广东省耕地资源问题及其对策

通过大量的数字和事实,分析说明广东耕地资源存在的问题：耕地不断减少,人口迅速增加,人多地少的矛盾尖锐;耕地消耗过多,１９８０￣１９９５年平均每年减少２．８９×１０＾４ｈｍ＾２,耕地闲置浪费现象严重;耕地质量下降,水田有机质含量下降０．１６％,中低产耕地约占２／３;农田环境污染严重,受工业三废污染农田达１０．４７×１０＾４ｈｍ＾２;耕地后备资源紧缺。提出的主要对策是节流、保护、挖潜,强化耕地资源保护     

利奥波德的土地伦理观及其生态环境学意义

利奥波德土地伦理思想的主要贡献在于:1)提出了土地共同体概念并把伦理范畴扩展到人与土地共同体之间的关系,其目的是建立一种正确的人与土地的关系,即人与自然之间的和谐关系;2)构想了“生物区系金字塔”理论模型,借用生态学范畴(如“能量流”和“食物链”等)来说明自然体系的复杂性及运行机理。土地伦理观以生态学视角重新审视自然有机体,深化了人类对环境的认识并推进了美国和世界的环保实践。通过引证和逻辑分析方法,在概要介绍土地伦理思想内容的基础上对其生态环境学意义提出新的认识。     

中国城市空间拓展与经济增长关系研究——以261个地级市为例

近年来,随着中国城市化进程不断加快,各地普遍出现了以低价出让农业用地,盲目投资房地产及城市基础设施,大规模兴建新城区为主要特征的城市蔓延现象。造成这种城市建成区低密度无序扩张的原因,除了不规范的城市用地转化机制外,很大程度上是源于对城市化与经济发展关系的不当认识。以全国261个地级市为例,基于1990~2010年城市社会经济发展数据,采用多元回归模型客观分析了中国城市土地蔓延与经济增长的关系。研究结果表明,在控制住城市固定资产投资、外商投资（FDI）、房地产泡沫效应等因素后,城市现有建成区面积及其扩展幅度与其人均国民生产总值并没有显著相关关系。也就是说,单纯追求城市建成区规模扩张并不能直接促进城市经济发展。     

Permafrost mapping of Northeast European Russia based on the period of climatic warming 1970-1995

Verdenskrigen som efterhånden i do krigførende land tok alle hjelpemidler og all intelligens i sin tjeneste og innskrenket den frie samferdsel selv for de nøitrale stater, måtte selvfølgelig legge hindringer i veien for forskningsekspedisjoner til Asia. De stoppet velikke helt op. Som vi skal se blev der også under krigen foretatt og begynt undersøkelser av denne art; men først efter krigen utviklet de sig igjen i større stil. Det synes derfor å være naturlig å velge denne verdenskatastrofe som et skille, og jeg vil i det følgende mere utførlig omtale bare de ekspedisjoner og forskninger, som vesentlig er blitt utført efter denne tid.     

Avgrensningsproblem Og Gymnasial Undervisningsteknikk I Økonomisk Geografi

Et karakteristisk trekk ved geografiens utvikling i den siste menneskealder er at de geografiske særdisipliner mere og mere krever en selvstendig stilling. Men denne frigjøringsprosess vekker strid. Særlig gjelder dette for den økonomiske geografi (erhvervsgeografien). Grunnen til at denne del av geografien har sprengt så sterkt på, er at den økonomiske utviklingsprosess er blitt en stadig mere og mere dominerende faktor i vårt samfundsliv. Men den viktigste årsak til at erhvervsgeografiens frigjøring skapte slik spenning, var at den økonomiske geografien i altfor høi grad vilde komme til å sprenge geografiens gamle grenser.     

卧龙自然保护区土地利用变化对土壤性质的影响

森林景观受干扰后的次生演替、人工林种植与农业耕作等在许多方面影响着土壤性质的变化。研究选取了四川卧龙自然保护区作为研究地点 ,阐述湿润高山区的土地利用方式与土壤性质之间的关系。选择了六种典型的土地利用方式加以比较 ,方差分析结果表明 ,不同土地利用之间土壤容重、全氮、有机碳、速效磷、速效钾的含量差异显著。相比之下 ,农田土壤养分含量偏低 ,而灌丛有着较高的有机碳、总氮与有效氮含量。 0～ 4 0cm土壤碳的储量变化幅度不大。综合土壤退化指数表明 ,坡耕地 ,撂荒地与人工林有土壤退化的趋势 ,而灌丛与次生林对土壤的性质有着改善的作用。人工林年龄与土壤有机碳、有机氮的含量正相关。     

Soil and plant responses to degradation of alpine grassland in source region of the Yellow River

Land degradation has been rapidly taking place in source region of the Yellow River in China. This study was conducted during 2008 in Maduo County to investigate soil and plant changes in relation to land degradation. Several results were derived from this work. First, the soil organic carbon (SOC) and total nitrogen (TN) decreased significantly on the extremely degraded land comparing with the natural grassland. Second, soil bulk density increased as land degradation worsened. Soil bulk density of the extremely degraded land was significantly greater than that of the grassland. Third, pH showed no obvious variation pattern. Finally, aboveground biomass decreased from grassland to the moderately degraded land. But aboveground biomass increased on the extremely degraded land and very extremely degraded land with most aboveground biomass inedible for livestock.     

环渤海地区土地利用变化的驱动力分析

1985到1995年间,环渤海地区占总面积30%的土地发生了利用方式的变化,耕地变化是其核心类型。耕地变化的主要流向依次为农村居住用地、林草地、城市居住建设用地以及果园和水域。本文通过对耕地流向及其与人口变化、农业经济发展的关系等进行分析,确认土地管理政策、人均居住用地的增长、农业生产结构调整以及城市扩张是该区土地利用变化的主要驱动因素     

Monitoring land use change in an African tribal village on the rural-urban fringe

Urban land uses commonly compete favourably with rural land uses on the rural-urban fringe under the principal of land rents in a free market. Where a free market does not exist, complications in land use competition may develop and make it difficult to acquire land for the ever increasing demands of urban use. This study uses GIS to quantify and analyse patterns of land use change reflecting competition among various types of land use in the village of Tlokweng on the rural-urban fringe of the city of Gaborone, Botswana, over a 26-year period between 1963 and 1989. The villages in the tribal territories on the rural-urban fringe where Tlokweng is located practise communal land tenure under which individuals are allocated land parcels free of monetary cost. The city of Gaborone, on the other hand, has a free land market. Differences in the price of land have encouraged migrants to the city to attempt to acquire residential plots from the tribal territories on the city's rural-urban fringe. However, since there are no incentives for exchanging land, would-be purchasers have faced resistance in acquiring plots on the outskirts of the village. During the period of study there was no organized expansion of the village and patterns of land use change could only be analysed by monitoring the increase in the number of plots allocated to various uses and the aggregate area occupied by these plots. Results indicate that more and more allocations of residential plots are made from vacant land within the older part of the village, resulting in increased congestion. It is recommended that commercialization of the communal lands, already contemplated by the government, may partially reduce resistance to changes in land ownership and arrest further congestion in the villages on Gaborone's rural-urban fringe.     

基于农用地价格体系的征用地价应用研究

农用地价格体系和估价成果应用是当前农用地定级估价工作的难点和争论焦点，该文提出了农用地价格体系应以资源基准地价为基础，通过一系列修正，得出分级分区的征用基准地价、不转变用途的农地流转价、转变用途的农地转用价；以佛山市南海区的农用地估价成果为例，就其与现行征地补偿标准进行了比较，并与南海城区、广州市区城镇建设用地基准地价的相互衔接性进行了验算，应用成本逆推法，从城镇基准地价导出建设用地生地地价，在内涵一致的条件下相互比较。结果表明，按此地价体系建立的农用地征用价能够与城镇地价相衔接，可为城乡地价一体化的建立提供实证。     

广州市土地利用结构优化配置及其潜力

基于广州市土地利用结构、地区经济、生态与社会特点,结合广州城市总体规划(2010-2020),对广州市域土地利用结构进行生态经济效益-自然生态效益导向的多目标优化配置研究。结果表明：对广州市土地利用数量结构进行调整,一定时间内能够满足地区可持续发展;但是,土地仍然承担着巨大的压力,焦点是建设用地和农用地之间的数量转变,以耕地为主,也包括对未利用土地的利用;土地利用潜力度模型结果显示,通过优化土地利用结构,土地系统的协调度增大而潜力度减小：在生态经济效益目标下,潜力度分别为0.628～0.661,0.372～0.339;在自然生态效益目标下,分别为0.531～0.782,0.469～0.218,表明土地利用系统将趋于更高的协调状态,而其数量结构优化配置的潜力减小,优化各产业部门内部土地资源结构及其空间布局,将是广州市土地资源高效集约利用和进一步挖潜的主导方向。     

Changes in arable land in response to township urbanization in a Chinese low hilly region: Scale effects and spatial interactions

Rapid urbanization leads to losses in arable land; quantitatively analyzing the impact of urbanization on arable land is significant for arable land management. However, changes in arable land due to urbanization with scale and neighborhood effects remains poorly understood at the town scale. In this study, high-resolution historical land use data, landscape metric analysis and spatial regression were integrated to quantify the impacts of urbanization on arable land use change (abandonment and conversion) at spatial scales of 300 m–3300 m using a block size increment of 200 m and at the catchment scale in the town of Jinjing in subtropical central China. Arable land abandonment was the predominant type of arable land change and presented strong spatial autocorrelations at each spatial scale. Arable land was converted to tea fields because agricultural structure transformations were occurring around the urban cores, and the amount of arable land converted to residential land accounted for only a small proportion of the total arable land loss and had no spatial autocorrelation. The significance and robustness of the arable land changes impacted by urbanization had obvious scale effects and strong neighborhood effects in nearby regions. Compared with block scales, the catchment scale is an optimal scale for assessing the influence of urbanization and applying planning policy. Our results highlight the significance of incorporating spatial interactions in urbanization research, which can generate less biased estimations and consequently lead to proper policy implication and recommendations. In addition, multi-scale comparisons are helpful for better understanding the relationships between arable land changes and urbanization and provide further insights into the harmonious development of rural settlements and urban cores to preserve arable land.     

Temporal and Spatial Characteristics and Optimization of the Intensive Use of Cultivated Land in Maoming City

Improving the level of intensive cultivated land use is an important measure to ensure food security and promote the sustainable development of the regional society and economy. Based on data from the statistical yearbook of Maoming City and its counties and districts from 2005 to 2018 and the land use change database of Maoming City for 2018, this study constructed an evaluation index system for four aspects: cultivated land use intensity, cultivated land use degree, cultivated land output benefit and cultivated land sustainable use status. The level of intensive use of cultivated land in Maoming City from 2004 to 2017 was evaluated by AHP, the range method and the comprehensive evaluation model, and its temporal and spatial characteristics were evaluated. The results revealed three major points. (1) The intensive use of cultivated land in Maoming City in the past 14 years was good, and its level showed an overall upward trend, with the intensive use degree of cultivated land rising from 0.4045 in 2004 to 1.3148 in 2017. (2) The levels of intensive use of cultivated land in each county and district of Maoming City were generally on the rise, with no significant differences between them. However, according to the regional distribution, the intensive use level of cultivated land was highest in Maonan District, while it was relatively low in Dianbai County. The largest increase in the level of cultivated land intensive use was in Gaozhou, and the smallest was in Dianbai County. (3) According to the existing problems of cultivated land utilization in Maoming City, combined with the current international and domestic measures to effectively improve the level of intensive use of cultivated land, four suggestions are put forward: to improve the efficiency of cultivated land utilization and effectively protect basic farmland; to improve the overall urban planning and rationally adjust the layout of construction land; to raise farmers’ awareness of the intensive use of cultivated land; and to increase agricultural investment and improve agricultural infrastructure.     

唐山市中心区土地利用潜力评价研究

以唐山市中心区土地利用为例,在分析研究区土地利用现状的基础上,综合研究影响城市土地利用潜力的因素,设计了评价流程,构建了土地利用潜力评价的指标体系和评价模型。结果显示,中心区总面积11 479.27hm2,其中无容量土地、容量完全损失土地、未利用的土地、低度利用的土地、合理利用的土地、过度利用的土地6种潜力类型的土地面积分别占总面积的27.86%,6.43%,5.69%,23.64%,28.62%,7.76%,土地利用率偏低,有很大的挖潜空间。通过对唐山市中心区城市土地利用潜力的评价,不仅为中心区的城市建设和土地利用提供依据,也为城市土地利用潜力评价的推广和应用提供方法和思路。     

SELLERS AND NONSELLERS OF LAND FOR NEW RURAL HOUSING*

Landowners can choose either to sell or to hold their land in areas with active rural land markets. Sellers and nonsellers are both important because their decisions shape patterns of land use. Analysis of mail survey data from 286 landowners in the Rochester, MN SMSA isolates four characteristics that distinguish sellers from nonsellers: occupation, size of landholding, recent acquisition of land, and interest in selling land. Nonsellers are often farmers with a large landholding and no interest in selling. More information is needed about their non-economic motives for holding land.     

吉林西部土地荒漠化预测研究--以吉林省镇赉县为研究区

以吉林西部土地荒漠化典型区之一的镇赉县为研究对象，在GIS的支持下，根据研究区两个时期的遥感影象，解译出土地利用图和荒漠化土地分布图，通过叠加处理把荒漠化土地作为单独地类从其他土地利用类型中剔除，得到两期包括荒漠化地类的土地利用类型图，进一步叠加，得到监测期内镇赉县荒漠化土地相对于其他土地利用类型的时空变化。介绍了马尔柯夫荒漠化预测模型的建立过程，并应用马尔柯夫模型预测和分析了镇赉县土地荒漠化的演化趋势，结果表明：如不采取有效措施，镇赉县荒漠化将继续发展，荒漠化土地将逐步蚕食掉现有的草地、林地和耕地，2050年，荒漠化土地将占研究区的32．49％。     

北京市城区扩展的空间格局与影响因素

2000年以来北京市持续推进产业结构升级,由此引发了经济活动的空间重构,伴随着住宅郊区化、职住分离以及交通基础设施的配套建设,将引起新一轮城市空间扩展。构建顾及综合可达性因素、邻域因素、自然因素、规划因素以及社会经济因素的城市空间扩展模型,分析诊断北京城区扩展进程中的主要影响因素及问题,从而为指导与管治北京市城市空间的有序扩展提供科学支撑。研究表明：① 综合交通静态可达性（单一年份）与城市扩展呈显著负相关;综合交通动态可达性（年份之间的可达性变化）则在引导北京市城市空间发展方面并无显著影响。② 邻域建设用地百分比与城市扩展呈正相关,而农用地、林业用地及水域用地的比例将减少土地开发的概率。③ 城市总体规划在指导城市空间扩展的纲领性地位逐渐受到重视,其对城区扩展的影响程度最为显著。④ 常住人口的分布现状、第二产业企业数量、第三产业企业数量分布现状对土地开发无显著影响。⑤ 认为北京市静态可达性与土地利用变化呈负相关,即可达性条件较差的地区,土地开发的可能性越小,这与北京市“摊大饼式”空间蔓延和居住郊区化的发展现实相符;北京市动态可达性与土地利用变化亦呈负相关,表明可达性提高程度越大的区域并不一定带来更高的土地开发几率,这从侧面传递了沿着既有建成区进行土地扩展的概率远远大于由于诸如轨道交通建设而带来可达性极大改善区域的概率。因此,重视与发挥综合交通动态可达性指标对城市扩展的引导作用,将是有效破解城市蔓延式扩张、优化城市扩展的重要手段。     

Large-scale land cover mapping with the integration of multi-source information based on the Dempster–Shafer theory

Land cover type is a crucial parameter that is required for various land surface models that simulate water and carbon cycles, ecosystem dynamics, and climate change. Many land use/land cover maps used in recent years have been derived from field investigations and remote-sensing observations. However, no land cover map that is derived from a single source (such as satellite observation) properly meets the needs of land surface simulation in China. This article presents a decision-fuse method to produce a higher-accuracy land cover map by combining multi-source local data based on the Dempster–Shafer (D–S) evidence theory. A practical evidence generation scheme was used to integrate multi-source land cover classification information. The basic probability values of the input data were obtained from literature reviews and expert knowledge. A Multi-source Integrated Chinese Land Cover (MICLCover) map was generated by combining multi-source land cover/land use classification maps including a 1:1,000,000 vegetation map, a 1:100,000 land use map for the year 2000, a 1:1,000,000 swamp-wetland map, a glacier map, and a Moderate-Resolution Imaging Spectroradiometer land cover map for China in 2001 (MODIS2001). The merit of this new map is that it uses a common classification system (the International Geosphere-Biosphere Programme (IGBP) land cover classification system), and it has a unified 1 km resolution. The accuracy of the new map was validated by a hybrid procedure. The validation results show great improvement in accuracy for the MICLCover map. The local-scale visual comparison validations for three regions show that the MICLCover map provides more spatial details on land cover at the local scale compared with other popular land cover products. The improvement in accuracy is true for all classes but particularly for cropland, urban, glacier, wetland, and water body classes. Validation by comparison with the China Forestry Scientific Data Center (CFSDC)–Forest Inventory Data (FID) data shows that overall forest accuracies in five provinces increased to between 42.19% and 88.65% for our MICLCover map, while those of the MODIS2001 map increased between 27.77% and 77.89%. The validation all over China shows that the overall accuracy of the MICLCover map is 71%, which is higher than the accuracies of other land cover maps. This map therefore can be used as an important input for land surface models of China. It has the potential to improve the modeling accuracy of land surface processes as well as to support other aspects of scientific land surface investigations in China.     

盐城开发空间区划及其思考

在国家“十一五”规划纲要中, 将国土空间划分为优化开发、重点开发、限制开发和禁止开发四类主体功能区, 这是新时期传统区划理论和方法为国民经济和社会发展服务的一次重要创新。作者认为: 主体功能区划主要在于解决区域问题, 用科学发展观协调区域发展。 因此, 功能区区划的理论和方法也需要与时俱进的创新。文章通过盐城沿海开发空间区划实例进行功能区区划的理论和方法探索。首先, 综合经济区划。运用传统的综合经济区划理论与方法进行经济区划分, 大致确定不同经济区的经济发展布局方向; 其次, 控制开发区划。 综合考虑上述综合经济区的功能, 景观生态体系建设需要, 土地利用现状、辐射沙洲分布、近海海域污染、海港分布、水源保护地以及自然保护区和生态保护区等, 确定相关的禁止开 发区和限制开发区; 第三, 开发潜力区划。以乡镇为基本单元, 运用多因子分析方法, 按照资源环境承载力、现有开发密度强度、未来发展潜力3 个主因子进行开发潜力区划; 最后, 在上述三个区划的基础上, 进行主体功能区划。文章也认为: 主体功能区实质是一种区域发展政策区, 其区划也只是一种纯粹的区域划分, 是目前经济社会发展规划、土地利用规划和城市总体规划“三规”分立走向“三规”合一的空间平台。     

SELLERS AND NONSELLERS OF LAND FOR NEW RURAL HOUSING∗

Landowners can choose either to sell or to hold their land in areas with active rural land markets. Sellers and nonsellers are both important because their decisions shape patterns of land use. Analysis of mail survey data from 286 landowners in the Rochester, MN SMSA isolates four characteristics that distinguish sellers from nonsellers: occupation, size of landholding, recent acquisition of land, and interest in selling land. Nonsellers are often farmers with a large landholding and no interest in selling. More information is needed about their non-economic motives for holding land.