Research On The Spatio-temporal Evolution Of Cultivated Land Pattern And Ecological Security Of Cultivated Land In Fujian Province From 2005 To 2015

Cultivated land is the basic safeguard for maintaining food security,and it also has important ecological service value.Practically protecting cultivated land is a basic national policy of China,and building a pattern of protecting quantity,quality and ecology of cultivated land is the key task in China.However,affected by urban expansion and the Grain for Green Project,China’s cultivated land protection work is facing severe challenges.Exploring the evolution characteristics of cultivated land patterns and finding the changing rules of cultivated land ecological security status will provide reference for protecting cultivated land,and will provide recommendations for the government to further strengthen the supplement and protection of cultivated land.This paper takes Fujian Province as the research area and the research period is from 2005 to 2015.The research data includes land use data,DEM data,and so on.The main research contents include:(1)Exploring the change characteristics of cultivated land quantity,the spatial attribute characteristics of cultivated land change map spots,and the environmental characteristics of cultivated land change map spots at the patch level.(2)Using the PSR model to construct an index system to calculate the ecological security score of cultivated land in Fujian Province in 2005,2010 and 2015 at the city and the prefectural level.Based on the ecological security scores,the research will explore evolvement rules of the ecological security level of cultivated land from 2005 to 2015 and will use obstacle degree model to identify the factors which limited the improvement of cultivated land ecological security,and build cultivated land’s protection patterns according to different scenarios.The research conclusions are as follows:Evolvement rules of pattern of cultivated land in Fujian Province:(1)Fujian Province achieved a dynamic balance in the amount of cultivated land from 2005 to2015.The number of districts in which cultivated land was at a net loss state increased,while the intensity of loss decreased significantly.The dynamic degree of cultivated land transfer was at a low level.High spots of dynamic degree were distributed in the east,and low spots were distributed in the west.(2)The occupied and the supplemented cultivated land patches had the same distributed direction(southwest-northeast)in2005-2015.The occupied cultivated land patches were mainly concentrated in the eastern coastal area,while the position of the supplementary cultivated land patches shifted from central and northern area to the eastern coastal area.From 2005 to 2015,the number of occupied and supplemented cultivated land patches became more balanced.The scale of supplementary cultivated land patches was smaller than that of the occupied cultivated land patches in the research period,while the shape of supplemented cultivated land patches was more regular than that of occupied cultivated land patches.(3)The cultivated land resources showed trends of “elevation rising”“slope rising” “shifting to shady slope” and “away from water” in 2005-2010,cultivated land loss mainly occurred in the area where altitude is below 300 m,and the area where slope is below 15°,sunny slopes and the area around the water sources.However,these above situations improved in 2010-2015.In addition,the distribution of cultivated land was more compact from 2005 to 2015.Evolvement rules of cultivated land ecological security status in Fujian Province:(1)The cultivated land ecological security status has improved from 2005 to 2015.Xiamen and Putian have the highest score in Fujian Province.From 2005 to 2015,the pressure on the ecological protection of cultivated land continued to increase,the ecological security status was basically stable,and the response measures were generally effective.(2)The region which has high level of ecological security of cultivated land is in the western and eastern area of Fujian Province,while the lowlevel region is in the central area.The ecological security level of cultivated land has a positive spatial correlation in Fujian Province.High-high agglomeration appears in the eastern coastal area,and low-low agglomeration appears in central and northern area.(3)Constructing three types of cultivated land protection patterns: If the primary task is alleviating the ecological pressure on cultivated land,there are 21 counties in the urgently needed protection area,most of which are located in the city boundary zone;With improving the ecological status of cultivated land as the primary task,there are25 counties in urgently needed protection areas,which distribution likes a belt;With strengthening cultivated land protection measures as the primary task,there are 28 counties in urgently needed protection areas,which are divided into four parts.(4)From2005 to 2015,the obstacle degree of pressure and status increased,and the obstacle degree of response decreased.Differences and identities of obstacle factors coexist in various regions.Soil fertility and environmental protection investment are common reasons that limit the ecological improvement of cultivated land,while cultivated land slope and land consolidation are more prominent in individual places.Above all,Fujian government should take effective measures to protect highquality cultivated land with lower elevation,lower slope,and better light and irrigation conditions.Secondly,the government need to formulate a plan for the protection of cultivated land ecological security,and build a pattern of cultivated land ecological security protection.Thirdly,the government should increase investment in environmental restoration and rural vitalization.Finally,the government should take soil amelioration project,and implement fallow and crop rotation scientifically.