The Classification Of Land Types In Changsha And Its Coupling Analysis With Agricultural Land

As the material space carrier of human production and living activities,people’s food,clothing,housing and transportation are inseparable from the support and bearing of the land.The management of land is also an important part of the government’s public management function,which depends on a well-defined land resource management system.In terms of the spatial scope of management,the hierarchical system of land resource management is mostly consistent with the national administrative division system.However,with the deepening of the interaction between materials and information between regions in the process of economic and social development,the importance of regional collaboration,ecological protection and governance has become increasingly prominent.In addition to the administrative divisions,it is necessary to supplement them with a geographical spatial unit that spans administrative divisions and follows the distribution of the natural environment as the basic analysis unit of land resource management.Therefore,this paper draws on the relevant theories and methods of land type research,and take Changsha as the research area to divide the land type units.Then use it as a basic analysis unit to statistically analyze the current structure and suitability spatial distribution of agricultural land in each land type.And on this basis,we can identify the potential land use development and potential land use conflicts among different land types.In order to explore the division and application of geographical units reflecting the natural background conditions on the city scale.The main research contents and conclusions of the paper are as follows:(1)The system of land type classification.Through the geographical single factor classification and its combination,five land type unit classification schemes based on geomorphic type,soil type,soil sub type,soil type + geomorphic type and soil sub type + geomorphic type are formed.According to the height of topographic relief and altitude,the geomorphic types of Changsha are divided into six categories,which are low hills(36.00%),high hills(20.51%),platform(19.86%),plain(14.74%),low mountains(8.85%)and middle mountains(0.04%)in order of area proportion.According to the system of soil genesis classification in China 1978,there are 9 soil types and 12 soil sub types in Changsha,among which the total area of red soil and paddy soil accounts for about 90%.On this basis,the results of geomorphic classification,soil type classification and soil sub type classification are superposed to form 39 and 54 land types.(2)Evaluation of land type classification.The evaluation index system is constructed to evaluate each classification scheme,and the relatively superior scheme guided by classification purpose is selected.Considering that the results of land type classification should reflect the spatial differentiation of geographical elements and be convenient for land resource management,we construct the spatial differentiation significance index of geographical elements represented by similarity index and heterogeneity index,and the scale suitability index represented by average patch size,area weighted average shape index and average proximity index to evaluate each classification scheme quantitatively.Our purpose is to get a land type unit classification scheme with relatively large similarity degree of geographical elements in the same land type;relatively large differentiation degree of geographical elements among different land types;relatively low fragmentation degree,relatively regular shape,relatively high spatial agglomeration degree of land type patches.On the basis of index value calculation,ranking and scoring are carried out,and the comprehensive scores from small to large are geomorphic type scheme(12 points),soil type scheme(15 points),soil sub type scheme(15 points),soil type + geomorphic type scheme(16points),soil sub type + geomorphic type scheme(17 points).Therefore,the land type classification based on soil sub type + geomorphic type is closer to the purpose of classification,and it is used for the next analysis.(3)Coupling analysis of land use.Taking the land type unit as the basic analysis unit and the agricultural land as the main analysis object,the coupling analysis of land use is carried out,which mainly focuses on the analysis of land development potential and potential land use conflict.Firstly,the land suitability evaluation and suitability level classification are carried out by using the logistic regression model;and then,based on the suitability evaluation,the identification and analysis of land development potential and potential land use conflict are carried out.On this basis,the distribution of land development potential and potential land use conflict in each land type is analyzed,and the possible land use coordination direction in is proposed.As a whole,in the land types that geomorphic type is plain and platform,agricultural land is mainly cultivated land,cultivated land and garden land have great potential for development,potential land use conflicts mainly exist between cultivated land and garden land.In the process of land use,it is necessary to control the occupation of high-quality cultivated land by garden land,and effectively protect cultivated land to ensure food production.In the land types that geomorphic type is hills and mountains,the agricultural land is mainly forest land,forest land and meadow land have great potential for development,the potential land use conflict mainly exists between forest land and meadow land.In the process of land use,we can take the measures of returning farmland to forest or grassland according to local conditions and the principle of suitability matching.