| Cultivated land is a precious natural resource.It plays an important role in ensuring national food security and sustainable development of economy and society.With the continuously development of urbanization and industrialization,a large number of limited arable land has been occupied,and the number of cultivated land has decreased sharply.As an important part of Chengdu economic belt,Deyang and Mianyang is the core area of urbanization development,their per capita arable land area is decreasing.At the end of 2014,47% of the county per capita arable land was less than 0.053hm2(warning line of per capita arable land as FAO defined).Under the great background of “five synchronization” and “not only both eating,but also construction”,cultivated land protection and food security has become the issues that need special attention of governments at all levels and the state land administration.This study summarized previous research results on the basis of cultivated land pressure and food security issues,adopted the land pressure index model proposed by Prof.Cai Yunlong to estimate the cultivated land pressure index of 2000-2014 of 15 counties(districts,cities)in Deyang and Mianyang areas.The temporal-spatial evolution characteristics of cultivated land pressure data was analyzed by using ArcGIS10.2 software,and the value of cultivated land pressure index of the 15 counties(districts,cities)in the next 10 years was forecasted by adopting the grey GM(1,1)prediction model and put forward corresponding cultivated land protection mode.The main conclusions were listed as follows:(1)During the period of 2000-2014,the increase tendency of cultivated land pressure index was recorded in 15 counties(districts,cities)of Deyang and Mianyang areas,and the tendency of other counties was relatively slow except Fucheng district and Beichuan County.At the end of 2014,there were 7 counties(districts,cities)with the most obvious cultivated land pressure including Fucheng district(K=3.7542)>Beichuan county(K=2.3237)> Jingyang district(K=1.3687)> Pingwu county(K=1.3078)> Jiangyou(K=1.3048)> Youxian district(K=1.1141)> Shifang city(K=1.0125).The cultivated land pressure of remaining 8 counties(districts,cities)was not obvious,and their pressure index of cultivated land was less than 1.In terms of the change rate of cultivated land pressure index,Fucheng district(138.14%)>Beichuan county(133.37%)>Pingwu county(50.30%)>Jingyang district(41.44%)>Youxian district(34.28%)> Jiangyou(31.72%)> Shifang(27.66%);Among the 8 counties(districts,cities)which cultivated land pressure was not obvious,the change rate of cultivated land pressure index in Luojiang county was as high as 42.32%,which was far more than the other 7 counties with unobvious farmland pressure.It could be summarized as that the change rate of cultivated land pressure was not completely consistent with that of cultivated land.(2)From the aspect of spatial differentiation,the variation process of cultivated land pressure index was different from 2000-2014 in 15 counties(districts,cities)of Deyang and Mianyang areas,and it was more obvious in the central and northwest county Among them,the cultivated land pressure areas mainly distributed in the main urban areas of the study areas(Jingyang district and Fucheng District)and the northern part of Beichuan County,Pingwu County,Jiangyou city.In terms of the rate of change,among the 15 counties(districts,cities),60% of them were slow variation and slower variation cultivated land pressure in 2000-2007,which included Mianzhu City,Shifang County,Guanghan City,Zhongjiang City,Santai county,Yanting County,Zitong county and Youxian district,the 3 counties with the largest change rate were Youxian district(14.79%),Shifang(13.31%)and An county(12.04%);27% of the them(city,district)were medium variation type;only 13% of them(districts,cities)were rapidly variation type.The medium variation type counties were changed into Pingwu County,Jingyang District and Youxian district in 2007-2014.The types of slow variation and slower variation were increased from 60% to 67%,the newly added the slow variation areas including Jiangyou City,Luojiang county,and there was still not any medium and high speed variation type,but the rapid variation type remained unchanged.(3)From the analysis aspect of moving track of cultivated land pressure center,a southeast to northwest movement tendency of cultivated land pressure was observed in 15 counties(districts,cities)in 2000-2014,which showed that the increasing trend of cultivated land pressure in the northwest county was more obvious.From the analysis of latitude and longitude coordinates change distance,the moving distance of latitude was greater than that of longitude,which indicated that the variation of cultivated land pressure in the area between the north and the south was greater,and the imbalance of the cultivated land pressure was more prominent.(4)From the perspective of prediction,in the next 10 years,the changes of cultivated land pressure in the 15 counties(districts,cities)were different.Generally speaking,the cultivated land pressure increased significantly in the north and the main urban areas,while the arable land pressure decreased in the hilly areas of the southeast.Specifically,there were four types of changes tendency: sharp rise,slow rise,stable and slow decline.(5)Based on the comprehensive analysis of the prediction results,analyzing from the prospective of cultivated land protection and combing with the differences of the each county resource,four kinds of cultivated land use and protection modes were obtained to provide some references for the further specific policy of land protection.They were “Priority protection of cultivated land,stable economic benefits” mode,“Pay attention to the potential and early warning” model,“optimization of cultivated land productivity” and “moderate economy” mode. |
