1990—2020年滇中城市群耕地非农化时空变化特征及驱动机制

Spatial and Temporal Changes and Driving Mechanism of Cultivated Land Conversion in Central Yunnan Urban Agglomeration from 1990 to 2020

[目的]通过分析滇中城市群30年耕地非农化的演变路径、时空变化特征及驱动机制,为滇中城市群耕地资源的保护及精准管理提供理论依据。[方法]基于滇中城市群土地利用数据和统计年鉴数据,运用重心迁移模型、变化轨迹模型、空间自相关分析、主成分分析等方法揭示1990—2020年滇中城市群耕地非农化过程、空间分布特征及主要驱动因素。[结果](1)从时间上看,滇中城市群耕地非农化面积呈波动下降趋势,2000年前后由年均增加约6.88×10^(3)hm^(2)转变为年平均减少约2.66×10^(4)hm^(2),受政策、经济和城市化影响导致其变化最剧烈。从空间上看,耕地非农化集中分布于滇中城市群的中部、东部、东南部和东北部地区。(2)30年来,滇中城市群耕地非农化在空间分布上趋于均衡,区域间耕地非农化差异变小,空间格局趋于稳定。(3)滇中城市群耕地主要转出为林地和草地,少部分转化为建设用地,变化型耕地中有54.60%与草地相关,29.33%与林地相关,4.64%与建设用地相关,主要发生在滇中城市群的中部、北部、东南部和西北部的局部区域。(4)滇中城市群耕地非农化存在显著的空间聚集效应,以高—高聚集和低—低聚集为主,高—高聚集主要分布在中部、北部和东南部,低—低集聚主要分布在西北部、西部和西南部。(5)滇中城市群耕地非农化受社会经济和自然条件共同影响。社会经济中的农业人口、国有固定产投资和城市化率是耕地非农化最主要的驱动因素,影响系数分别为-0.18,0.11,0.10;而自然因素年平均降水量和年平均气温在耕地非农化空间分布和扩张过程起着关键性的作用,影响系数分别为0.17,-0.15。[结论]研究结果揭示30年来滇中城市群耕地非农化的时空变化特征、演变路径及驱动机制。对合理利用和保护耕地资源,保障云南省粮食安全具有重要作用,在一定程度上可为滇中城市群的耕地保护和耕地布局优化提供决策参考。

[Objective]By analyzing the evolution path,spatiotemporal variation characteristics,and driving mechanisms of farmland non agriculturalization in the central Yunnan urban agglomeration over the past 30 years,theoretical basis is provided for the protection and precise management of farmland resources in the central Yunnan urban agglomeration.[Methods]Based on the land use data and statistical yearbook data of the Central Yunnan urban agglomeration,the paper used methods such as gravity displacement model,change trajectory model,spatial autocorrelation analysis,and principal component analysis to reveal the process and spatial distribution characteristics of farmland conversion to non-agricultural uses in the Central Yunnan urban agglomeration from 1990 to 2020,as well as the main driving factors.[Results](1)From a temporal perspective,the non-agricultural area of cultivated land in the central Yunnan urban agglomeration showed a fluctuating downward trend,with an average annual increase of about 6.88×10^(3)around 2000 hectares converted to an average annual decrease of approximately 2.66×10^(4)hectares,with the most drastic changes due to policy,economic,and urbanization impacts.From a spatial perspective,the non-agricultural conversion of cultivated land was concentrated in the central,eastern,southeastern,and northeastern regions of the central Yunnan urban agglomeration.(2)Over the past 30 years,the non-agricultural transformation of cultivated land in the central Yunnan urban agglomeration has tended to be balanced in spatial distribution,with smaller regional differences in the non-agricultural transformation of cultivated land and a more stable spatial pattern.(3)The cultivated land in the central Yunnan urban agglomeration was mainly converted into forests and grasslands,with a small portion converted into construction land.Among the variable cultivated land,54.60%was related to grasslands,29.33%was related to forests,and 4.64%was related to construction land,mainly occurring in the central,northern,southeastern,and northwestern regions of the central Yunnan urban agglomeration.(4)There was a significant spatial clustering effect in the non-agricultural transformation of cultivated land in the central Yunnan urban agglomeration,mainly characterized by high-high clustering and low-low clustering.High-high clustering was mainly distributed in the central,northern,and southeastern regions,while low-low clustering was mainly distributed in the northwest,western,and southwestern regions.(5)The non agriculturalization of cultivated land in the central Yunnan urban agglomeration was influenced by both socio-economic and natural conditions.The agricultural population,state-owned fixed asset investment,and urbanization rate were the main factors for the non-agricultural expansion of cultivated land in the social economy,with influencing coefficients of-0.18,0.11,and 0.10,respectively;The annual average precipitation and annual average temperature of natural factors played a crucial role in the spatial distribution and expansion process of non-agricultural land,with impact coefficients of 0.17 and-0.15,respectively.[Conclusion]The results have revealed the spatiotemporal change characteristics,evolution path,and driving mechanisms of farmland converted to non-agricultural land in the central Yunnan urban agglomeration over the past 30 years.It plays an important role in rational utilization and protection of arable land resources and ensuring food security in Yunnan province,and to a certain extent,it can provide a decision-making reference for the protection and optimization of arable land layout in the central Yunnan urban agglomeration.