阜康市绿洲耕地变化与人口关系研究

以新疆干旱区中等城市——阜康市为研究区,采用1949～2005年的统计资料,运用Statistica 6．0统计软件,对其绿洲耕地的时空变化以及人口变化进行定量分析,得出50多年来人口对阜康市绿洲耕地数量和质量的影响。鉴于该绿洲的发展现状,提出了解决人地矛盾的对策和建议：控制人口总量、有效地保护耕地、提高耕地的利用效益、努力保护和节约使用水资源、提高土地的开发整理潜力等措施来减轻人口因子给耕地变化带来的影响。充分体现严格保护耕地、增加农业投入、促进农业科技进步、增强农业综合生产能力。图2,表1,参13。     

区域城市土地集约利用挖潜及模式研究

以不同区域内的14个省会城市为研究对象,从城市承载力和城市协调度两个方面挑选了20个指标,采用主成分分析的方法获得1997～2005年间各组主成分的贡献率和20个指标的影响因子,从贡献率和影响因子出发,分析了其变化规律。然后从区域城市土地集约利用模式出发,结合主要影响因子的变化情况,通过对比分析将区域城市土地集约利用模式划分为东部模式、中部模式和西部模式,并且各区域呈现出一定的均质性。表4,参6。     

长春市城郊无公害农业土壤环境中As含量状况调查研究

通过对长春市城郊无公害农业土壤环境中As含量水平调查,并进行了相对于无公害农作物产地环境质量标准中有关As的污染性评价,得出长春市城郊农业土壤环境中As的含量水平状况。长春市城郊无公害农业土壤环境中As含量存在不均衡性;浓度范围在4 12μg/g～18 60μg/g之间,平均值为12 17μg/g;污染呈现出从西南至东北的带状趋势;以《农产品安全质量无公害蔬菜产地环境要求》中GB/T18407 1-2001规定的As的质量标准作为评价标准进行评价,长春市城郊农业土壤环境中As的标准污染指数均小于1,属于未受As污染的土壤类型。图3,表2,参6。     

湖南省耕地安全问题探讨

湖南省自然条件优越,是全国的农业大省之一,但在耕地安全上存在不少问题,如耕地减少与人口增长的反差日趋明显、非农建设用地增长过快、对耕地的压力大、污染日趋严重、耕地质量下降等,制约了农业生产的前景与潜力,影响该省农业的可持续发展。出现这些问题的主要原因是,城镇化的发展与农村居民点的建设对耕地的冲击,农业生产结构的调整以及管理与政策上的不完善和疏漏。为实现湖南耕地安全,应大力加强全民耕地安全意识,加强对非农建设占用耕地的管理,大力调整农业结构,合理开发后备耕地资源等措施。图1,表2,参9。     

层次分析法逆序问题及其在土地利用适宜性评价中的应用

针对土地利用评价中常用的层次分析法,对于权重综合评判算子的保序条件和保序性进行了研究,并证明了加权乘积法是符合所有5种保序条件的算子.在此基础上,针对城镇土地防灾适宜性评价各因素的特点,对层次分析法做出发展,提出限定性因素评价模型,发展形成限定性层次分析法,并将之应用到泉州市场地防灾适宜性评价中.     

土地资源优化配置的物元模型

应用可拓学的理论和方法,对土地资源的特征及优化配置进行了分析,建立了土地资源优化配置的物元模型,为土地资源的优化配置和合理利用提供一种新的科学方法。     

土地利用现状的灰色聚类分析研究

为了对土地进行定量、定位配置和适宜度评价,本文采用灰色系统理论中的关联度和模糊数学中的聚类分析相结合而形成的灰色聚类分析方法对土地的集约化程度和利用效益进行了研究,得出了土地利用效益与集约化程度成正相关的结论。     

“Unfolding” Natural Resource-Use Information Systems: Fieldwork in Botswana

My research examines the performance of natural resource-use information systems. I question why such systems, despite receiving substantial financial and human investment, appear to have a weak impact on projects, programs, and policy intended for rural poverty alleviation in developing countries. Drawing on my understanding of the process of unfolding introduced by C. West Churchman, and its particular relationship to Habermasian constitutive interests, I reflect on my experiences of using the concept during fieldwork undertaken in Botswana. The concept is found useful on two fronts: first, it provides a purposeful guide for gathering and processing information/knowledge—what I have termed an epistemological intent; second, it provides a useful template for evaluating other information systems; in particular, the role of expertise—what I have termed an ontological intent. The process of unfolding, as I understand it, also provides an invitation for constructive (rather than self-indulgent) personal reflection: what might be termed a constitutive reflexive intent. By making information gathering and knowledge generation less mystical and a more transparent social activity, the conceptual and practical application of the process of unfolding can help toward retrieving inquiry as being a purposeful, openly political, and thereby less deceptive engagement: features which I believe are found particularly wanting in the business of rural development information gathering.     

哈尔滨市区土地资源的可持续利用问题及对策分析

哈尔滨市土地资源的可持续利用是区域社会经济可持续发展的重要基础和根本保证．     

Microhabitat use by the white‐clawed crayfish in a Tuscan stream

Habitat modification, pollution, overfishing, poaching, competition from non‐indigenous species, and diseases have led to the extinction in Europe of many populations of indigenous crayfish. Under the rationale that any programme of reintroduction should be preceded by a thorough understanding of habitat requirements of the species of concern, we studied the microhabitat use of an Austropotamobius pallipes population in Tuscany, central Italy. Microhabitat use was assessed for water depth, current velocity, substrate, percentages of boulders, underwater tree roots, and in‐stream vegetation cover. Results show that A. pallipes' habitat use is size‐partitioned. Smaller individuals mostly occupy stream edges in shallow waters with submerged roots, whereas larger individuals use deeper waters, often associated with boulders. Crayfish spatial distribution is restricted mostly to the microhabitats characterised by extensive cover and slow current velocity. The study highlights the importance of habitat heterogeneity and cover elements for the protection of this indigenous species.