基于RS与GIS唐山市城镇扩展对耕地产能影响的定量评估

Quantitative assessment of urban expansion impact on comprehensive productivity of cultivated land in Tangshan city based on RS and GIS

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10a间城镇建设用地扩展对耕地产能造成的损失。研究表明10a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14.27×103hm2,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1.35×105t,对区域农业生产和粮食安全产生了不容忽视的影响。

It is of great significance to research the changing patterns of current regional cultivated land and to explore its impact on grain productivity.With the assistance of Erdas software,the actual land use map and statistics data of Tangshan,the maps about the urban land expansion distribution in Tangshan were acquired by interpreting LANDSAT and TM/ETM images of 1993 and 2003 with the aid of the technology of RS and GIS.Method of man-machine interactive operation was applied to interpret LANDSAT and TM/ETM images of 1993 and 2003. Meanwhile, according to the database of soil attributes and spatial parameters in classification and gradation for farming land in Tangshan, the correlation relationship between the land utilization index and the realistic productivity was established. The loss of cultivated land and comprehensive productivity caused by the urban expansion from 1993 to 2003 was studied and analyzed by methods of the statistical analysis and the spatial analysis The results indicated that the cultivated land resource in Tangshan was occupied 14.27 ~ 103 hnl2 in the urbanization expansion during the past ten years. Especially, the cultivated land with high productivity and favorable facilities in the suburbs was decreasing much faster because of their close contiguity to the expanding city, and the total loss of the capacity of cultivated land caused by land shrinkage reached 135thousand tons. Finally, it might be concluded that rapid urbanization was posing an increasing pressure on land resources, of which the impact on regional agricultural production and food security allowed no neglect.