基于"三线"统筹的省域永久基本农田布局优化规则与实证研究

统筹永久基本农田保护红线、生态保护红线、城镇开发边界来优化永久基本农田空间布局能够更好地保住优质耕地资源、保障国家粮食安全。该研究应用文献研究法和归纳总结法，系统梳理了永久基本农田保护红线、生态保护红线 、城镇开发边界（以下简称"三线"）划定的政策法规，建立了"三线"统筹下的省域永久基本农田布局优化规则，并以广西壮族自治区为例进行了验证。结果表明：1）选择耕地国家利用等和集中连片程度进行了永久基本农田"三线"统筹划定，退出了生态保护红线核心区内所有永久基本农田7 413.46 hm2，并将5 073.05 hm2优质连片的永久基本农田以"开天窗"的形式保留在了生态保护红线一般区和城镇开发边界内；2）广西全区退出永久基本农田1 426 540.77 hm2，主要是标注为工程恢复和未标注的非耕地，补划了永久基本农田525 614.37 hm2，主要是生态保护红线和城镇开发边界外优质连片的耕地，布局优化后的永久基本农田保护率高达85.62%；3）布局优化后的永久基本农田全为耕地且与生态保护红线、城镇开发边界之间无交叉重叠，集中连片的永久基本农田达到95.08%，无重度和极重度污染损毁、石漠化和25°以上坡耕地，永久基本农田国家利用等提高了0.06等。建立的永久基本农田布局优化规则实现了"保护优先、布局优化、优近劣出、质量提升、三线统筹"的目标，能够为各省份指导市县统筹三条控制线划定永久基本农田保护红线提供思路借鉴。

Optimizing rules and empirical research of provincial permanent basic farmland layout based on the "Three-line" coordination

Spatial layout of permanent basic farmland can greatly contribute to better preserve high-quality farmland resources, further optimize the spatial pattern of the country for national food security. It is necessary to coordinate the red line of ecological protection and the boundary of urban development. However, there were unclear boundaries of departmental space management authority and low efficiency of resource space management and control, due mainly to the inconsistent delineation time of "three lines", technical standards, coordination of delineation, and the overlaps of delineated space. In this review, the policy and regulations were systematically sorted out using the protection red line of permanent basic farmland, the ecological protection red line, and the urban development boundary (hereinafter referred to as the "three lines"). Some indicators were selected from the current planning, pollution damage, ecological conditions, utilization status, and comprehensive quality. Some rules were established to optimize the layout of permanent basic farmland in the province under the "three lines" coordination. An example was also selected to verify in the Guangxi Zhuang Autonomous Region. The results show that: 1) The overall planning was made for the "three lines" of permanent basic farmland, according to the national utilization of arable land, as well as the degree of concentration and contiguous areas. All 7 413.46 hm2 of permanent basic farmland was withdrawn in the core area of ecological protection red line, and 5 073.05 hm2 high-quality contiguous permanent basic farmland was retained in the form of "skylights" within the general area of the ecological protection red line and the urban development boundary. 2) The whole study area withdrew 1 426 540.77 hm2 of permanent basic farmland, where non-arable land was mainly marked as engineering restoration and unmarked. Specifically, the compensation of 525 614.37 hm2 of permanent basic farmland was located mainly in the high-quality contiguous arable land outside the red line of ecological protection and urban development boundaries. The protection rate of permanent basic farmland was as high as 85.62% after the layout optimization. 3) All concentrated and contiguous permanent basic farmland reached 95.08%, indicating no severe damage, rocky desertification, and sloping land above 25°. The utility grade of permanent basic farmland increased by 0.06. There was also no overlap between the permanent basic farmland and the ecological protection red line, as well as the urban development boundary. Consequently, the established rules were achieved to optimize the layout of permanent basic farmland for the goal of "protection priority, layout optimization, quality improvement, and three-line coordination". This review can also be conducive to coordinating the contradiction between food security, ecological security, and economic development in the province. The finding can provide a sound reference for the cities and counties in provinces, further delineating the protection red lines of permanent basic farmland under the "Three Lines".