Determination of the rigid and flexible space for cropland control under the perspective of conflict of “three lines” of territorial space

Cultivated land has been one of the most vital resources and environmental elements for the human survival. However, the purely administrative rigid control cannot effectively meet the needs of urban and rural residents for the multiple functions of cultivated land. It is a high demand to coordinate the conflict between the “three lines” of territorial space and the multi-functionality of cultivated land. In this study, the control zones of cultivated land were constructed to complement the rigid control and flexible guidance, in order to realize the efficient and multi-functional use of cultivated land resources. The example was taken as Guangxi Hechi municipal jurisdiction. Firstly, the LESA system was applied to evaluate the level of regional quality of cultivated land, in order to preliminarily obtain the permanent basic and general farmland zones; The circuit resistance theory and the least cost path (LCP) model were selected to construct the ecological security pattern, in order to delineate the ecological protection red line; The construction land expansion was analyzed using the Geo-detector model. The urban development boundary was obtained from the dynamic simulation of the land use situation in 2035 using the Mixed Compartmental Cellular Automata (MCCA) model. Four scenarios were identified under the “three lines” conflict area after basic evaluation. The amendment rules were formulated to classify the cultivated land. The results show that: 1) The overall quality of cultivated land was at a medium-low level, most of which were II, IV and V levels. The area of permanent basic farmland was initially delineated to be 795.46 km², according to the threshold effect; 2) The preliminary delineation of permanent basic farmland was in the serious conflict with the ecological protection red line and the urban development boundary, with an area of 212.39 km². The conflicting areas were optimized to ultimately obtain a reasonable permanent basic farmland area (i.e., rigid control area); 3) The general farmland outside the rigid spatial scope was amended for the flexible guidance zone. Three kinds of multi-functional zones of cultivated land were coupled within the spatial scope (production-ecological, production-livelihood and ecological-ecological-livelihood compound utilization zone). In view of different control zones, the control idea of “rigid and flexible” was proposed for the cultivated land system. Differentiated control measures were emphasized in use control, such as “what can't be done”, “what can be done” and “how can be done”. The rigid and flexible zoning of cultivated land was greatly contributed to the Hechi municipal jurisdiction. More refined management of cultivated land was formulated to implement the multifunctional and sustainable use of cultivated land. In conclusion, the rigid and flexible spatial delineation of cultivated land can accurately support the effective implementation of spatial planning, in order to realize the win-win situation of territorial spatial planning and the protection of cultivated land resources.