The Comprehensive Evaluation Of Soil And Water Resources Carrying Capacity In The Yangtze River Economic Zone

The Yangtze River Economic Zone is a regional economic coordinated development region established around the Yangtze River Basin,which is an important strategic region for the spatial development of China’s land.With the rapid development of economy and urbanization in the Yangtze River Economic Zone,the sustainable utilization of water and soil resources has been paid more and more attention.Through carrying out the comprehensive evaluation of the bearing capacity of water and soil resources in the Yangtze River Economic Zone,it is helpful to understand the current situation of water and soil resources development and utilization in the Yangtze River Economic Zone and its supporting level for economic and social development,so as to play a supporting role in the rational development and utilization,optimal allocation,scientific protection and management of water and soil resources in the Yangtze River Economic Zone,as well as the opening up of new areas in the Yangtze River Economic Zone.The smooth implementation of development strategy provides theoretical support.In this paper,the Yangtze River Economic Zone is taken as the research area,and the bearing capacity of soil and water resources is comprehensively evaluated.Firstly,the utilization status and trend of soil and water resources in 11 provinces and cities of the Yangtze River Economic Zone are analyzed.Secondly,the matching coefficient method and Gini coefficient method are used to analyze the time variation of the matching situation of water and soil resources in the study area.On this basis,the evaluation index system of water and soil resources in the Yangtze River Economic Zone is constructed and the bearing capacity of water and soil resources and water resources subsystem,land resources subsystem,economic subsystem,social subsystem and environment subsystem of the index system are calculated.Then,based on the coupling and coordinated development model,the coupling and coordinated development of the sub-systems of the evaluation index system of water and soil resources in each province is analyzed.Finally,based on the analysis method of obstacle degree,the paper sorts the soil and water resources bearing capacity of each region,and puts forward corresponding strategies to improve the bearing capacity of the five subsystems according to the results of the attribution analysis.The main research contents and conclusions are as follows:(1)Present situation of water and soil resources utilization in the Yangtze River Economic ZoneAgricultural water is the main type of water resource utilization in the Yangtze River Economic Zone,accounting for 52.8%,followed by industrial water and domestic water,accounting for 32.5%and 13.5%respectively,and ecological environment water consumption is the lowest,accounting for only 1.2%.In the study period,all kinds of water use types increased in different degrees,including 8.2%increase in agricultural water,6.5%increase in industrial water,35.1%increase in domestic water,and 4.6%increase in ecological water.The land use type of the Yangtze River Economic Zone is mainly forest land,followed by arable land and grassland.Among them,the forest land area accounts for 46%,the cultivated land area accounts for about 30%,the grassland area accounts for 16.5%,and the water area and construction land account for about 3%.During the research period,the area of construction land increased most significantly,with an average annual growth rate of 2.34%.The cultivated land area has been reduced continuously with an average annual reduction rate of 0.3%.Woodland area increased before 2010 and decreased after 2010.(2)Analysis on the matching of soil and water resources in the Yangtze River Economic ZoneIn 2005-2017,the matching degree of water and soil resources in the Yangtze River Economic Zone was slightly higher than the national average level.On the provincial and municipal scale,the region with the highest matching coefficient of water and soil resources was Jiangxi Province,reaching 3.43;the region with the lowest matching coefficient was Shanghai,only 0.26.On the regional scale,the matching coefficient of soil and water resources:middle reaches>upper reaches>lower reaches.Based on the correlation analysis of the time change of the matching degree of water and soil resources in the Yangtze River Economic Zone from 2005 to 2017,the absolute value of the correlation coefficient is 0.6,which has passed the significance test of P<0.05.It shows that Gini coefficient method can be used to analyze the change trend of matching degree of water and soil resources.(3)Spatial and temporal changes of soil and water resources carrying capacity in the Yangtze River Economic ZoneFrom 2005 to 2017,the bearing capacity of water and soil resources in the Yangtze River Economic Zone increased from 0.428 to 0.654,showing an overall upward trend.In 2005-2007,the bearing capacity of water and soil resources decreased from medium level to lower level;in 2007-2013,the bearing capacity of water and soil resources showed an upward trend,but the increase rate was relatively slow,except that the bearing capacity of water and soil resources in 2012 was medium level,the remaining years were still lower level;in 2013-2017,the bearing capacity of water and soil resources increased from lower level to higher level,and the bearing status of water and soil resources was obtained Significant improvement.On the scale of provinces and cities,the annual bearing capacity of water and soil resources in Shanghai is the highest,that in Anhui is the lowest,and there is little difference in other areas.On the regional scale,the carrying capacity of water and soil resources:lower reaches>upper reaches>middle reaches.(4)Analysis of coupling degree and coordination degree between water and soil resources carrying capacity systems in the Yangtze River Economic ZoneFrom 2005 to 2017,the coupling degree between the water and soil resources carrying capacity subsystems of the Yangtze River Economic Zone increased first and then stabilized.On the provincial and municipal scale,the coupling degree of water and soil resources carrying capacity subsystem in Hubei Province is the highest,and that in Shanghai is the lowest.On the regional scale,the coupling degree is as follows:middle reaches>lower reaches>upper reaches.As a whole,the coupling degree of the water and soil resources carrying capacity subsystem in the Yangtze River Economic Zone reaches a high level.From 2005 to 2017,the coordination degree between the water and soil resources carrying capacity subsystems of the Yangtze River Economic Zone showed a slow increase trend.On the provincial and municipal scale,Shanghai has the highest degree of coordination,while Anhui Province has the lowest.On the regional scale,the degree of coordination is as follows:lower reaches>middle and upper reaches.On the whole,the coordination degree of the bearing capacity system of water and soil resources in the Yangtze River Economic Zone is low.The correlation coefficient between the annual average water and soil resources carrying capacity and the annual average coordinated operation in 11 provinces and cities is 0.95,which shows that the improvement of the water and soil resources carrying capacity in each province and city is closely related to the coupling and coordinated development of its subsystems.The improvement of the regional water and soil resources carrying capacity can be promoted by strengthening the coordinated development of the five subsystems in each region.(5)Analysis on the factors influencing the carrying capacity of soil and water resources in the Yangtze River Economic ZoneThe main obstacle factors affecting the carrying capacity of water and soil resources in the Yangtze River Economic Zone are GDP per capita,economic value of water resources per unit and comprehensive land output rate,which can be attributed to economic factors.On the scale of provinces and cities,due to the different stages of economic development and resource endowments,there are obvious differences in the ranking of obstacles.In this study,the main obstacle factors were analyzed separately according to the ranking of obstacle factors in each province.In view of the whole Yangtze River Economic Zone,from the five subsystems of the bearing capacity of water and soil resources,this paper puts forward corresponding strategies to enhance the bearing capacity of water and soil resources,in order to promote the sustainable development of the economic society of the Yangtze River Economic Zone.