Analysis Of Migration Mechanism Of Multi-scale Cultivated Land Spatial Network Considering Spatially Inter-city Interactions

In the process of urbanization,the scale of conversion of high-quality arable land to non-agricultural land keeps expanding.Although the balance of land occupation and compensation can be achieved through land development,consolidation and reclamation in different places,the internal spatial structure of arable land has changed.The cultivated land available for reclamation is not only small in scale,but also scattered,many in the mountainous areas raised from the sea.Therefore,it is particularly urgent and necessary to study the dynamic change of the whole cultivated land in the region from the perspective of urban agglomeration by constructing the multi-scale cultivated land spatial network model.Spatial network analysis is an effective method for evaluating spatial structure.Constructing multi-scale cultivated land spatial network model at urban agglomeration scale and county scale,while analyzing the dynamic change of the whole cultivated land structure in urban agglomeration,it can also excavate the extension and internal migration of cultivated land gravity center at county scale.The cultivated land spatial network model can reveal the interaction mechanism between cultivated land elements in the process of urbanization and rediscover and evaluate the law and status quo of cultivated land scale development.In this paper,the central Zhejiang urban agglomeration is taken as the study area.Firstly,the land use data set with spatial resolution of 30 m is adopted to obtain the optimal bandwidth at global and local scales,and finally the optimal search distance of the spatial network model at different scales is determined.At the same time,programming language modeling analysis is used to obtain the visual presentation of the cultivated land spatial network model.Secondly,through the multi-temporal simulation of the spatial and temporal evolution of cultivated land spatial network,we studied the local weakening scope of the radiation effect within the space caused by urban expansion occupying high-quality cultivated land,and whether the new cultivated land developed,reclaimed and replenished has formed the network scale agricultural cultivation mode.Finally,Binary Logistic regression model was used to quantitatively explore the driving factors of cultivated land spatial network migration change,and the internal correlation between the main human disturbance factors such as population and traffic and cultivated land spatial network was explored.With the help of geographic detector method,the detection and analysis model of cultivated land spatial network influencing factors was built,and the driving weight of social and economic indicators on cultivated land spatial network in urban agglomeration was deeply discussed.The main conclusions of this paper are as follows:(1)Spatial network is an effective method to evaluate and analyze the dynamic migration of cultivated land spatial structure in the process of urbanization.Based on the characteristics of the data in different regions,scales and resolutions,and on the basis of calculating the optimal data bandwidth of each year by using geographic information software tools and models,the evaluation model of cultivated land spatial network at multiple spatial and temporal scales can be constructed.(2)There is no uniformity between cultivated land area and cultivated land spatial structure in urban agglomeration in central Zhejiang.A single index of cultivated land area can not fully evaluate the spatial quality of cultivated land,so it is necessary to build an evaluation system of cultivated land spatial structure with multiple indexes.In the regions where the total stock and area of arable land are decreasing,the distribution of internal structure is gradually denser,and agricultural cultivation is highly mechanized,specialized and concentrated.(3)At the junction of Jinhua,Lishui and Quzhou at the county and city scale,the shift of center of gravity of small area farmland network is obvious.The newly reclaimed cultivated land in Jinyun County has not yet formed a strong interaction system with the surrounding cultivated land elements,and the spatial interaction between them is still in the primary stage.The change of spatial network structure of cultivated land in Jinhua urban area can reflect the influence of urbanization on the shift of cultivated land gravity center in Jinhua urban area.(4)Human disturbance factors in the process of urbanization have a certain influence on the spatial structure of cultivated land in the urban agglomeration of central Zhejiang.The migration and change of cultivated land spatial network in central Zhejiang city agglomeration is mainly influenced by the urban population in population scale.The spatial interaction between cities makes the external functional forces have a certain driving force on the change of cultivated land.When the intensity of urban flow is positive,it has a negative driving effect on the scale development of cultivated land spatial network in developed cities.