退耕还林对农业生产结构影响的实证研究——以陕北吴起县为例

首先运用描述性统计方法从种植业、畜牧业和林业、渔业等几方面对退耕还林前后农业生产结构的变化进行分析;然后借助洛伦兹曲线和基尼系数,分别计算了吴起县退耕还林前后的农业生产结构合理化指数,得出退耕还林后吴起县农业生产结构合理化综合指数有所提高(由0.8270提高到0.8596),但仍有进一步调整的空间;特别是退耕还林前后劳动力合理化指数都偏低(分别仅为0.7426和0.7762),说明吴起县劳动力结构调整力度还有待加强。     

The necessity and countermeasures of developing China＇s Land Bank Investment Trusts

The problem of Land Bank financing channels＇ being single has become the obstacle that restricts the development of China＇s land bank financing market. In this paper, we discussed the necessity of developing Land Bank Investment Trusts, and considering at presented, the obstacles and countermeasures of the development of China＇s Land Bank Investment Trusts.     

浅析天然气转换后调压器的改造及运行管理

本文介绍了天然气转换后调压器改造的必要性、改造方法和运行管理重点。     

Proposed algorithm for the identification of land for consolidation with regard to spatial variability of soil quality

The quality of soil is one of the most significant factors having a real impact on the potential level of agricultural crops. Therefore, it is a significant element shaping the profitability of agricultural production in the specific area. Familiarity with spatial variability of soil quality classes in respective voivodeships has an impact on planning the development of agricultural areas and effective allocation of money to rural spatial restructuring. This element also provides important information in the process of consolidation works programming which takes place at the regional government level. This data is characterised by very long usability due to a small number of changes referring to classification of land entered into the land and building survey. Data on the quality and suitability of soil in the analysed area was acquired from the analysis of data from the land and building survey. Analyses were carried out in 3 poviats of Lublin voivodeship located in the eastern part of Poland covering an area of 501 132.9 ha, split into 610,160 plots. This paper presents an algorithm designed by the author for identifying areas in which land consolidation works should be performed, including its practical application using the adopted sample. The algorithm identifies areas characterised by the highest soil quality, which makes it possible to indicate areas where land consolidation work should first be undertaken.     

Drivers and projections of vegetation loss in the Pantanal and surrounding ecosystems

Modeling scenarios can help identify drivers of and potential changes in land use, particularly in rapidly changing landscapes such as the tropics. One of the places where most of the recent anthropogenic land use changes have been occurring is the "arc of deforestation" of the Amazon, where several scenarios have been constructed. Such modeling scenarios, however, have been implemented less frequently in wetland areas, but these are also undergoing rapid change. An example is the Pantanal, one of the largest wetlands on the planet located in the Upper Paraguay River Basin (UPRB). The UPRB is formed by the lowland (Pantanal) and the plateau (Cerrado and Amazon where the spring-fed rivers are). We used a spatially explicit model to identify drivers of vegetation loss in the Pantanal and surrounding area (UPRB) and estimated potential vegetation loss for the next 30 years. The model is probabilistic and considers that vegetation loss is contagious, so that the local rate of deforestation increases over time if adjacent sites are deforested, also taking into account the drivers identified in those locations. Our study is the first to simulate vegetation loss at property-scale, over 20,000 properties, for the entire UPRB in Brazil, taking into account the relationship between the plateau, where headwaters are located, and the lowland, where flooded-areas are concentrated. The drivers of vegetation loss identified for the lowland (distance to roads and rivers and elevation) differed from those for the plateau (distance to cities), demonstrating the relevance of analyzing areas separately. The cumulative rate of native vegetation loss projected for 2050 was 3% for the lowland and 10% for the plateau, representing losses of 6045 km² and of native vegetation area decreasing from 87% to 83% and 7960 km² from 39% to 35% respectively by 2050, if changes continue at the same pace and if the environmental legislation is followed. The projected vegetation loss in the UPRB forms a geographical arc, very similar to that observed in the Amazon, from the plateau into the lowland. The arc is directly related to areas with no or low flooding frequency because they are suitable for agriculture. The identification of this arc of vegetation loss calls for urgent conservation policies for this wetland and new perspectives for management.     

Land prices and land subdivision in Madina,Saudi Arabia; 1965–85

Summary

This paper is concerned with explaining the relationship between land prices and subdivision activity in Madina, Saudi Arabia. This article is not concerned with the effect of land prices on individual landowners, but rather on the supply of land in general. First it is necessary to explain the increase in land prices and why they have risen in real terms over time, what are the periods of growth and decline and what effects have they had on the supply of land for subdivision. This paper then explains the geographical variations in land prices and their influence on the distribution of land subdivision throughout the Madina area, especially in inner city areas and suburban areas.     

土地经营权体系的内部冲突与调适

研究目的:通过解释论调适由承包农户流转产生的土地经营权和以其他方式承包取得的土地经营权之间的体系冲突。研究方法:规范分析法。研究结果:土地经营权的性质界定应坚持一元论,将农户流转产生的和以其他方式承包取得的土地经营权一体界定为债权。两类土地经营权上设立的担保物权应统一定位为抵押权。以其他方式承包取得的土地经营权应类推适用《农村土地承包法》第41条,采登记对抗主义,期限五年以上的具备登记能力。"依法登记取得权属证书"不是该类土地经营权流转的效力性强制规定。研究结论:未来须在解释论和立法论上进一步研究土地经营权体系冲突如何化解。     

基于GWLR模型的不同栅格尺度下城市用地空间扩张驱动力研究——以徐州市为例

城市用地扩张驱动力存在空间异质性,从局部视角分析城市用地扩张驱动力对深入认识城市用地扩张过程及城市规划与管理具有重要意义。然而,在采用栅格数据分析城市用地扩张驱动力时,栅格尺度往往会影响驱动力研究的可靠性。因此,本文以徐州市中心城区为例,基于遥感影像解译数据,在分析研究区城市用地扩张特征基础上,分别采用30m×30m、60m×60m、90m×90m、120m×120m和150m×150m分辨率的栅格数据,运用能够反映驱动力空间异质性的地理加权Logistic回归模型(GWLR)对2005~2015年研究区城市用地空间扩张的驱动力进行分析,通过对比不同栅格尺度回归模型拟合效果确定最优栅格尺度,并分析最优栅格尺度下城市用地扩张驱动力。结果表明:GWLR模型可解决全局模型难以克服的空间异质性问题,GWLR模型结果优于Logistic回归模型;研究区城市用地空间扩张驱动力的最佳栅格尺度为90m×90m;2005~2015年研究区城市扩张为外延式扩张和飞地式扩张,主要沿交通干线向对外交通轴线及水系方向扩张;其城市扩张最主要受到高速公路、高速出口、一般公路、区中心和水系的距离的影响,到高速公路的距离对于研究区东部地区影响较强,到区中心和高速公路出口的距离在南部地区影响较强,到一般公路、水系的距离在北部地区影响较强,其余各变量也在不同的区域对城市用地扩张产生不同程度的影响。     

Land rights,rental markets and the post-socialist cityscape

Inefficiently organized, factory-dominated cityscapes have been one of the more enduring legacies of the twentieth century experiment with socialist central planning in Eastern Europe and the Soviet Union. Drawing on a unique survey of large, formerly state-owned urban industrial firms in Russia, we explore how land tenure reforms affect the pace at which this legacy is being erased. For various historical, political, and economic reasons, there is substantial variation across firms as to their ownership of the land on which they sit. Despite facing no additional formal constraints, those that do not own their plots rent them out at a lower frequency than those that have acquired private tenure to their land. The privatization of plots, in other words, promotes the development of a rental market that transfers land use rights away from socialist-era industrial users. We address the potential endogeneity of land tenure using a measure of regional variation in urban land policy and Communist party vote shares as instrumental variables.     

SEA making inroads in land-use planning in Brazil: The case of the Extreme South of Bahia with forestry and biofuels

In Brazil, incorporating the environmental dimension to the planning process is a challenging process. Planning has historically been carried without considering environmental protection concerns. The country's large development projects have engendered a discussion on the feasibility of these works given the conflicts with environmental policies. The strategic environmental assessment (SEA) is a tool that has the potential to integrate the sectoral, territorial and environmental perspectives to promote sustainable development, as shown by international experience. Its use has not yet been regulated in Brazil, only been voluntary initiatives, both public and private, have been implemented. This paper presents the structure and results of the SEA of the plans to expand silviculture of eucalyptus and biofuels in the Extreme South Region of Bahia state, in the Brazilian Northeast, in a context of sectoral planning dissociated from government guidelines for land use policy and environmental protection. It portrays a practical case of methodological proposal for the use of socio-environmental criteria to establish limits for land occupation by monocultures, for each of the municipalities of the study region, according to their specific climate, soil, relief and environmental preservation characteristics. Various alternatives were identified to ensure areas with greater productivity for small family farming and areas with potential for preservation. SEA helped to a better understanding of the effects of the expansion of the planting areas in each alternative, which was essential to help all stakeholders visualize the consequences of their strategies. Consequently, as results the SEA outlined a series of guidelines and restrictions for the various levels of government and the production sector. For instance, SEA suggested for Federal, State and Municipality governments that areas with better soil and climate conditions could be reserved for public policies to incentive the diversification of the uses of the territory, such as food production. SEA also suggests the adoption of incentive programs to establish multiple-use forests. The SEA recommended that the state government integrate its program for strengthening family agriculture with land-use planning criteria, based on cooperative systems The methodology employed has evidences to be replicable in other regions of Brazil and in developing countries.