| As the source of agricultural production,cultivated land is the essence of land and the basis for ensuring national food security and social stability.However,for a long time,along with the rapid development of the social economy,the contradiction between people and land has become increasingly prominent.In China,the problem of “heavy quantity,light quality,neglecting ecological protection” exists in the development and utilization of cultivated land.Under the background of ecological civilization construction,it puts forward higher require ments for the protection of cultivated land,and it is imperative to realize the trinity comprehensive supervision of the quantity,quality and ecology of cultivated land.According to the connotation of trinity protection of cultivated land,this paper sorts out the idea of comprehensive supervision of cultivated land,and starts from the three aspects of quantity,quality and ecology of cultivated land to construct a trinity evaluation index system for cultivated land in the mountainous county based on the actual situation of the study area.With the support of multi-source data such as remote sensing images,sampling survey data and statistical data,using niche-fitness model to evaluate the niche fitnesses of cultivated land in Qixia City in 2003,2011 and 2015,and comprehensively analyzing the changes of cultivated land niche fitness in the city for many years with the help of land natural classification and transfer matrix.The main results are as follows:(1)This article constructs a trinity evaluation index system based on the quantity,quality and ecology of cultivated land in mountainous areas.Under the goal of trinity comprehensive evaluation of the quantity,quality and ecology of cultivated land,it is divided into three levels: quantity,quality and ecological status of cultivated land,taking into account the proportion of cultivated land,supply capacity,natural basis(endow ment),farming conditions,natural disasters,environmental quality,landscape pattern and bio-safety.The factors are subdivided into 19 indicators such as per capita grain yield,slope and soil erosion.(2)Comprehensive evaluation of the niche fitness of cultivated land in Qixia City.In 2003?2011 and 2015,the average quantity status niche fitness of cultivated land in Qixia was 0.513,0.496,and 0.415,the average quality status niche fitness of cultivated land was 0.599,0.572,and 0.619,and the averagw ecological status niche fitness was 0.670,0.682,and 0.677.Considering quantity,quality and ecology status,the niche fitness of cultivated land in Qixia is 0.610,0.609 and 0.593,with the niche fitness of the western region and the town at northern part of the city is high,which in the eastern region is low.(3)Based on land natural classification rules of the mountainous county,finding out the changes of cultivated land under different conditions by the evaluation results.In 2003-2011 and 2011-2015,the transfer between the sloping brown soil(31)and the brown soil(21)of the terraced land,forest land and construction land was main.And the niche fitness of transferred cultivated land is almost between 0.45 and 0.75.(4)Study the changes in the niche fitness of cultivated land in different years,and explore the balance of arable land.From the perspective of niche fitness of cultivated land,in 2003-2011,the range of cultivated land that was unsuitable,mildly suitable,moderately suitable,and highly suitable for four types of niche fitness was reduced.The niche fitness of new and reduced cultivated land is mainly light and moderate,and the cultivated land is not balanced.From 2011 to 2015,the range of lightly and highly suitable cultivated land expanded,the moderately suitable cultivated land narrowed,the amount of cultivated land is basically equal,and the niche fitness of new and reduced cultivated land was mainly light and moderate.The niche fitness of cultivated land occupation and compensation is balanced,with a tendency to develop in a good direction. |
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