Ecological restoration zoning of agricultural land of the Sunan District from the perspective of national land and space governance

Agricultural land is an open semi-artificial ecosystem with interrelated and restricted internal elements, which is characterized by reproducibility, dynamics, and multifunctionality. It is also an important production space to serve as the critical element of rural ecological space. In 2019, the Ministry of Natural Resources issued the Notice on Carrying out pilot Work of Comprehensive Land Consolidation in the whole region, which proposed the protection and restoration of rural ecology for the first time. The guideline aims to protect and restore the rural ecological functions in the biodiversity and natural landscape. Therefore, it is a high demand for the comprehensive restoration of mountains, rivers, forests, fields, lakes, and grass natural resources. A rational division is also the need for ecological restoration areas in the agricultural land from the perspective of territorial space planning and decision making in recent years. A tradeoff can be made between the land ecological function during the ecological restoration of farmland, and the input end of the farmland ecosystem with the dissipation, according to the requirements of national spatial governance and ecological restoration of agricultural space. It is very necessary to realize the coordinated development of all the elements within the system and benefit. In this study, an evaluation framework was constructed for the ecological restoration of agricultural land covering three dimensions of "ecological function, input and dissipation". The Sunan District in the Middle-Lower Yangtze plain was selected as the study area, where the 500 m×500 m spatial grid was used as an evaluation unit on the grid scale. The ecological restoration potential of agricultural land was estimated under two time sections in 2010 and 2018 using spatial analysis of economic and social data, geospatial and mathematical statistical analysis. A scheme was also proposed for the ecological restoration zoning and countermeasures. The results showed as follows: 1) There were significant spatial differences of ecological restoration index, ecological function, input and dissipation of agricultural land in the study area at the same time section. 2) The ecological restoration index of agricultural land increased significantly from 2010 to 2018, with a difference of 0.018 in the study area. The ecological function varied in the different regions. There was also a decreasing trend in the input and dissipation. 3) The study area was divided into four first-level types including the urgent repair, optimized upgrading, the control, and coordination development area, each of which included four second-level types, namely, comprehensive factors, function, dissipative, and input constraint, where there were 15 partitions of agricultural ecological restoration, thereby to propose the repair measures. An evaluation index system on grid scale was established to integrate the ecological function of agricultural land and the impact of human activities on agricultural land (input and dissipation) during ecological restoration of regional agricultural land. The findings can provide an innovative reference for the planning and decision-making framework on the differentiated management of ecological restoration in territorial space.