Research On The Impact Of Drought On Soil Conservation Services In The Context Of Climate Chang

As one of the important ecosystem regulation services,soil conservation services lay the foundation for the improvement and promotion of the quality of the ecological environment.The fragmented topography,loose soils,low rainfall and drought are common in the Jinghe River Basin.The land use are mainly grassland and arable land.The effect of soil and water conservation was poor,coupled with unreasonable human activities,making the ecological environment of the Jinghe River Basin very fragile.Therefore,based on the assessment of meteorological drought,hydrological drought and agricultural drought and soil conservation services in the Jinghe River Basin,this study analyzed the temporal and spatial characteristics of seasonal and annual drought and soil conservation services,and explored the effects of drought on soil conservation.It also predicts the spatiotemporal changes of future drought and its impact on soil conservation services under RCP4.5 and RCP8.5 scenarios.It provides references for regional ecological construction,environmental protection and accelerating sustainable economic development.The main conclusions drawn was as follows:(1)The characteristics of meteorological drought,hydrological drought and agricultural drought in the Jinghe River Basin vary in different time scales.The frequency of drought at the annual scale was higher than that at the seasonal scale.The frequency of light drought was the highest,followed by medium drought and severe drought,and the lowest frequency of special drought.The intensity of seasonal meteorological drought,hydrological drought and agricultural drought varies with seasons,and their trends vary slightly with seasons.The areas with higher drought intensity of annual-scale meteorological drought,hydrological drought and agricultural drought were mostly located in the western and northern parts of the Jinghe River basin.The drought shows a clear trend of wetting.(2)The spatial and temporal differences in soil conservation services in the Jinghe River Basin were large.On the seasonal scale,the soil conservation was the highest in summer,followed by autumn and spring,and the lowest soil conservation was in winter.Spatially,the soil retention in all seasons shows a high distribution in the southwest,south and east.On the annual scale,the total soil conservation service was as follows:arable land>grassland>forest land>construction land>water area>unused land.The spatial distribution shows a trend of "high in the southwest and east and low in the north".(3)The trends of drought and soil conservation services under different future climate scenarios are unstable.On the seasonal scale,the drought intensity changes unsteadily under the RCP4.5 scenario;the intensity of meteorological drought,hydrological drought and agricultural drought increases and then decreases in spring,summer and autumn under the RCP8.5 scenario,while it shows a continuous weakening phenomenon in winter.At the annual scale,the intensity of meteorological drought,hydrological drought and agricultural drought gradually increases under the RCP4.5 scenario;the intensity of meteorological dryness gradually increases,and the intensity of hydrological drought and agricultural drought first increases and then decreases under the RCP8.5 scenario.Compared with 2019,the RCP4.5 scenario shows the most severe decline in soil conservation services overall in summer and autumn,followed by spring and winter,and the opposite for the RCP8.5 scenario on the seasonal scale.On the annual scale soil conservation services are severely reduced,with the most severe decreases in soil conservation services in 2030S and 2050S under the RCP4.5 and RCP8.5 scenarios,followed by 2040S and 2060S.(4)Soil conservation services generally show a decline under the influence of drought,and will be more severely affected by drought in the future.On the seasonal scale,meteorological droughts had the most serious impact on soil conservation services in spring and autumn.Hydrologic drought had the most severe impact on soil conservation services in summer and autumn.Agricultural drought had the most severe impact on soil conservation services in winter and summer;In the future,meteorological drought and hydrological drought will have the most severe impact on soil conservation services in winter and autumn,followed by spring and summer under the RCP4.5 scenario.Agricultural drought will have the most severe impact on soil conservation services in winter and spring,followed by autumn and summer.Meteorological drought and agricultural drought will have the most severe impact on soil conservation services in winter and autumn under the RCP8.5 scenario,followed by spring and summer.Hydrological drought will have the most severe impact on soil conservation services in winter and spring,followed by autumn and summer.On the annual scale,past and future meteorological droughts have the most serious impact on soil conservation services,followed by hydrological droughts and agricultural droughts.