Spatiotemporal Changes Of Cultivated Land Ecological Security And Diagnosis Of Obstacle Factors In Loess Plateau Of Northern Shaanxi Province

In recent years,the Chinese government has attached great importance to the construction of ecological civilization.The report of the 19 th National Congress of the Communist Party of China summarized the innovative measures in the theory and practice of ecological civilization construction in China.In 2019,Xi Jinping pointed out at the Symposium on ecological protection and high-quality development of the Yellow River Basin,the Yellow River basin is of great significance in promoting social economic development and maintaining ecological safety.In the long time,the combination of economic development and ecological protection is the only way for future development.The Loess Plateau in Northern Shaanxi is not only an important part of the Yellow River Basin,but also an important ecological protection barrier in China.In recent years,due to the impact of human activities and the needs of economic development,people’s irrational use of cultivated land resources has led to a series of cultivated land ecological security problems.Therefore,it is of great significance to study the spatiotemporal change process of cultivated land ecological security and the diagnosis of obstacle factors in the Loess Plateau of Northern Shaanxi for the evaluation of cultivated land ecological security and the maintenance of cultivated land ecosystem.This paper makes an analysis with the actual cultivated land ecological environment situation of Northern Shaanxi Loess Plateau,building the "pressure-state-response" model for the cultivated land ecological security evaluation index system of Northern Shaanxi Loess Plateau;then uses the entropy method to calculate the weight of each index,and uses the comprehensive index method to determine the cultivated land ecological security level of Northern Shaanxi Loess Plateau from 2009 to 2018.According to the comprehensive score,this paper analyzes the temporal change and spatial aggregation characteristics of cultivated land ecological security in Northern Shaanxi Loess Plateau from 2009 to 2018,and finally diagnoses the obstacle factors of cultivated land ecological security in Northern Shaanxi Loess Plateau.The main conclusions are as follows:(1)In this paper,the comprehensive index method is used to quantitatively evaluate the ecological security level of cultivated land.According to the natural segment method,the ecological security of cultivated land in the Loess Plateau of Northern Shaanxi is divided into five levels: risk,sensitive,critical security,comparative security and security.(2)From the time sequence change of ecological security of cultivated land in counties,the level of ecological security of cultivated land has increased and decreased.Mizhi County,Zizhou County,Qingjian County and Luochuan County in Northern Shaanxi Loess Plateau are rapid development areas,while Shenmu City,Suide County,Yanchang County,Ganquan County and Zichang County are slow development areas.Other counties(cities,districts)showed a downward trend,Fugu County,Jingbian County,Jia County,Wubao County,Wuqi County,Huangling County,Yuyang District and Baota District were slow decline areas,Hengshan District,Dingbian County,Zhidan County,Fuxian County,Yichuan County and Huanglong County were slow decline areas,Yanchuan County and Ansai District were fast decline areas.(3)In recent ten years,the comprehensive index of cultivated land ecological security in the Loess Plateau of Northern Shaanxi has been fluctuating.From 2009 to2013,the comprehensive index of cultivated land ecological security decreased slowly;from 2013 to 2014,the comprehensive index of cultivated land ecological security increased rapidly,and gradually returned to a steady rise from 2014 to 2019.(4)At the significance level of 5%,there is a positive spatial autocorrelation about the overall Moran index of cultivated land ecological security in 2009,2014,2017and2018.There is an obvious spatial agglomeration effect in the level of cultivated land ecological security in each county(city,district).In the study area,the high value agglomeration areas are mainly distributed in Huanglong County,Luochuan County,Suide County and Wubao County,while the low value agglomeration areas are mainly distributed in Ganquan County,Baota District,Yanchuan County and Yanchang County.(5)Combining with the scores of pressure,state and response barriers,the cultivated land ecological security barriers in different counties of the region were divided into(response barriers > pressure barriers > state barriers),(response barriers >state barriers > pressure barriers),(state barriers > pressure barriers > response barriers),(state barriers > response barriers > pressure barriers)and(pressure barriers > state barriers > response barriers).The spatial distribution of resistance types shows that the obstacle degree of system state is dominant in the South and north of the region,and the obstacle degree of system response in the middle of the region is greater than that in the north and south.(6)The conclusions showed that:(1)The cultivated land area per capita,grain yield per unit of cultivated land and cultivated land reclamation rate are the main obstacles to the ecological security of cultivated land in the Loess Plateau of Northern Shaanxi;(2)The total power of agricultural machinery per unit area of cultivated land is an important obstacle to the improvement of ecological security level of cultivated land in the economic response layer;(3)Chemical fertilizer load per unit area of cultivated land is an important obstacle factor of environmental pressure layer,while population density is an important obstacle factor of population pressure layer.To sum up,in view of the above conclusions,we can take the following measures:Coordinate the relationship among population,economy and resources,and establish corresponding development plans according to local conditions;Continue to strengthen the protection of cultivated land,cultivate the awareness of cultivated land protection,so that the majority of farmers participate in the protection of cultivated land activities;Continue to strengthen infrastructure construction,and actively prevent agricultural pollution;Reduce the environmental load of cultivated land,we will gradually establish an early warning mechanism and strengthen comprehensive management of agriculture.