| Water and soil resources are important natural factors for the sustainable development of ecological environment,and have a vital influence on the long-term development of human society.As an independent ecohydrological unit in the ecologically fragile area of the Loess Plateau,the upper Fenhe River is the water source and ecological barrier areas of Taiyuan City,and its ecosystem is of great significance to the sustainable development of the ecological environment.With the rapid development of social economy,the ecological functions of the upper Fenhe River have been declining,and its role in water conservation and soil conservation has not been given full play.Thus the regional sustainable development has been put in severe threats.In this paper,the upper Fenhe River is taken as the research area to carry out the research on the service function and ecological carrying capacity of water and soil resources.The universal soil loss equation and water balance method are adopted to quantitatively analyze the spatio-temporal changes of soil erosion and water conservation service in the basin,and to quantitatively evaluate the coordinated coupling between the ecological carrying capacity of water and soil resources and the two.And the purpose is to improve the rational utilization of water and soil resources in the upper Fenhe River.Collecting meteorological data,water and soil resources utilization data,rainfall and runoff and other measured data in 2000,2008 and 2015,we evaluated the service function of soil erosion and water conservation in the upper Fenhe River.Integrating economy,society and population and other factors,we based DPSIR model and established an evaluation index system of regional carrying capacity of water and soil resources.Therefore,we can quantitatively analyze regional carrying capacity of water and soil resources.Finally,analyzing service function of water and soil resources in the upper reaches of the Fenhe River and discussing the bearing capacity coupling relation through coordination and coupling degree,we put forward suggestions and countermeasures for the rational utilization of water and soil resources in the upper Fenhe River.The main results are as follows:(1)The total amount of soil erosion in the upper Fenhe River continued to decrease in 2000,2008 and 2015.In 2008,it was 8.04% lower than that in 2000,and in 2015,it was 33.44% lower than that in 2008.(2)The total amount of water conservation in the upper Fenhe River increased first and then decreased in 2000,2008 and 2015.It increased by 40% in 2008 compared with the water conservation in 2000,but decreased by 25% in 2015 compared with the situation in 2008.(3)In 2000,2008 and 2015,the carrying capacity of water and soil resources in the upper Fenhe River showed a trend of rising first and then declining as a whole.The comprehensive level of water and soil resources carrying capacity was the highest in 2008,up 13% from 2000.The year-on-year growth in 2015 was up about 8% from 2000.(4)In 2000,2008 and 2015,the coordination and coupling degree between water and soil resources service function and their bearing capacity in the southern part of the research area were relatively high,which mainly concentrated in Taiyuan City,Loufan County,Gujiao City and Yangqu County.The main conclusions are as follows:(1)In the northern areas of the whole research area,soil erosion modulus first rose and then fell,while in the southern areas it fell first and then rose.During the whole study period,the soil erosion modulus in the study area decreased significantly,which indicates that the benefits of soil and water conservation measures in the upper Fenhe River are significant.(2)Water conservation in the southern part of the research area which mainly covers the urban area of Taiyuan City,Yangqu County,Loufan County and Gujiao City and so on,showed a steady upward trend in the three periods while some fluctuations of water conservation could be seen in some cities and counties in the northern part of the research area.(3)The carrying capacity of soil and water resources in Yangqu County,Loufan County and Jingle County has been at a higher level in the three periods,which means the sustainable development ability was strong in these regions.However,the carrying capacity of water and soil resources in Gujiao City has been declining all the time,so it is necessary to improve the utilization of water and soil resources and reasonably plan the management direction in the future.(4)That the high degree of coordination and coupling in 2015 changed from a low degree of coordination and coupling in 2000 in Jingle County indicates that the relationship between water and soil resources service function and their bearing capacity in Jingle County has been improved from an uncoordinated development to a highly coordinated development. |
