长株潭城市群农业用地损失的动态模拟研究

对城市群发展过程中的农业用地损失进行动态模拟研究,有助于准确归纳其损失的趋势和机制,为农业用地保护规划的制定提供依据。以长株潭城市群为例,通过遥感影像图的收集与处理以及空间数据库、方格网系统、十二向玫瑰图和三维山丘图的构建,对城市群扩张和农业用地损失的过程进行动态模拟,通过离心模型归纳导致农业用地损失的动力机制,并对2020、2025年的农业用地损失情况进行预测。结果显示:城镇建成区扩张是长株潭城市群农业用地损失最主要的原因。伴随着城市群空间结构的演变,农业用地损失经历了"中心区主导—中心区与产业园区共同主导—连绵式损失"的过程。如不加以控制,至2025年,一个总面积达1 500 km~2,呈连绵状分布的超大型都市区将在长株潭城市群形成,现有中心城区、产业园区之间的农业用地将逐渐消失殆尽,从而造成难以弥补的环境损失。从空间规划上优化城市群的空间结构和发展方式,从政策法规上对侵占行为进行严格控制,是保护农业用地的关键所在。研究有望为我国城市群环境保护规划的制定提供方法论参考。

Dynamic Simulation Analysis on the Loss of Agricultural Land of Changsha Zhuzhou Xiangtan Urban Agglomeration

To conduct a dynamic simulation analysis on the loss of agricultural land in the process of urban agglomeration development is conducive to summarize the trend and mechanism of the agricultural land loss accurately, and provide basis for the formulation of agricultural land conservation planning. Taking Changsha, Zhuzhou,Xiangtan urban agglomeration as an example, through the collection and processing of remote sensing images and the establishment of spatial database, the grid system, the 12 directions rose map and the 3D hill diagram, this paper conducted a dynamic simulation analysis on the processes of the expansion of urban agglomeration and the loss of agricultural land. Through the centrifugal model, the driving mechanism of the loss of agricultural land was concluded. Then we carried out a prediction on the loss of agricultural land in 2020 and 2025. The results show that: the expansion of urban built up area is the main reason of the loss of agricultural land in Changsha, Zhuzhou, Xiangtan urban agglomeration. Along with the evolution of urban agglomeration spatial structure, the loss of agricultural land has experienced a process of Centers Leading Centers and Industrial Parks Co leading Continuous Loss. If not effectively controlled, until 2025, a continuously distributed mega metropolitan area with acreage of 1 500 km2 will form. Meanwhile, the agricultural land between existing urban centers and industrial parks will gradually disappear, resulting in irreparable environmental damage. The key of agricultural land protection includes two aspects: on the one hand, the spatial structure and development mode of urban agglomeration should be optimized by spatial planning, on the other hand, the occupation should be controlled strictly in terms of policies and regulations. The research of this paper could provide a methodological reference for the formulation of environmental protection planning for the urban agglomerations in China.