Study On The Marginalization Of Farmland In Yongdeng County Of Lanzhou City,Gansu Provance,China

The marginalization of farmland is a direct and important reason for the change of farmland use.Meanwhile,the existing farmland marginalization theory system is not perfect,especially for the lack of spatial scale.In order to find out the law of marginalization of farmland in social development of Yongdeng County in Lanzhou City,and to provide the basis for rational utilization and protection of farmland resources.Using RS,GIS technology,through spatial modeling,spatial superposition analysis and Dagum Gini coefficient analysis methods,and use the qualitative and quantitative methods to carried out the spatial and temporal analysis of the marginalization of farmland in the period of 1990 to 2014 in Yongdeng County,Lanzhou City.Research results:(1)In the past 24 years,the first marginalized signs appeared in Yongdeng County before and after 1991,and there was a clear marginalization in the two periods from1999 to 2003 and 2013-2014.Under the driving force of natural factors,the phenomenon of marginalization,which was the longest and the most significant farmland "low-end marginalization" phenomenon from 1999 to 2003.Driven by social development factors,the marginalization of 2013-2014 was more prominent,especially the increase of construction land enhanced farmland "high-end marginalization" phenomenon protruding.(2)Thetownships of higher marginalized farmland rates were Chengguan Town9.98% and Qinchuan Town6.7%,indicating that the two towns were deeper in the "marginalization of farmland".Thetownships of higher proportion of the marginalized farmland were: seven mountain township9.23%,Minle Township7.72%,Shangchuan town7.47%,Qinchuan town7.21%.Indicating that these towns had a wider range of " marginalizationof farmland ".(3)The spatial distribution characteristics of marginalized farmland in Yongdeng County were:(1)The western and northern stone mountain,marginalized farmland was "ladder" distribution;(2)In the loess hilly and gully areas of the central and southern,the farmland presented a "dendritic" distribution and the marginalizedfarmland was distributed in the "shoots" of "branches";(3)Datong River and Zhuanglang Valley,the marginalized farmland showed "sporadic" distribution;(4)East Qin Wangchuan basin,The marginalized farmland distributed in the vicinity of the built areas,which showing to the built aresa "surrounded " distribution.(4)The law of spatial actions for marginalization of farmland in Yongdeng County were: In the two river system areas,the farther away from the river,the higher the degree of marginalization of farmland.The scope of the farmland as a whole to the valley area contraction gathered.The higher the elevation,the more serious the marginalization.The higher the degree of urbanization,the higher the degree of its marginalization.(5)During the study period,the total Dagum Gini coefficient of Yongdeng County was 0.648,and the degree of marginalized farmland in the space showed a high degree of non-equilibrium.The contribution rate of change density was 75.45%,which was the main sourceof the gap in themarginalized farmland.