Spatial And Temporal Variation Of Cultivated Land Quality And Its Influencing Factors In Shaanxi Province

Cultivated land is the most valuable natural resource in contemporary China,which is the key to agricultural production,food security,ecological security and social stability.The researches on spatial-temporal change and driving mechanism of cultivated land in long time series are the basis to find out and improve the quality of cultivated land.Mastering the temporal and spatial variation and differentiation of cultivated land quality,quantitatively analyzing its influencing mechanism,and proposing cultivated land protection measures are necessary to improving the quality of cultivated land in China,optimizing the cultivated land protection system,and promoting the sustainable development of cultivated land.At the same time,they can provide the basis for implementing cultivated land protection policies and ensuring national food security.In this study,Shaanxi Province was taken as the research object.Based on the annual update data of cultivated land quality in Shaanxi Province,combined with the data of influencing factors of cultivated land quality,the dynamic model method,area weighted average method,location index method,gravity center migration model,spatial autocorrelation and hotspot analysis were used to analyze the spatial-temporal changes and differentiation characteristics of cultivated land quantity and quality from2005 to 2018.The correlation analysis was used to study the overall related factors of cultivated land quality.On this basis,by eliminating the factors that did not pass the significance test,the geographical weighted regression model was used to study the effect of various influencing factors on the quality of cultivated land in space.The main conclusions are as follows:(1)In terms of time,the number of cultivated land resources in Shaanxi Province decreased from 2005 to 2018,and the average quality of cultivated land changed smoothly.In terms of quantity :(1)In 2005-2010,2010-2015 and 2015-2018,the total number of cultivated land decreased first,then increased and then decreased.The change of cultivated land was more and more stable.(2)From 2005 to 2018,the higher and lower areas of Shaanxi Province decreased at different levels,and the middle area increased slightly.In terms of quality :(1)The average quality of cultivated land is not high and there is a few changes.From2005 to 2018,the quality of cultivated land decreased slightly,with an average quality grade of 11.31.The quality of cultivated land was lower than the national level.(2)From 2005 to 2018,the quality of cultivated land in most areas of northern Shaanxi and parts of southern Shaanxi showed a trend of improvement,and the quality of cultivated land in Guanzhong area generally showed a downward trend.(2)In terms of spatial,from the perspective of geographical regionalization,the quality of cultivated land in Shaanxi Province presents the distribution pattern of Guanzhong > Southern Shaanxi > Northern Shaanxi.From the perspective of cultivated land classification index area,Guanzhong-Weihe plain area >Low mountains and hills in southern Shaanxi > Shangluo mountain hilly area > Qinba mountains in southern Shaanxi > Weibei loess upland area > Loess hilly and gully region of northern Shaanxi > Sand storm along the Great Wall in northern Shaanxi.From the city level,Yangling Demonstration Zone,Xi’an,Xianyang,Weinan > Hanzhong,Baoji,Ankang,Shangluo,Tongchuan > Yan’an,Yulin;From the perspective of location index : Xi’an,Xianyang,Yangling demonstration zone location index is higher for five,six,seven,eight and other places,belong to higher,Baoji,Weinan,Hanzhong,higher(seven,eight)and medium(nine,ten)location index is higher,Tongchuan,Ankang,Shangluo,medium(eleven,twelve)and low(thirteen)location index is higher,Yan’an and Yulin,low(thirteen,fourteen)cultivated land location index is higher;From the perspective of gravity center migration: the gravity center of cultivated land resources in Shaanxi Province from 2005 to 2018 is located in the loess plateau area of Weibei,and the gravity center of higher land is located in the Qindu,the gravity center of middle land is migrated from Chang’an to Weicheng,and the gravity center of lower land is located in Ansai.Spatial correlation:(1)The spatial distribution of cultivated land quality in Shaanxi Province has significant correlation,and the spatial pattern is relatively stable.(2)High-high type(HH)gathered in Guanzhong,low-low type(LL)gathered in northern Shaanxi;(3)The hot spot area is mainly located in Guanzhong-Weihe Plain,and the cold spot area is located in Sand storm along the Great Wall in northern Shaanxi and Weibei loess upland area.The changes from 2005 to 2018 show a trend of aggregation of hot spots and dispersion of cold spots.(3)In terms of influential factors,the main influential factors of cultivated land quality in Shaanxi Province are the average temperature,the amount of agricultural fertilizer,the total power of agricultural machinery and population density.The most obvious influencing effect of average temperature on cultivated land quality is mainly in the Weibei loess upland area and Loess hilly and gully region of northern Shaanxi.The areas where the application amount of agricultural chemical fertilizer has a significant in promoting effect on cultivated land quality are mainly in the Loess hilly and gully region of northern Shaanxi and Sand storm along the Great Wall in northern Shaanxi.The influencing effect of total power of agricultural mechanization on cultivated land quality is obvious in southwestern Shaanxi and part area of northern Shaanxi.The driving effect of population density on cultivated land quality shows a transitional trend that there is a gradually weak from north to south in Shaanxi Province.Among the driving factors,the influencing variable that mainly inhibits the quality of cultivated land in Shaanxi Province is slope.Slope has an inhibitory effect on the quality of cultivated land in northern and central areas of Shaanxi Province,which are mainly plain cultivated land.In summary,in the future,land consolidation and high-standard farmland construction projects should be actively promoted in Shaanxi Province.According to the influence of natural,social and rural economic factors in different regions of Shaanxi Province,measures about improving the quality of cultivated land should be carried out according to local conditions.