Spatial Correlation Features And Action Mechanism Research Of The Fragmentation And Quality Of Cultivated Land In Different Landform Areas Of Liaoning Province

China’s large population,the scarce cultivated land resources and the fragmented pattern of cultivated land management lead to the severe challenges of food security.The fragmentation of cultivated land not only affects the improvement of the efficiency of cultivated land utilization and grain production capacity,but also has a correlation and function mechanism with the quality of cultivated land.Through the fragmentation and quality evaluation of cultivated land and bivariate spatial autocorrelation analysis in different geomorphologic regions,using the spatial lag model and spatial error model to study the function mechanism of cultivated land fragmentation on the quality,reveal the spatial correlation characteristics and action relations of cultivated land fragmentation and cultivated land quality,in order to provide the theoretical support and method for the protection of cultivated land quality from the point of cultivated land fragmentation.The results show that:(1)The overall fragmentation degree of cultivated land in western hilly area,middle plain area and eastern mountainous area is relatively light.In the aspect of fragmentation characterization of cultivated land,the area fragmentation degree is the highest,the shape fragmentation degree is the second and the distribution fragmentation degree is the lowest degree.area fragmentation is the main feature of fragmentation of cultivated land in Liaoning Province.The average value of cultivated land fragmentation index indicates that the degree of cultivated land fragmentation from high to low is: eastern mountainous area > western hilly area > central plain area.There are positive spatial correlation in the area,shape and distribution of cultivated land fragmentation and cultivated land comprehensive fragmentation,mainly high-high(H-H)agglomeration and low-low(L-L)agglomeration.The area,shape,distribution fragmentation of cultivated land in the western hilly area are mainly H-H(10.26%),L-L(24.83%)and L-L(26.22%),respectively.The area,shape and distribution of cultivated land in central plain area are mainly L-L agglomeration,with the three categories accounting for 12.55%,28.72% and 26.74%,respectively.The area,shape and distribution of cultivated land in mountainous area are mainly H-H(25.24%),L-L(17.24%)and L-L(21.21%),respectively.(2)The overall level of cultivated land quality in the western hilly area is the lowest,and the high-quality cultivated land is concentrated in the central of the middle plain area and the southwest of western mountainous area.There is a strong spatial positive correlation in global and local levels.Global Moran’s I indicate that the strength of spatial positive correlation is:eastern mountainous area(0.876)>middle plain area(0.826)>western hilly area(0.679).Local H-H agglomeration is distributed in the east of western hilly area,central of middle plain area and southwest of eastern mountainous area,with 12.19%,22.52% and 27.09%.L-L agglomeration is distributed in the southwest of western hilly area,east and west sides of middle plain area and north of eastern mountainous area,accounting for 15.71%,22.19% and16.28%,respectively.(3)Through the bivariate spatial autocorrelation analysis.There is a common negative spatial correlation between the fragmentation and quality of the cultivated land in different geomorphic areas.Among them,the western hilly area is mainly the local high-low(H-L)agglomeration type,high degree of cultivated land fragmentation and low cultivated land quality;middle plain area is mainly local low-high(L-H)agglomeration,low degree of cultivated land fragmentation and high cultivated land quality;the local spatial agglomeration characteristics of the four categories of cultivated land in eastern mountainous area are quite different,the negative effect of the cultivated land shape fragmentation on the quality is more significant,mainly with local H-L and L-H type clusters,the northern part of the mountainous area has high degree of cultivated land fragmentation and low cultivated land quality,the southeast area has low degree of fragmentation and high cultivated land quality.(4)The action mechanism of cultivated land fragmentation on the cultivated land quality in different landform areas is differentiated.The aggregation degree(AI)in the western hilly area is positively correlated with the cultivated land quality.When the AI increases by 1,the cultivated land quality index increases by 0.8156,and when the AI value in the evaluation unit reaches 95.85,the promoting effect on improving cultivated land quality is at the strongest.The patch number(NP)and edge density(ED)in middle plain area are negatively correlated with cultivated land quality.When NP and ED increase 1,respectively,the cultivated land quality index decreases by 0.3438 and 1.2255,respectively,and when the NP value in the evaluation unit reaches 247,the inhibition effect on the improvement of cultivated land quality is at the strongest and the cultivated land quality index is 59.30.The patch number(NP),area-weighted shape index(AWMSI)and average nearest distance(MNN)are negatively associated with cultivated land quality.When NP,AWMSI and MNN increase1,respectively,cultivated land quality index decreases 0.1876,0.20550,and 0.2159,and when the NP,AWMSI and MNN values reach 790,1.84 and 83.68,respectively,the effect impeding the improvement of cultivated land quality is the biggest.And the cultivated land quality index is 60.83,57.57 and 56.98,respectively.