Evaluation Of Cultivated Land Ecological Security And Diagnosis Of Obstacles In The Yangtze River Economic Belt

Nowdays,promoting the development of the Yangtze River Economic Belt is one of the three major development strategies in China.It is of great significance to evaluate the ecological security level of cultivated land in the Yangtze River Economic Belt to protect the regional ecological environment,ensure food security and promote sustainable development.In addition,evaluating the level of cultivated land ecological security and its influencing factors in the Yangtze River Economic Belt is also of great practical significance for guiding the protection of cultivated land,the construction of ecological civilization and the development of high quality in all regions of the Yangtze River Economic Belt.Firstly,the DPSIR model is used to construct the evaluation index system of cultivated land ecological security in the Yangtze River Economic Belt from five aspects:driving force,pressure,state,influence and response.In the aspect of weight determination,which based on the comprehensive entropy weight method and analytic hierarchy process,the subjective and objective combination weights are calculated by multiplicative synthesis method.Secondly,with the help of weighted TOPSIS model,the ecological security comprehensive score of cultivated land in 108 cities evaluated of the Yangtze River Economic Belt in 2017,and the spatial differences were compared from the provincial and regional perspectives.Finally,through the obstacle factor diagnosis model,the main obstacle factors and obstacle degrees of the criterion level and the index level are calculated respectively,in order to provide some suggestions for enhancing the ecological security level of cultivated land in the Yangtze River Economic Belt.The main results are as follows:(1)In 2017,the comprehensive score of cultivated land ecological security in the Yangtze River Economic Belt was 0.386,which was in a critical safety state.Among them,47 cities have Grade Ⅳ cultivated land ecological security,46 cities have Grade Ⅲcultivated land ecological security,12 cities have Grade Ⅱ cultivated land ecological security,only 3 cities have Grade V.There are differences in cultivated land ecological environment in the Yangtze River Economic Belt.By calculating the index scores of five subsystems:driving force,pressure,state,impact and response,it was found that the impact and response subsystems contributed greatly to the ecological security of cultivated land.(2)By comparing the differences of cultivated land ecological security between provinces and regions,it is found that there are spatial differences in cultivated land ecological security in the Yangtze River Economic Belt.The overall level of ecological security of cultivated land presents the layout of "high in the East-low in the west".Among them,the ecological security of cultivated land in Shanghai is up to Grade V.The four provinces of Jiangsu,Zhejiang,Jiangxi and Hunan are at Grade IV.Anhui,Hubei,Chongqing,Sichuan,Guizhou and Yunnan are at Grade III critical safety level.From the index scores of each criterion level,the driving force index and response index scores are basically consistent with the spatial pattern of comprehensive score of cultivated land ecological security.(3)The diagnostic results of obstacle factors show that the obstacle degrees of driving force,pressure,state,influence and response subsystems to the ecological security of cultivated land in the Yangtze River Economic Belt are I 1.86%,11.03%,22.87%,24.78%,29.46%,respectively.It can be seen that the impact and response subsystems have relatively greater impact on the ecological security of cultivated land.In addition,the main obstacles to the ecological security of cultivated land in the Yangtze River Economic Belt are the total power of agricultural machinery per unit of cultivated land,land economic density,per capita water resources,the proportion of tertiary industry to GDP and the annual reduction rate of cultivated land area.The Yangtze River Economic Belt should improve the ecological security level of cultivated land by regulating the main obstacle factors.