Study On The Macro-planning And Functions Of Permanent Prime Farmland In Clustered Urban

Cultivated land is an important material basis for the construction of modern agriculture.Permanent prime farmland is the essence of cultivated land,and has a close relationship among the land spatial planning,industrial layout,the urban development boundary and food security.In the past,economic development has priority to the prime farmland,and areas surrounding the city were designated as no farmland.The farmland in the peripheries of 14 major cities including Beijing,Shanghai,Guangzhou,Chongqing and others was to be designated as permanent prime farmland according to the requirement of the Ministry of Land and Resources and the Ministry of Agriculture in 2014,and then it expanded to 106 cities.As the most typical clustered urban,Chongqing was one of cities to be first asked to set up permanent prime farmland around the city.Its unique geographical conditions and city layout determine the complexity of the permanent prime farmland.Therefore,it’s of great significance to study the conservation planning for demarcating prime farmland in Chongqing and further look for systematical and feasible evaluation methods.In this paper,Beibei District of Chongqing was taken as the study area,and the geographical conditions of Jialing River,Jinyun Mountain were taken into account based on the characteristics of high quality,stability and spatial agglomeration of permanent prime farmland.Firstly,the cultivated land quality evaluation system and site condition evaluation system were established to natural quality assessment and stability analysis.Then,the LESA system was used for comprehensive evaluation.According to the results,the spatial correlation degree of cultivated land was analyzedby the method of local spatial autocorrelation.In terms of the main function of permanent prime farmland,this paper compared the difference between the original results and the results of this study to verify the scientificity,the rationality and t he feasibility.The results showed that:(1)The natural quality assessment results are as follows.The natural qualitive score of cultivated land is 24.95-93.11,with an average of 57.36.The cultivated land is a typical hilly area in Southwest.According to the order from high to low,the cultivated land was divided into 5 levels.The high quality cultivated land is circular or zonal distribution in Shuitu Group,Caijia Group and Beibei Group.There is no mountain or slope in these areas,and it has good conditions on soil and agricultural facilities.(2)The results of site conditions are as follows.The index weights of site conditions reflect the influence of different site conditions of cultivated land,and the order of each index was cultivated land to groups distance > construction land expansion rate > non-agricultural population proportion > suitability of adjacent land >the distance to roads > the distance to village > city planning.The interval of posterior probability is from 0.0590 to 0.999,and the mean value is 0.805.Most of the cultivated land has a stable state of cultivation,but there are differences between groups.According to the posterior probability,the cultivated land was divided into 5 levels.As a result of Caijia and Shuitu to develop high-tech industries,the economic growth and urban developed rapidly,and the unstable cultivated land was distributed in the circle around the Caijia and Shuitu.(3)Permanent prime farmland producting planning results are as follows.According to the above results,the cultivated land was divided into prime farmland protection,consolidation area for supplementing prime farmland,general protection area and unsuitable area.The prime farmland protection had excellent natural and social economic attributes,including the first and second level of all High-high type area and other places which score above 80 points.It covered an area of 10087.58 hectares,accounting for 45.84% of the total area of arable land.It is mainly distributed in the characteristic agricultural belt,the leisure traveling area and the high quality ecological and commercial area,and it’s quite different from that in the distribution in each group.The consolidation area is the area of prime farmland adjustment and supplement which is only next to prime farmland protection.There was no obviousadvantage in quality,site condition and spatial distribution in general protection area.And the unsuitable area is easily converted because of the natural environment or urban development.This distribution meets the requirements,and the distribution kept considtency with developing planning in Beibei.Therefore,the permanent prime farmland should be allocated and implemented according to the resource endowment and industrial development of each group.(4)Results of multi-functional analysis are as follows.In terms of production function,the research results had better capacity than before in theory of prime farmland production,actual production and production based on economic benefits.The results of this study can play a better role in providing ecosystem service value,biodiversity and ecosystem stability.In the construction land isolation effect,the results can effectively isolate the urban expansion with Jialing River,Liangshan and Jinyun Mountain.This study compared the delimitation of prime farmland from multi-function,and the results were more perfect.Besides,compared with the former farmland adjustments,the research can avoid the weakening prime farmland function to achieve the Trinity,force the city boundary delimitation and Smart Growth.