基于空间集聚格局和边界修正的基本农田保护区划定方法

划定优质高产、连片闭合、空间连续、边界清晰的基本农田保护区,使土地利用总体规划中的基本农田保护区由"地块空间组合"回归其"分区"的科学本质,形成具有空间调控与引导作用的闭合区域,对促进耕地保护具有重要意义。该文以北京市平谷区为例,在从自然质量、区位条件、发展稳定性和生态安全性4个方面评价基本农田综合质量的基础上,采用局部Moran's I指数确定优质基本农田空间集聚格局,进而利用缓冲区分析提取线状地物确定基本农田保护区边界,划定具有空间调控与引导功能的基本农田保护区。研究结果表明：1）平谷区基本农田综合质量指数平均为53.66,综合质量整体较优。2）基本农田高高集聚区（H-H）和低高集聚区（L-H）形成基本农田保护重点区域11 568.93 hm2;3）经边界修正后,平谷区共划定基本农田保护区44个,面积共13 395.99 hm2,涵盖基本农田比例约80%;相比原方案,新划定基本农田保护区在空间连片度、边界规整度及用途均质度等方面均得到优化。未来应加强保护区内基本农田质量建设,加快区内非农地类退出,进行基本农田保护区边界建设,实施基本农田园区式管理。基于空间集聚格局与边界修正的基本农田保护区划定方法可为基本农田集中连片保护提供有益参考。

Approach of land use zone for capital farmland protection based on spatial agglomeration pattern and boundaries modification

Abstract: Current studies are focused on the high quality farmland parcels identification and aggregation, yet have not considered the concentered and contiguous pattern required in management. As a result, the protected areas of farmland are fragmental in spatial distribution, which increases the difficulty in large-scale production and the risk of occupation by constructive land around. So the capital farmland protection zones need to be transformed from parcels preservation to land use zones in concept; and the zones, which are high-quality and concentrated and have clear outlines and the functions of guiding and separating farmland from constructive and ecological land, can contribute to the capital farmland conservation practice. This paper interprets that land use zone for capital farmland protection has 3 basic rules in zoning. Firstly, the farmland parcels should be almost high-quality with sound drain and irrigation facilities and good capacity to resist the disaster; secondly, zones should have coherence and be closed; and at last, zones should have explicit and unaffected boundary and be encircled by linear features like high-grade road and river, so that they can be convenient for management as the parks. Based on the principles above, this paper proposes the methods consisting of farmland comprehensive quality evaluation, spatial agglomeration of local Moran's I and buffer analysis to delimitate the protected areas of basic farmland, and takes Pinggu District, Beijing City as the case study. At first, it analyzes the comprehensive quality of the capital farmland by multi-factor evaluation and gradual modification method; the factors that are related with the natural quality, location accessibility, development stability and ecological security of the capital farmland are considered in evaluation, and the high-quality capital farmland plot are selected. Then based on the scores of farmland comprehensive quality, spatial agglomeration method of local Moran's I is used to define the spatial pattern of high-quality and low-quality farmland, and the key protection areas of capital farmland are preliminarily delimitated. At last, for the capital farmland protection zones, boundaries modified methods in buffer analysis are used in modification of key areas. Results show that, the average score of the comprehensive quality of the capital farmland in Pinggu district is 53.66, indicating the capital farmland quality is relatively fine. And based on the Moran's I and the local indicators of spatial association method, 4 spatial agglomeration patterns of the fine capital farmland and the other land are obtained, which are high-high, high-low, low-high and low-low pattern, and the high-high and low-high pattern are chosen to the key protection zones that are 11 568.93 hm2. And the final capital farmland protection zones are designed by linear elements such as roads and rivers adjacent to the key protection zones. There are 44 capital farmland protection zones in Pinggu District with the total area of 13 395.99 hm2, covering 80% of the capital farmland plots. The results indicate that the design approach of the capital farmland protection zones based on spatial agglomeration pattern is useful to form the high-quality and concentrated zone with clear outline, which can provide guidelines for the capital farmland protection planning and land use planning in practice.