基于RS和GIS苏州市近20年来城镇扩展对土壤资源的影响研究

随着城市化的加速发展,越来越多的土壤资源被侵占。本文借助RS和GIS技术,利用1984、1995、2000、2003年4期TM卫星遥感影像,采用多时相连续对比法对苏州市近20年来城镇扩展情况进行了分析;结合苏州市土壤图和全国第二次土壤普查数据,对苏州市近20年来城镇扩展占用土壤资源的情况进行了研究;并初步提出城镇扩展对粮食安全的影响。     

基于嵌套子集方法对南京市城镇化用地时空变化分析

随着城镇化的加速发展,越来越多的土地资源被占用。本文应用嵌套子集方法,并借助RS和GIS技术,利用1984、1995、2000、2003年4期TM卫星遥感影像,对南京市近20年来城镇扩展情况进行了分析。结果表明:1984─2003年间,随着城市化水平的不断提高,南京市城镇用地面积不断扩大,填充度从1984年的3.5%提高到2003年的7.2%,增加1倍多,并呈嵌套格局,且嵌套程度越来越高;各乡镇填充度的变化表现出差异性,即市区的乡镇、市区周边的乡镇以及在区县的乡镇的填充度增加较大,其他大部分乡镇的填充度虽然都有不同程度的增加,但增加程度不大,还有一些乡镇的填充度没有变化。     

近20年来南通市区城镇用地扩展遥感监测

借助RS和G IS技术,利用TM卫星影像资料对近20年来南通市区城镇用地扩展过程进行了研究。结果表明,1984~2003年主城区扩展趋于缓慢,市区边缘带乡镇扩展速度加快。在扩展模式上,主城区先是沿着老城区填充式零星的扩展,然后逐步与周边乡镇连成一片,并形成新的扩展中心。城镇用地扩展的主要驱动力是工业化水平的提高。把市区城镇用地扩展图与土壤图相叠加,并参照1987年土地利用现状调查资料,结果表明南通市区城镇用地扩展主要侵占城市周边优质的菜地和农田。     

城市扩展区土壤保护效益分析-以沈阳浑南新区为例

土壤是地表植物生长存续的基本条件。随着城区的不断扩大，乡村土地不断转化为城镇土地，避免城区建设过程中破坏原有土层，保护土壤资源，具有很好的经济和生态环境效益。我国城市化进程将长期持续发展，城区面积不断扩大，如果能制定相关法律法规，采取严格的保护措施．可以在城区扩展过程中保存大量的土壤资源。     

城市化对郑州市土壤功能演变的影响

城市化快速发展不仅造成了自然土壤面积和类型的缩减，也导致土壤功能发生变化并通过土地利用方式的变化表现出来。本文以郑州市为例，通过研究城市扩张和土地利用变化来探讨城市化过程中土壤功能演化特点。研究结果表明：在过去的20年间，随着城市化的发展，土地利用结构发生着剧烈变化，城市建设面积不断扩张，水稻土土类和盐化潮土亚类消失，另外伴随还消失了2个土属和11个土种，一些特定的土壤功能消失；伴随着土地利用变化，土壤主要从生产功能、生态功能向土壤承载功能转换，其次为生态功能向生产功能转化。土壤功能这样的转换不仅增加了区域农业生产压力，也可能对区域生态环境产生不可忽视的影响。     

城市化过程对土壤资源影响研究进展

世界范围内的快速城市化过程对土壤资源的质与量都产生了深刻影响.作为一种不可再生性自然资源,土壤在我国快速城市化过程中的强烈人为活动影响下发生功能上的转化、弱化甚至消失.城市及其周边地区的土壤景观、各种土壤过程都明显异于传统的土壤质量演变规律.与农业生态系统相比,城市生态系统更加复杂,城市化过程中土壤演变研究的挑战性也更大.深入开展城市化过程中土壤质、量响应及其生态环境效应的系统研究意义重大.     

基于RS与GIS唐山市城镇扩展对耕地产能影响的定量评估

分析研究当前区域性耕地资源数量与质量的变化格局和态势,定量评估城镇扩展对耕地产能的影响,具有重要的理论和现实意义。以唐山市1993年和2003年两期Landsat TM/ETM遥感影像为主要数据,运用Erdas软件进行人机交互解译,并借助GIS软件分析城镇扩展对耕地面积和空间分布的影响。基于农用地分等成果为基础,通过典型调查,建立耕地利用等指数和耕地实际产量的回归模型,定量估算10 a间城镇建设用地扩展对耕地产能造成的损失。研究表明10 a来唐山市建设用地总量迅速扩展,主要增加源为耕地,城镇建设用地扩展占用耕地的面积达14.27×103 hm2,主要分布于丰润区和丰南区,即1993－2003年间唐山市城镇发展方向主要为南北双向扩展,该两区产能损失分别占全市总损失产能的41.88%与37.97%,且城镇扩展占用的多是7等以上城镇周边农业基础设施好、生产力水平较高的农田,损失产能达1.35×105 t,对区域农业生产和粮食安全产生了不容忽视的影响。     

城市化过程中耕地土壤资源质量损失评价与分析

该文在遥感和GIS技术支持下,以长时间序列（1996～2006年）的多源SPOT高分辨率影像为主要数据源,在准确获取土地利用变化信息的基础上,利用土壤资源质量指数（SQI）来评价和分析杭州市快速城市化过程中土壤资源质量损失状况。结果表明：10 a间,杭州市快速城市化过程中土壤质量付出的代价是巨大的,城市扩张侵占的都是优质土壤,其中优质黄松土的损失面积占到损失总量的38.11%。土壤资源质量等级最高（Ⅰ）的土壤资源的损失量占到了总量的43%。其中耕地发生质量损失的面积占到损失总量的83.83%,这其中45.86%的损失量都来自土壤资源质量等级最高的耕地资源。城市化过程中土壤资源有效利用与合理保护已成为亟待解决的问题。     

三峡库区耕地城镇化及城镇扩展测度

根据1975、1987、1995、2000和2005年的遥感影像解译出的城镇用地数据,分析了城镇扩展过程中耕地占用的规律,采用城镇用地扩展强度、城镇用地扩展极核、城镇用地扩展类型、城镇用地扩展紧凑度、城镇用地分维数等理论模型从数量上对研究区城镇用地的扩展进行了对比分析,然后采用缓冲区分析从空间上对研究区在不同缓冲区带内的扩展轨迹开展了对比分析。研究结果表明耕地占用较多的是重庆市区、渝北区;受重庆市区和渝北区生长极核的影响,邻近区县的扩展强度比较大;总的来看其扩展平稳有序,属紧凑填充式;缓冲区分析对城镇扩展的轨迹研究是有效的,在研究区的第二缓冲带内的城镇扩展的强度是较大的。对研究区1975～2005年期间城镇用地对耕地占用情况及扩展的空间模式的分析,有利于控制未来城镇化对耕地的占用,把握城市化进程所处的阶段及预测城市的未来发展趋势。     

基于MapXtreme的湖北三峡库区土壤资源信息系统的设计与实现

针对土壤信息数据在农业生产中的重要作用,结合数据库技术、网络技术等,采用MapXtreme作为网络地理信息系统平台,设计了湖北三峡库区土壤资源信息系统,对扩大库区土壤信息数据的共享范围及高效管理土壤资源信息具有重要意义。文章着重介绍了系统的设计思想、体系结构和实现的关键方法,并给出了系统的运行实例。     

Assessing the impact of urban sprawl on soil resources of Nanjing city using satellite images and digital soil databases

The Yangtse delta area is one of the most rapidly developing areas in China. There are mega-cities like Shanghai and Nanjing and the surrounding urban areas of different sizes including those along the lower reach of the Yangtse river from Shanghai to Nanjing. In combination with their satellite counties and towns, they form one of the most densely distributed urban areas in China. This is a case study conducted in Nanjing city to evaluate the impact of urban sprawl on soil resources using satellite images and digital soil database maps. The extent of the developed land in the study area and the impact of development on soil resources at a scale of 1:200,000 are estimated. The soil types occupied by the urbanization process are determined by overlaying the soil map on the satellite images (Landsat TM) of the study area at different times (1984, 1995, 2000 and 2003). This study uses a geographic information system (GIS) to combine urban land use maps of different times derived from satellite images with data on soil characteristics contained in soil databases. The results document the rapid expansion of urbanization in Nanjing city, as well as the soil types occupied by the urbanization process, and their quality. The urban area has increased 43,544 ha, 2 times more than in 1984. The urban area expanded at an annual rate of 6.9%. Thirty of the total 32 soil types (soil families) within the city were utilized by the urbanization process among which Loamy typic-Fe-leachic-stagnic anthrosol ranked the highest (12,007 ha). The loss of surface land to urban use in Nanjing city has ranged from 4.8% in 1984 to 11.8% in 2003. Soils of the first class (5349 ha) and second class (20,781 ha) were 61.5% of the total occupied soil area. Results for Nanjing show that residential, commercial, and industrial development, known as “urban sprawl,” appear to follow soil resources, with the better agricultural soils being the most affected. Several soil types appear to be on the verge of being replaced by urban sprawl. Growing urbanization may threaten food security, soil diversity and sustainability. The extent and geographic distribution of soil quality and the pedodiversity for land presently under urbanization in the study area may be determined through modeling.     

Measurement of urbanization process and the paddy soil loss in Yixing city,China between 1949 and 2000

This study used GIS technology, remote sensing images of 1949, 1966, 1981, 1984, 1988, 1992, 1996 and 2000, to analyze the spatial process of urbanization and its impact on the soil resources in Yixing city, southeast China. The results showed that the urban area grew more than three-fold during 51 years and the loss of paddy soil accounted for 82.9% of all soil loss. According to the expansion dynamics and the results of spatial metrics, the urban expansion process in Yixing could be divided into four steps, the initial step (1949–1966), the almost standstill step (1966–1981), the preparation step (1981–1984) and the rapid growing step (after 1984). The study also indicated that the urban expansion was encouraged by the transportation system, however, restricted by the rivers, lakes and hills. The local government's decision also affected the spatial process of urban expansion. The spatial process of Yixing urban expansion might reflect the spatial process of urbanization of southeast China, the region with a rapidly growing economy.     

基于仙农熵的土壤多样性和土地利用多样性关联评价

以南京市为例,将多样性理论与方法应用于土壤和土地利用相关性评价中,对该市1986年和2003年的遥感数据进行了土地利用分类,计算了各土壤类型和各土地利用类型的构成组分多样性指数以及多网格尺度下的空间分布多样性指数,并提出一种用于评价土壤和土地利用相互关系的关联系数,求算了5 km网格尺度下南京市典型土种单元同9种土地利用类型之间的关联系数。研究结果表明,1986年至2003年这十余年间,南京市土地利用的构成组分变化明显,其中1986年的构成组分多样性为0.361,2003年为0.444。2003年南京市土地利用的空间分布离散性更高,5种主要土地利用类型的空间分布多样性均有明显增加。南京市典型土种与各土地利用类型关联系数的计算结果表明,多组关联系数的变化趋势相同,由此推断相比于1986年,2003年南京市土壤与土地利用之间的相互联系更为复杂多变。     

How does the conversion of land cover to urban use affect net primary productivity? A case study in Shenzhen city, China

China has made great economic achievements since the Reform and Opening policy implementation. Shenzhen as the representative city has experienced rapid urbanization and population growth. Urbanization strongly changes the nature of the land surface and has a large influence on the regional ecosystems. In the process of urbanization, fertile cropland and original forest are often destroyed. It is important to regularly monitor the effect of urbanization on the natural environment so as to allow us to control the encroachment to a reasonable extent. Net primary productivity (NPP) is an important productivity indicator of the ecosystem. We obtained land covers from Landsat TM images to quantify urbanization of Shenzhen between 1999 and 2005. We used the Moderate Resolution Imaging Spectroradiometer (MODIS-based) Normalized Difference Vegetation Index (NDVI) data, Landsat-based land cover map, meteorological data and other field data to drive the CASA productivity model and obtain net primary productivity for the study area. Finally, we estimated the effect of urban sprawl on regional NPP. The study on Landsat-based land cover maps indicated that a move towards urban is the most significant landscape change in Shenzhen City and urbanization has irreversibly transformed about 20.21% of Shenzhen's surface during 1999–2005. NPP loss mainly resulted from urbanization during 1999–2005 and totaled to 321.51 Gg of carbon, an average annual reduction of 45.93 Gg of carbon. For every square km of Shenzhen area, NPP was on average reduced by 0.0017 Gg of carbon during 1999–2005. The loss of NPP is equivalent to a reduction in absorption of 520.85 Gg CO₂ and release of 385.81 Gg O₂, so urbanization has a large influence on the regional net primary productivity.