Analysis On Coupling Coordination Of Water-Energy-Food-Environment System And Its Influencing Factors In Shaanxi Province

Water resources,energy and food are the basic and strategic resources for human survival and social economy development.The integrated management of the three resources is very important for the sustainable development of human life and resources.The complex processes of water-energy-food systems are closely related to the carrying capacity of environmental systems.Shaanxi Province is located in the northwest of our country.It is a big agricultural province and one of the important coal industry bases.With the rapid and stable development of economy,the population in this region is increasing,and people’s demand for resources is growing,while the shortage of water resources seriously restricts the development of energy,chemical industry and food.With the continuous progress of urbanization,water environment and atmospheric environment are also under constant threat,so there are prominent contradictions in the water-energy-food-environment system in this region.Current studies of water-energy-food linkages lack consideration of environmental systems.Based on this,this study takes Shaanxi Province as an example,firstly constructs the comprehensive evaluation index system of water-energy-food-environment system,then uses the comprehensive evaluation index model and coupled coordination degree model to reveal the spatio-temporal variation characteristics of the coupled coordination level of water-energy-food-environment system,and finally adopts the random forest method.The influencing factors of coupling coordination degree of water-energy-food-environment system are clarified.The main conclusions of this study are as follows:（1）In terms of water resources,from 2001 to 2020,the total water resources of Shaanxi Province changed greatly,with an average annual value of 38.75 billion m³,while the overall water resources consumption showed an upward trend,with an average annual value of 8.55 billion m³.Water resources consumption in Shaanxi Province is dominated by agricultural water,accounting for 66.4%on average over the years.In terms of energy,from 2001 to 2020,total energy production,total energy consumption,power generation and social power consumption of Shaanxi Province showed an overall upward trend,while energy consumption per unit of GDP and power consumption per unit of GDP showed a steady downward trend.From 2001 to 2020,the total power of agricultural machinery in Shaanxi Province showed an N-shaped growth trend,with an annual average of 188.92billion k W.In terms of food,from 2001 to 2020,the total grain output and per capita grain output of Shaanxi Province showed a shock growth trend,with the annual average of11.587 million tons and 308.0 kg,respectively.From 2001 to 2020,the changes of sown area,cultivated area,disaster area and effective irrigation area of grain crops in Shaanxi Province were different,with an average of 3159.9×10³ hm²,2886.0×10³ hm²,1333.6×10³ hm² and 1280.5×10³ hm² respectively.In terms of environment,from 2001 to 2020,the discharge of waste water and the volume of household garbage in Shaanxi Province showed a fluctuating upward trend,with the annual average of 1.14 billion tons and 4.229million tons.From 2001 to 2020,the emission of industrial waste gas in Shaanxi Province showed an overall rising trend,and the comprehensive utilization rate of general industrial solid waste showed a trend of first fluctuating increase and then decreasing.（2）From the perspective of time,the comprehensive evaluation index of water-energy-food-environment system in Shaanxi Province from 2001 to 2020 ranged from 0.36 to 0.68,showing a significant growth trend on the whole.Among them,the evaluation indexes of water resource subsystem,energy subsystem,grain subsystem and environment subsystem are 0.14-0.70,0.28-0.70,0.32-0.69 and 0.39-0.64,respectively.Although there is a certain range of change,except the food subsystem shows a fluctuating trend,the other subsystems all showed significant growth.From the perspective of space,the comprehensive evaluation index of water-energy-food-environment system showed a higher trend in the central region than in the north and south.The evaluation index of water resources subsystem is higher in southern Shaanxi than in northern Shaanxi and higher in western Shaanxi than in eastern Shaanxi.The evaluation index of energy subsystem is higher in northern Shaanxi than in southern Shaanxi and higher in eastern Shaanxi than in western Shaanxi.The spatial distribution of the evaluation index of the food subsystem and the environment subsystem was different,and the overall trend was higher in the middle than in the north and the south.（3）From the perspective of time,the coupling coordination degree of water-energy-food-environment system in Shaanxi province experienced three stages from2001 to 2020:"M"shape change from 2001 to 2006,inverted"V"shape change from 2006to 2014 and steady-state growth change from 2014 to 2020,showing a significant growth trend on the whole.The coupling coordination level changes from barely coordination to good coordination.From the perspective of space,the coupling coordination degree of southern Shaanxi is higher than that of northern Shaanxi,and the coupling coordination degree of western Shaanxi is higher than that of eastern Shaanxi.Except for Ankang City and Shangluo City,the coupling coordination degree of other cities increases significantly.Among them,the coupling coordination level of Tongchuan City,Ankang City and Shangluo City has transited from primary coordination stage to intermediate coordination stage;the coupling coordination level of Xi’an City,Baoji City,Xianyang City,Weinan City,Yan’an City and Yulin City has transited from reluctant coordination stage to intermediate coordination stage;the coupling coordination level of Hanzhong City has transited from reluctant coordination stage to good coordination stage.（4）From the perspective of the water-energy-food-environment system as a whole,there are 19 indexes that have significant influence on the coupling coordination degree of Shaanxi Province.In order from high to low,they are household garbage removal volume（S8）,general industrial solid waste production volume（S4）,water consumption per ten thousand yuan GDP（W6）,disaster area（F7）,electricity consumption per unit GDP（E6）,grain output per unit area（F3）,power generation（E4）,ecological water consumption（W9）,electricity consumption of the whole society（E5）,energy consumption per unit GDP（E3）total energy consumption（E2）,total energy production（E1）,total water resources（W1）,water production modulus（W2）,industrial waste gas emission（S2）,per capita water resources（W3）,fertilizer application rate（F8）,general industrial solid waste comprehensive utilization rate（S5）,SO₂ emission rate（S3）.From the perspective of each system,water consumption per 10,000 yuan GDP（W6）and ecological water consumption（W9）in the water resources subsystem are more important to the coupling coordination degree of Shaanxi Province and each city than other water resources factors.Compared with other energy factors,the power consumption of the whole society（E5）and the power consumption per unit GDP（E6）in the energy subsystem are more important to the coupling coordination degree of Shaanxi Province and each city.In the food subsystem,compared with other grain factors,disaster area（F7）and fertilizer application amount（F8）are more important to the coupling coordination degree of Shaanxi province and each city.In addition,grain yield per unit area（F3）and cultivated land area（F4）are more important to the coupling coordination degree of province and city,respectively.In the environment subsystem,industrial waste gas emission（S2）,SO₂ emission（S3）,general industrial solid waste production（S4）and general industrial solid waste comprehensive utilization（S5）are more important to the coupling coordination degree of Shaanxi Province and its cities than other environmental factors.