Research And Empirical Analysis On The Estimation Model Of Comprehensive Index Of Cultivated Land Quality

In order to evaluate the change of regional cultivated land quality more comprehensively,realize the effective protection of cultivated land quantity,quality and ecology,and rationally improve the evaluation system of cultivated land quality,so as to ensure food security in China,it is of great theoretical and practical significance to study the multi-dimensional evaluation index of regional cultivated land quality.The main objective of this paper is to calculate the comprehensive index of cultivated land quality,and to analyze the change trend of cultivated land quality from three dimensions: the productive potential dimension,land type dimension,and spatial dimension.Among them,the key and the difficult point are to quantify the landscape ecological pattern index of spatial distribution.In this paper,empirical analysis is used as the main research method.Firstly,the hypothesis based on the content of this paper is put forward: the spatial distribution of the cultivated land of different classes and land types has an impact on the regional comprehensive quality to a certain extent.Based on this hypothesis,combined with literature research method,analytic hierarchy process,and landscape pattern index calculation method,a comprehensive index of cultivated land quality for multi-dimensional evaluation of regional changes in cultivated land quality is proposed and a calculation method is constructed.The grade dimension is based on the national utilization data of agricultural land classification and its annual renewal results.In the land category dimension,the land category composition is based on the proportion of paddy field,irrigated land and dry land in the region,and the spatial distribution pattern of different secondary land types and the spatial distribution of different cultivated land types.Based on the actual situation of cultivated land patches and research hypothesis,landscape shape index,perimeter area fractal dimension,spread index,and aggregation index were introduced to quantify the spatial pattern changes of cultivated land in different classes and different land types.In order to facilitate the comparison and understanding,the data of the three dimensions are normalized.The method of calculating the comprehensive index of cultivated land quality is determined based on the weighted value of the analytic hierarchy process(AHP),and an empirical study is carried out.It provides a theoretical basis and technical reference for improving the current assessment standard of cultivated land quality in China.The main findings are as follows:(1)Quantify the spatial distribution differences of cultivated land with different classes.In the part of the theoretical research,based on the results of agricultural land classification and annual quality renewal,combined with the theory of landscape ecology heterogeneity,this study reduced the heterogeneity scale to the cultivated land system itself.It considered that different types of cultivated land were different types,and selected landscape pattern index as a spatial dimension.(2)Discuss the method of calculating the comprehensive index of cultivated land quality from three perspectives: the productive potential of cultivated land,the composition and spatial distribution of land types,and the spatial distribution of cultivated land.Based on the theoretical study on the calculation of the comprehensive index of cultivated land quality,a case study was carried out in Haiyan County,Jiaxing City.It is concluded that the quality of regional cultivated land is related to the average classification of cultivated land,the composition of land types,the spatial distribution of land types and the spatial distribution of land types.(3)The evaluation of cultivated land quality should increase the composition of secondary land types and the spatial distribution of cultivated land in different land types or classes.Based on the above theory and empirical research,it is considered that the future regional cultivated land quality evaluation should not only comprehensively evaluate the location conditions,natural factors and production capacity of cultivated land patches,but also comprehensively consider the shape and area of single cultivated land patches,as well as multiple types of cultivated land patches within a certain evaluation range.The spatial quality difference of cultivated land caused by the pattern distribution and other conditions is quantified in a reasonable way and included as an index in the calculation of regional cultivated land quality.