for disturbed and undisturbed longwall faces are presented. Prediction of the worked seam gas emission and the gas emission from headings are also mentioned but not examined in detail. The ventilation requirements are derived from the prediction results and in combination with gas drainage the best distribution of available air currents is planned. The drainage of the gas from the worked coal seam, also referred to as predrainage, can be performed without application of suction only by over or underworking the seam. But in cases where this simple method is not applicable or not effective enough, inseam-boreholes are needed to which suction is applied for a relatively long time. The reason for this is the low permeability of deep coal seams in Europe. The main influences on the efficiency of the different degasing methods are explained. Conventional gas drainage employing cross measure boreholes is still capable of improvement, in terms of drilling and equipment as well as the geometrical borehole parameters and the operation of the overall system. Improved control of gas emissions at the return end of retreating faces can be achieved by installation of gas drainage systems based on drainage roadways or with long and large diameter boreholes. The back-return method can be operated safely only with great difficulty, if at all. Another method is lean-gas drainage from the goaf. The gas outburst situation in Germany is characterized by events predominantly in the form of ‘nonclassical' outbursts categorized as ‘sudden liberation of significant quantities of gas'. Recent research results in this field led to a classification of these phenomena into five categories, for which suitable early detection and prevention measures are mentioned.  相似文献   

Mineralogical study of base metal tailings with various sulfide contents, oxidized in laboratory columns and field lysimeters   总被引：7，自引：0，他引：7  

S. C. Shaw  L. A. Groat  J. L. Jambor  D. W. Blowes  C. J. Hanton-Fong  R. A. Stuparyk 《Environmental Geology》1998,33(2-3):209-217

 Oxidation of a flotation-derived, low-sulfide tailings containing approximately 0.4 wt.% S was compared with simultaneously oxidized tailings containing 1.0 wt.% S and 2.5 wt.% S to assess their acid generating characteristics. Each tailings type was exposed to oxidation for three years in laboratory columns and in lysimeter pits in the field. In these tailings the sulfide mineral of principal concern with respect to acid generation is pyrrhotite (Fe _1-x S). In past studies the alteration of pyrrhotite has been characterized by initial replacement with marcasite (FeS₂) and ferric iron sulfates, which are followed by development of ferric oxyhydroxides such as goethite and lepidocrocite. Macroscopic characterization of the tailings shows varying and progressive degrees of oxidation correlative with the three different sulfur contents. As expected, the tailings with the lowest sulfur content are the least oxidized, and those with the highest sulfur content have reacted the most. The column tests, which represent accelerated reaction conditions relative to those for the lysimeter pits, show much higher degrees of oxidation, and a markedly more distinct boundary between the oxidized and unoxidized zones; as well, differences among the three tailings types are more pronounced. Received: 31 October 1997 · Accepted: 27 May 1997  相似文献   

Experimental study of the stability of metals associated with iron oxyhydroxides precipitated in acid mine drainage     

S. Rose  A. M. Ghazi 《Environmental Geology》1998,36(3-4):364-370

Iron oxyhydroxide precipitates associated with acid mine drainage (AMD) from the Stearns Coal Zone in southeastern Kentucky were analyzed for their metal (Al, Cu, Pb, Mn, Ni, and Zn) content. The most concentrated metals within these sediments are nickel (27–32×10³μmol/kg), manganese (16–29×10³μmol/kg), and aluminum (13–22×10³μmol/kg) as determined by HCl-HNO₃ digestion. Metal concentrations associated with the organic fraction as determined by H₂O₂ digestion were generally far lower, with the exception of aluminum. "Batch" experiments (at initial pH=2.0) were used to analyze the stability of these metals associated with a contaminated soil. Aluminum was the most mobile of the metals, presumably the result of the formation of aluminum-sulfate aqueous complexes. The solubilization rates for nickel and iron were very similar, suggesting that nickel, unlike the other metals, coprecipitated with iron in these sulfatic oxyhydroxides. Received: 9 October 1997 · Accepted: 15 December 1997  相似文献   

西藏羊八井现代地下热水系统硫矿的成矿作用   总被引：15，自引：3，他引：12  

张锡根 《化工矿产地质》1998,20(1):1-10

通过对羊八井盆地地热流体的地球化学、气体成分、同位素特征以及泉华、岩矿等资料的研究 ,确认该地下热水溶液中的水主要来自大气降水 ,部分来自深部 ;矿质大部分源自对围岩的淋滤和溶解 ,少部分物质 ,如易挥发成分则与岩浆体有关 ;热源则由地壳浅部岩浆体供给。根据羊八井地热水成矿作用特点和矿化分布规律 ,提出成矿区主要位于地热流体卸压排泄系统成矿的论点 ,并建立了羊八井盆地地热水系统成矿概念模型。地热田内自然硫及其它硫化矿物的形成过程中微生物起着重要的作用  相似文献   

Pedogeochemistry of china and its significance in agricultural production     

龚子同  黄标  欧阳洮 《中国地理科学(英文版)》1998,8(4):299-308

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