Simulation And Analysis Of Soil Conservation Service Flow In The Ecosystem Of Jinghe River Basin

Simulation of the spatial flow of ecosystem services can clarify the supply and demand area of ecosystem services and their mutual feedback,which is important for the formulation of basin ecological environmental policies.At present,there are not many studies on the ecosystem services flow.The paper takes the Jinghe River Basin in the Loess Plateau as the study area,and takes soil conservation services as the object to carry out the simulation and analysis of the ecosystem service flow.Based on the Soil and Water Assessment Tool(SWAT),the paper quantitatively evaluates the soil conservation services in the Jinghe River Basin from 2000-2018,and divides them into three categories:sediment reduction service,soil fertility protection service,and land waste reduction service.On this basis,the paper attempts to carry out the description of the spatial flow path of the soil conservation services at the scale of "slope-channel-sub-basin" and the expression of the flow amount,and finally analyzes the benefits of the soil conservation service flows.The main conclusions are as follows:(1)Temporal and spatial distribution characteristics of the supply and demand of soil conservation services:during the study period,there is a strong correspondence between the supply and demand of soil conservation services and rainfall in the Jinghe River Basin,and the spatial distribution of the supply and demand of soil conservation services are similar.During the study period,the monthly supply amount of soil conservation services of the basin had a strong correspondence with the monthly rainfall.Although there are seasonal fluctuations,the overall trend of supply of soil conservation services is increasing.And there is a strong correspondence between monthly demand amount of soil conservation services and monthly rainfall.Although there are seasonal fluctuations,overall trend of the demand of soil conservation services is decreasing.On the other hand,spatially,areas with high supply amount of soil conservation services,except for the Ganhe sub-basin,basically coincide with areas with high demand amount of soil conservation services.(2)Temporal and spatial distribution characteristics of the state of surplus and loss of soil conservation services:the surplus and loss status of soil conservation services in each sub-basin is obviously restricted by land-use types and topography.Under the same terrain,areas with good vegetation coverage,such as Hongyanhe sub-basin,the surplus months of soil conservation services accounted for 78%of the total months.And areas with poor vegetation coverage,such as Malianhe sub-basin in the north of the basin,the months of loss soil conservation services accounted for 64%of the total months.In terms of administrative divisions,the surplus area for soil conservation services is mainly located in Huanxian,Xifeng and so on with medium-high vegetation coverage and slight terrain fragmentation.(3)Analysis on the temporal and spatial characteristics of soil conservation services composition:The spatiotemporal characteristics of the composition types of soil conservation services such as sediment reduction service,soil fertility protection services,and land waste reduction service have common characteristics From the perspective of monthly changes,the three parts of soil conservation services all show a trend of increasing volatility.On the spatial,the three parts of soil conservation services all show changes with vegetation and topography.The amount of the three types of soil conservation services are high in areas with good vegetation coverage and flat terrain and low in poor vegetation coverage and large terrain undulations.(4)Analysis of the temporal and spatial characteristics of soil conservation service flows:This paper basically realizes the path simulation of the sediment reduction service flow at different spatial scales.By constructing a model for estimating the benefit value within and outside the basin,both of the flow amount of the sediment reduction service flow in the Jinghe River Basin and the benefit value outside the basin are calculated,and they are equal.This study is a useful exploration for the study of ecosystem service flows in the watershed of the Loess Plateau in China,and the results of the study are reasonable.