| As large agricultural county in the third layers of "Global Chengdu ",Dujiangyan seriously protected farmland,adhered to red lines of basic farmland,strengthened comprehensive improvement of the rural land in recent years.But there still reserves deficiencies of cultivated land,low benefits,and land consolidation is not enough strong in Dujiangyan,and these will be bad for speeding up the modern ecological agriculture demonstration area.In this paper,we measured cultivated land fragmentation degree and analyzed driving mechanism,in order to provide a certain theoretical reference for cultivated land arrangement work,promote regional sustainable development in Dujiagnyan.In this paper,space analysis methods of GIS,landscape pattern index were applied to analyze characteristics of space distribution and evolution of arable land,measuring of cultivated land fragmentation and driving forces of cultivated land fragmentation,the specific conclusions were as follows:(1)The kernel density estimation was gathering in the southeast and fragmented in the north and west.Quadrat analysis indicated that cultivated land were mainly distributed in the southeast.Sample distribution and kernel density distribution was consistent.The plots of cultivated plots in the unit sample were concentrated in the low density area,and the plots of cultivated plots in the unit sample were concentrated in the high density area.(2)Analysis of cultivated land dynamic showed that,compared with from 2005 to 2009,the change of cultivated land was lower from 2009 to 2015.From 2005 to 2009,added arable land was 264.82 hm2,reduced arable land was 2388.36 hm2;From 2009 to 2015,added arable land was 894.95 hm2,educed arable land was 1325.81hm2.A large area of arable land were transferred to urban land,industrial and mining land,transportation land.(3)There were some relations between the spatial distribution characteristics of cultivated land fragmentation and the spatial distribution pattern of cultivated land.The high area of cultivated land fragmentation was mainly distributed in sparse areas of cultivated land that was in the northern and central areas of Dujiangyan.The low area of cultivated land fragmentation was mainly distributed in the cultivated land area that was in the southwest.The comprehensive score of cultivated land fragmentation was 0.6328,0.6365 and 0.5392 respectively in 2005,2009 and 2015,which indicated that the degree of fragmentation of cultivated land increased first and then decreased.(4)In this paper,the relief amplitude,slope,river were selected as natural driving force of fragmentation of arable land.The fragmentation of cultivated land did not increase with the increase of terrain,but it achieved higher value in the platform and hilly terrain where the cultivated land was more concentrated;the slopes were cultivated in each slope,and the fragmentation of cultivated land was higher in the range of 5 ~ 15 °;with the increase of the distance from the river,the degree of cultivated land fragmentation was generally reduced.(5)This paper chose the gross domestic product,the total retail sales of social consumer goods,the total output value of agriculture,forestry,animal husbandry and fishery,the per capita net income of farmers,the urbanization rate,the proportion of the second and tertiary industries,the total population,non-agricultural population,population density as socioeconomic and human driving factors that affected the fragmentation of arable land.Through the analysis of principal component analysis,economic development factors,population factors and industrial structure adjustment factors constituted the social and humanistic mechanism of the spatial and temporal changes of cultivated land fragmentation in Dujiangyan City. |
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