Driving Factors And Security Evaluation Of Cultivated Land Dynamic Change In Underdeveloped Agricultural Areas

The dynamic change of cultivated land is related to the security of grain production and the deployment of major national strategies.It is the lifeblood of national economy and people’s livelihood.In recent years,scholars have extensively focused on the intensive use of cultivated land,driving change,protection and utilization of cultivated land from multiple perspectives and quantitative analysis methods to provide suggestions for local food production security.Not only make local grain production get bigger improvement,also make it become the hot topic of industry wide discussion.It is more representative to study the dynamic change of cultivated land for the peasant households in less developed areas because of their great mobility.In this paper,based on the 30-meter fine land cover dynamic monitoring data of Chinese Academy of Sciences,OSM road network data,DEM elevation data,CNKI literature data,questionnaire survey data,yearbook statistics and other data,Gephi and ROST were used to analyze the meaning of network hot words related to "cultivated land" in the past 20 years.It is found that the focus of literature is mainly on policy formulation and quantitative analysis.The analysis of its connection degree and clustering coefficient shows that "monitoring" and "response" indexes are in a low range,and the values of "utilization","driving force" and "change" are all high,which is worth exploring its internal driving mechanism.Selection of space syntax,generalized additive model,geographical detector,nuclear density analysis,from human activities,space configuration,the natural factor and the heterogeneity of farmers in four aspects,to detect driving factors,analysis the driving factors influence on the dynamic change of cultivated land utility,at the same time,analysis the influence factor of influence mechanism.The study found that human activity had the greatest impact on "farmland dynamics." Among them,the dynamic decrease of cultivated land area caused by industrial and commercial activities is mainly reflected in the ground collapse caused by mineral mining,the destruction of farmland caused by groundwater flooding,the wastage of cultivated land caused by the later relocation and the reduction of cultivated land caused by infrastructure construction.In agricultural activities,the early farmland development such as "slope to land" and "ladder to land" and the construction of agricultural facilities are the fundamental reasons for the dynamic increase of cultivated land in the study area of farmland construction.The influence of spatial configuration and natural factors on the dynamic change of cultivated land was mainly reflected in the original accumulation period of cultivated land.The influence of farmers on the "dynamic change of cultivated land" is mainly reflected in the loss of rural young and middle-aged labor force and land circulation caused by "income difference".Finally,the PSR model was used to construct the evaluation system from pressure,state and response layer,and the index weight was calculated to evaluate the cultivated land security of 16 towns in Song County.The superposition analysis method was used to sort out the existing problems of cultivated land and put forward reasonable suggestions based on this.The results showed that the cultivated land in Song County had the following problems:(1)There was a "north-south difference" in the cultivated land security in Song County,which was caused by the difference of development difficulty caused by natural factors and then the difference of cultivated land stock.With the development of tourism and other industries,the service industry in the form of "farmhouse entertainment" began to emerge and gradually replaced the "traditional farming",which led to the further decrease of the multiple cropping index of cultivated land,the further decrease of farmers’ planting enthusiasm,and increased the load pressure of cultivated land.On the other hand,farmers in the areas adjacent to specialized tourism villages with homogeneous natural endowment tend to migrate for work due to the "income difference" between agriculture and labor,which leads to the gradual "hollowing out" of farmland circulation and wastage,aggravating the load pressure of farmland in the north and forming a spatial pattern with greater north-south differentiation.(2)Natural disasters threaten the security of cultivated land.According to vector superposition analysis,some cultivated land pattern overlaps with disaster frequent spots in Songxian county,which endangers agricultural property.The dynamic decrease of cultivated land and low multiple cropping index existed in these overlapping areas.Aggravated the load pressure of arable land in this region.(3)There are conflicts between "ecological protection" and "cultivated land protection".In the superposition analysis,it is found that there are overlapping areas between "ecological protection red line" and "permanent prime farmland",and there are conflicts between "ecological protection" and "farmland protection".The driving factors analysis showed that the agricultural activities such as "slope to land" and "ladder to land" in the late 20 th century and the early 21 st century were the main driving factors for the dynamic increase of cultivated land in Songxian county.Industrial activities and infrastructure construction are the main driving factors leading to the dynamic decrease of cultivated land.The results of the generalized additive model show that the effect of agricultural activities on the dynamic increase of cultivated land is nearly linear,and there is a strong correlation between the dynamic change of cultivated land and the value of average depth in the spatial configuration.Among the natural factors,terrain has a great restriction on the development of cultivated land,and the dynamic decrease of cultivated land caused by natural disasters is also obvious.According to the above analysis results and the problems found,Song County should: 1)reduce the farmland in the disaster site,"return the farmland to forest" to restore vegetation and alleviate the disaster;(2)The cultivated land within the "ecological protection red line" was withdrawn in an orderly manner;(3)The cultivated land pressure in the south shifted to the north in an orderly manner,realizing the complementarity between the north and the south.(4)On the basis of "permanent prime farmland",the boundary area with obvious enhancement effect of interaction factors of geographical detectors was selected as the protection surface outside the control line to expand the protection scope of cultivated land.