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

Abstract

[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× 103 around 2000 hectares converted to an average annual decrease of approximately 2.66× 104 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.

Keywords

• cultivated land conversion
• gravity center migration model
• change trajectory analysis
• spatial pattern
• principal component analysis