Study On The Evaluation Of Cultivated Land In Requisition-compensation Balance Area Based On GIS

In the 21 st century,with the socio-economic development and rapid population growth,the food problem has risen to an important strategic issue,which has profound influence on the national economy and people's livelihood.It is of particular significance in our country whose overall level of cultivated land is relatively low,and whose per capita area of cultivated land is less than the world average.Non-agricultural constructions have been continuously occupying cultivated land,making the food security situation in our country very grim.As a result,China proposed a policy of cultivated land requisition-compensation balance,requiring non-agricultural constructions that takes up cultivated land to supplement cultivated land of the same quantity and quality,in order to ensure the dynamic balance of the total amount of cultivated land.This policy,as an important means of supplementing cultivated land,has strategic significance in guaranteeing the national food security and social stability.However,there is still a lack of effective supervision and feasible method of quality evaluation in the implementation of this policy so far,resulting in the improper emphasis on quantity instead of quality and the phenomenon of substituting the good with the bad in compensation in some areas.Therefore,the present study conducts a research on the evaluation of the quality change of cultivated land in the balanced area,which aims to provide theoretical foundation for ensuring the quality of cultivated land in implementing the policy of requisition-compensation balance.Land suitability evaluation is one of the main contents of land resource researches at home and abroad in recent years.Based on the data of the second national land survey in Huangling County of Yan'an and the data of land use change survey in each year during 2010-2015,the paper makes use of remote sensing,geographic information system and other technologies,extracting the changing areas of cultivated land from the requisition-compensation balance area of Huangling County in the past six years.By making reference to the nationally recommended evaluation system of agricultural land classification and taking full account of the actual situation of Huangling County,the paper,from the point of view of suitability,selects the six indexes of geomorphic position,slope,effective soil thickness,road accessibility,water source guarantee rate and residential radiation influence degree.Then,the paper adopts the improved analysis hierarchy process and the gray relational analysis method to determine the weight of each evaluation factor,Finally,the paper makes use of GIS to construct the suitability evaluation index system of cultivated land of Huangling County,and to analyze and evaluate the quality,and spatial distribution pattern of the cultivated land in Huangling's requisition-compensation balance area.The purpose of the present study is to provide the Land Department with a scientific management and basis for the rational use of cultivated land,and to offer support services for food security decision-making by the government.