Characteristics And Driving Forces Of Cultivated Land Dynamic Change In The Mongolia During The Last 20 Years

Land is the foundation of the survival and development of human society and an essential element of all production and management activities,and cultivated land is an important part of the land.Mongolia,adjacent to the northern part of China,is a country dominated by animal husbandry and mining industry.The planting industry started relatively late and there are few land resources suitable for farming.With the acceleration of urbanization,the phenomenon of construction land occupying cultivated land has increased.The increase in population has also led to many environmental problems.How to alleviate the contradiction between people and land,effectively protect existing cultivated land,and ensure food security has become an urgent problem to be solved in Mongolia.Taking Mongolia as the research area,this paper expounds the origin,development and present situation of cultivated land on the basis of on-the-spot investigation and collecting a large amount of data.Based on the three images of Mongolia in 1997,2007 and 2017,the spatial data of cultivated land were obtained by visual interpretation using ArcGIS platform.The spatial and temporal changes of cultivated land in Mongolia were analyzed by using land use dynamics,gravity center transfer model and ArcGIS overlay analysis tools.On the basis of the above,combining spatial data and economic data,the driving force of spatial and temporal change of cultivated land is analyzed by using geographic detector model.Finally,the actual situation of Mongolia is discussed.The results show that:(1)During the study period,the area of cultivated land in Mongolia experienced two processes,namely,reduction first and then steady increase.On the whole,the area of cultivated land showed an increasing trend,with a total increase of 99,800 hm~2.The period from 1997 to 2007 was considered as the reduction of cultivated land,and the area decreased from 122.8×10~4hm~2 in 1997 to 70.45×10~4 hm~2 in 2007,with a total reduction area of52.35×10~4 hm~2,of which,the maximum annual rate of change occurred in2001,with the amount of-35.94%.The year during 2007-2017 was deemed as a period of steady increase concerning cultivated land in Mongolia,with a total increase of 62.33×10~4 hm~2,of which,the maximum growth rate appeared in 2017,with an increase of 26.01×10~4 hm~2 on year-on-year basis,and the increasing range was 24.36%.From the perspective of land utilization,the change of reclamation rate showed a trend of rising first and then descend,while the multiple cropping index was in a volatility growth trend.(2)The relative change rate of cultivated land in different provinces and cities of Mongolia is obviously different in space.The largest change rate of cultivated land is 4.031%in Budor Province,and the smallest is 0.458%in Bayan Urigai Province.During 1997-2017,the center of gravity of cultivated land shifted from 8429.83m to northeast,then to 2042m to southeast,indicating that the distribution of cultivated land in Mongolia changed greatly during this period.(3)According to the geographic detector model analysis,the order of the driving factors influencing the spatial change of cultivated land between 1997and 2007 is:average temperature>total livestock>grain yield>population>rural population>Plantation policy,and the average temperature and total livestock have the greatest impact on the spatial and temporal change of cultivated land.From 2007 to 2017,the order of the driving factors influencing the spatial change of cultivated land is:urbanization rate>urban and rural settlements and other land use>population>grain yield>rural population>Plantation policy.The urbanization rate has the greatest impact on the spatial and temporal change of cultivated land.The interaction of each influencing factor shows two-factor enhancement or even non-linear enhancement.