| Since the reform and opening up,the evolution of China's urban pattern is mainly based on the incremental expansion model,during which a large area of high-quality arable land has been occupied.In addition,the construction of transportation-oriented infrastructure has caused the fragmentation of farmland landscape.The spatial pattern of high-quality arable land resources overlapping with urban construction space has further increased the concerns of arable land quality degradation such as water and soil pollution.Therefore,the realization of sustainable development has become a key issue to be urgently addressed in territorial space governance.Current researches on cultivated land protection are mostly based on the perspective of land resource management,and have not fully considered the supply-demand relationship of agricultural production.Moreover,the cultivated land protection involved in land resource management focuses on quantitative index management and control,and lacks detailed spatial allocation research.Therefore,it is impossible to analyze and constrain the spatial layout of cultivated land according to the quality and output of cultivated land,resulting in a series of cultivated land protection problems that do not weigh much on quality,such as the basic farmland from the mountains to the seas to the villages.In this regard,this article takes Jiangsu Province as a case area,and optimizes the allocation of cultivated land space from the two dimensions of "quality" and "quantity".The research is mainly carried out through technologies and methods such as model integration,GIS spatial analysis,supply and demand analysis,and quality evaluation.Based on arable land spatial evolution simulation and conflict identification,the arable land productivity prediction and grain supply and demand analysis were carried out,and the comprehensive suitability and quality evaluation of arable land was further carried out,and a research method of arable land "supply and demand balance +" integrated arable land supply and demand analysis,arable land productivity and quality was formed,Conducted research on the optimal allocation of cultivated land space under the background of the expansion of urban construction in the future in Jiangsu Province.The main research contents and conclusions of the paper include:(1)Simulation of spatial evolution and identification of conflicts.Use the Markov-FLUS coupling model to simulate the spatial evolution of cultivated land,and identify the conflict between the future urban construction land space expansion and the current cultivated land space based on the simulation results,as a candidate area for cultivated land optimization;The current permanent basic farmland in conflicting farmland is extracted,and the total area of conflicting permanent basic farmland is used as the constraint threshold of the optimal amount of farmland.The study found that the Kappa coefficient of the simulation results of the Markov-FLUS coupling model reached 0.9487,and the overall accuracy reached 0.9733,indicating that the localized model simulation results based on the actual situation in the study area are reliable and can be used to simulate the future spatial evolution of cultivated land in Jiangsu Province;Conflict farmland identification results show that there are a total of 273,332 potential conflict farmland maps in Jiangsu Province.The potential conflict arable land was 499,563.59 hectares,accounting for 3.99%.The potential conflict permanent basic farmland is 412360.05 hectares.The area of potentially conflicted cultivated land in northern Jiangsu reaches 349,699.98 hectares,accounting for 70.00% of the total conflicted cultivated land.The expansion of urban construction is still the leading factor in the future loss of cultivated land in Jiangsu Province.(2)Prediction of cultivated land output capacity and analysis of supply and demand.Based on the construction of a kilometer-level spatial grid based on the research area,fusion of GIS spatial analysis technology and ANUSPLIN meteorological interpolation model,a gridded DSSAT model is proposed to realize the spatial up-scaling simulation method of the single-point crop model;Carry out localized inspection of crop genetic parameters,use correlation analysis and multiple linear regression models to explore the response mechanism of rice yield formation and meteorological factors;carry out spatial simulation of farmland productivity in Jiangsu Province,and further carry out conflicting farmland supply and demand calculation analysis.The research results show that the simulation effect of the localized DSSAT model is improved and the error is within a reasonable range,which ensures that the arable land productivity simulation results of the DSSAT model are in good agreement with the actual yield;There is a certain correlation between the formation of rice yield and meteorological elements,indicating that the temporal and spatial variation of rice yield can be simulated based on climate change;The future rice yield in Jiangsu Province will be higher in the south and lower in the north(especially higher in the Yangtze River Basin),and much higher in the east and lower in the west;In 2050,the total grain demand in Jiangsu Province will be 32.735778 million tons,the total supply will be 29,256,133.9 million tons,and the grain deficit will be 3,479,964,100 tons.In the future,the scale of arable land in Jiangsu Province will not be able to meet the increasing demand for food.(3)Evaluation and optimal allocation of cultivated land quality.Construct a comprehensive evaluation index system for potentially conflicting cultivated land,and use the AHP comprehensive weighting method to carry out a quantitative evaluation of the comprehensive suitability of cultivated land.Regarding arable land supply and demand and conflicting permanent basic farmland as "quantity" constraints,and arable land productivity and comprehensive suitability of arable land as "qualitative" criteria,the high-suitability conflicting arable map spots are selected in descending order from arable land optimization candidate areas,and the arable land space is optimally allocated.In the end,236,957 optimal plots of potential conflict arable land were selected,with a total area of 438,253.60 hectares.The basic farmland coincidence degree(BFD)is generally close to 60%,indicating that the optimal allocation of cultivated land is reasonable,and the optimization of cultivated land that takes into account both "quality" and "quantity" can achieve a balance between food supply and demand. |
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