Spatial layout optimization of urban space and agricultural space based on spatial decision-making

Abstract: The scientific delineation of urban space and agricultural production space restriction boundaries is an important measure for the development of city and food security. The urban growth boundary needs to be set to control the urban space sprawl. The farmland accounted for a large proportion of agricultural production space, the prime farmland protection boundary is established to protect the agricultural space. In the year of 2014, the Yingtan City was chosen by the Chinese government as the pilot city to lunch the multi-plan integration project, this project makes the Yingtan City become a perfect place to analyze the reasons that cause the spatial layout contradictions between the urban space and agricultural space, and to seek measures to solve the spatial layout contradictions. In this paper, we took the central district in Yingtan City as an example, and built the layout optimization of urban space and agricultural production space on the basis of construction suitability evaluation and comprehensive farmland quality evaluation on the GIS platform. Through the correction form the city development direction prediction, new construction land scale, the prime farmland protection scale, and farmland utility grade, the preliminary scheme of urban growth boundary and prime farmland protection boundary were generated. The overlay analysis process was applied on the GIS platform to diagnose the contradiction area between the preliminary schemes of urban growth boundary and the prime farmland protection boundary. The urban growth boundary and the prime farmland protection boundary were optimized based on the contradiction coordination principle through spatial decision-making process. The base of spatial contradiction coordination was to make the urban growth boundary and the prime farmland protection boundary of the equal importance. The results showed: (1) the construction suitability evaluation score from high to low presented the circle type of spatial distribution, the plots which had comprehensive farmland evaluation scores were distributed in the east and west part of the central district; (2) based on the analysis of construction land weight transfer, convex hull analysis of urban expansion type, and the infrastructure and industrial zone layout analysis, the north part of the central district was the future city development main direction; and (3) the preliminary scheme of prime farmland protection boundary was divided into adjustable area and regulation area based on the farmland natural utility grade. The farmland plot with lower natural utility grade than the average farmland utility grade in the research area was divided into the adjustable area. The farmland plot with higher natural utility grade than the average farmland utility grade in the research area was divided into the regulation area. The spatial decision to deal with the contradiction between the urban growth boundary preliminary scheme and the regulation area was to adjust the urban growth boundary preliminary scheme to ensure the farmland protection. The spatial decision to deal with the contradiction between the urban growth boundary preliminary scheme and the adjustable area was to adjust the prime farmland protection boundary preliminary scheme to ensure the urban development. From the research, we concluded that the spatial decision-making process could make the delineation of the urban growth boundary and the prime farmland protection boundary more objective and scientific.