Delimitation Of The Red Line For The Permanent Basic Farmland Based On The Comprehensive Evaluation Of The Arable Land Quality In Yuhang

Arable land is the basis and irreplaceable material for agriculture production.Arable land bears the burden of national food security,while it also has ecological functions and landscape values.So delimiting the red line of permanent basic farmland has a great importance.In this context,this paper chose Yuhang District as the research area to study the delimitation of the permanent basic farmland.And main conclusions are as follows(1)The paper evaluated the comprehensive quality of the arable land from four aspects,which are natural quality,utilization condition,site condition,space form,and used Analytic Hierarchy Process and Delphi method to determine the weight of index.The result of evaluation shows that the overall quality of arable land in Yuhang District is good,and the average of comprehensive evaluation score is 80.1.(2)To guarantee the bottom line of food security,it is predicted that the basic grain demand of Yuhang District will be at least 369,300 tons in 2020.If the grain yield is stable at 7028kg/hm2 and the multiple cropping index is 1.87,28100hm2 of arable land will be able to guarantee the basic food production capacity.In other words the bottom line of arable land in Yuhang is 281 OOhm2,accounting for 76.25%of the arable land.(3)The paper excluded the arable land which is not suitable for the permanent basic farmland based on the relevant planning.The remaining arable land was classified into the permanent basic farmland according to the comprehensive evaluation score,and when the threshold was set at 70 points,the area of the permanent basic farmland area was 28109.51 hm2.accounting for 76.28%of the arable land,which is slightly higher than the target.(4)In order to protect the arable land appropriately,this paper divides the permanent basic farmland into the demonstration zone and the protection zone according to the comprehensive quality.The area of demonstration zone is 9365.26 hm2,accounting for 33.32%of the permanent basic farmland,which is mainly distributed in the water net plain area.All construction activities are prohibited in demonstration zone expect the major project approved by the state council.The area of protection zone is 18744.26hm2,accounting for 66.68%of the permanent basic farmland,which is distributed in all the townships.Compared with the demonstration zone,control measures in protected areas is more flexible,it allows key projects and public projects to occupy the arable land after approved.(5)Based on the comprehensive evaluation of arable land and the prediction of protection index,the paper proposed a clear and quantified standard for the delimitation of the permanent basic farmland.Through the analysis of the permanent basic farmland,conclude as follows:The comprehensive quality of the permanent basic farmland is better than the current ones,and the distribution is reasonable.The protection index issued by the administrative orders does not meet the actual conditions of Yuhang District,it is suggested that the protection index of the permanent basic farmland should be reduced to 28100 hm2.