城市化进程中的土地稀缺性与政府管制

研究目的:分析城市化进程中土地稀缺性的表现形式和形成原因,探讨政府管制工具.研究方法:比较分析法.研究结果:在城市化的推动下,城市中心、城乡结合部和农村地区的土地利用分别具有竞争特征、转型特征和低收益特征,并因此衍生出不同的土地社会问题.研究结论:政府管制是解决土地社会问题的重要工具,政府应以区域土地资产最大化和社会公正为原则,对不同类型地区实施有差异的管制政策.     

工业化、城市化影响下的农地质量变化研究

土地资源面临的压力也越来越大,土地质量问题也日益引起世界各国政府、国际组织和学者的普遍关注,土地质量评价也已经成为当前土地科学研究领域的一个新的热点[1]。该文首先构建了工业化、城市化影响下的农地质量评价指标选择的理论框架,以此为依据确定评价指标体系,并应用综合协调度模型,以江阴市为例进行了实证研究。研究结果表明,压力的增加和土壤肥力因子协调性的降低是综合协调度降低、农地质量退化的动因,但主要是由于压力的增加。     

健康城镇化发展研究

针对近年来地方政府过度"土地城镇化"的现象,从城镇化的概念和内涵入手,提出了健康城镇化应是人口城镇化、经济城镇化、土地城镇化、社会城镇化4个方面的协调发展;对1981～2004年我国的土地城镇化态势进行了分析.研究了土地城镇化与人口、经济城镇化之间的关系,发现经济城镇化是土地城镇化最根本的影响因素,指出人口和土地的城镇化都要以经济城镇化为基础,才能实现健康城镇化.     

Optimal Land Development with Endogenous Environmental Amenities

A spatially explicit model of the optimal timing and location of land development is presented that incorporates dynamic interactions between land development and water quality. Ignoring two-way interactions leads to a lower level of water quality, more development, and lower social welfare. The optimal pace and pattern of development can be achieved through the assessment of an impact fee that internalizes pollution damages and irreversibility costs. Our results demonstrate the importance of accounting for the spatial dimension of land use, the interdependence between land use and environmental quality, and development irreversibility in models of urbanization and amenity-driven growth.     

Investment planning under uncertainty and flexibility: the case of a purchasable sales contract*

Investment decisions are not only characterised by irreversibility and uncertainty but also by flexibility with regard to the timing of the investment. This paper describes how stochastic simulation can be successfully integrated into a backward recursive programming approach in the context of flexible investment planning. We apply this hybrid approach to a marketing question from primary production which can be viewed as an investment problem: should grain farmers purchase sales contracts which guarantee fixed product prices over the next 10 years? The model results support the conclusion from dynamic investment theory that it is essential to take simultaneously account of uncertainty and flexibility.     

Determining the economic gains from regulation at the extensive and intensive margins

Among the second-best approaches for the regulation of pollution,little attention has been paid to the distorting effect of intensivemargin policies on the extensive margin. This article shows,within a dynamic framework, that regulation of the intensivemargin has to be complemented by regulation of the extensivemargin. Depending on the elasticity of the pollution functionwith respect to nitrogen use, the appropriate regulation atthe extensive margin is zero, a tax or a subsidy. We show empiricallythat combining a nitrogen tax with land-use taxes is about 18per cent more cost efficient than a nitrogen tax alone and 58per cent more efficient than off-site abatement in the formof groundwater treatment.     

Effects of an animal disease shock on meat markets and producer income

This paper simulates pig producer and slaughterhouse income losses due to a classical swine fever outbreak in Finland. The analysis explicitly takes into account that an outbreak of a highly contagious animal disease can shrink export demand for pig meat. After having observed the disease and its impact on pig meat price, producers can optimize animal stocks thought insemination decisions, which affects the number of animals in a dynamic manner. The income losses of pig industry were estimated to be less than €30 million. The losses were mainly due to price movements caused by an export demand shock. The results suggest that if the outbreak causes distortions in meat trade, the disease can cause substantial losses to the industry even if it has directly a small impact on the number of animals on farms. We also found that the optimization could reduce disease losses significantly, even more than 50%.     

衡阳市城镇化与土地利用协调发展研究

近年来,衡阳市城镇化进程加速,城镇规模和占地面积不断扩大,但城区片面扩展和城区土地低效利用影响到区域经济的可持续发展;试图通过对衡阳市1996～2004年城镇化和土地利用情况的分析,揭示衡阳市城镇化过程中土地利用的特征及其存在的问题,并提出相应的对策。     

近50年湖北省耕地动态变化及其驱动力分析

利用湖北省1952-2003年的统计和普查数据,分析了湖北省耕地数量动态变化及区域差异,并进一步探讨了影响耕地动态变化的驱动因子.结果表明:近50年,湖北省耕地数量变化经历了一个由短期增长到持续减少的动态变化趋势,区域差异明显,其中经济发展、人口增加、产业结构调整、政策等构成了耕地数量变化的主要驱动因子.     

我国城市环境地质研究现状及应注意几个问题

在分析我国城市环境地质研究现状的基础上,提出了在城市环境地质研究中,应注意将环境地质和地球化学、地球物理、"3S技术"等学科结合起来,不断吸收新方法新技术,并放宽视野,从城市化发展的趋势出发,着眼于"大城市"、城市群的环境地质研究,使城市环境地质研究真正为城市可持续发展和城市居民生活质量的提高做出更大的贡献.