Spatial And Temporal Variation Of Soil Conservation Services In Jing River Basin And The Influencing Factors

The Loess Plateau is the most seriously eroded area in China.How to prevent and effectively deal with the soil erosion is a key scientific problem,which is urgent to be solved at present.As one of the most important regulation services provided by ecosystem,soil conservation service plays an irreplaceable role in preventing regional erosion and maintaining ecological security.However,previous studies mostly use USLE model or RUSLE model as a calculation tool,lack of mechanism research.Hence,this paper takes the Jinghe River Basin in the hinterland of the Loess Plateau as a study area and carries out three research contents.Firstly,based on the Soil and Water Assessment Tool(SWAT)model with certain mechanism,the spatial and temporal variation of soil conservation services is studied.Secondly,the Geographic Detector model is utilized to analyse the influencing factors of soil conservation services.Finally,this paper attempts to evaluate the land suitability from the perspective of soil conservation,in order to provide scientific reference for soil erosion control in the basin.The main research conclusions are as follows:(1)From the perspective of spatial and temporal variation of soil conservation services,the interannual variation of soil conservation services(2000-2018)shows no significant increase trend,but there are significant regional differences in spatial distribution.In terms of time,the interannual variation of soil conservation is mainly related to annual rainfall.Spatially,the soil conservation intensity in the west of the basin is the highest,higher than 130t/ha.The soil conservation intensity in the east is higher,between 50t/ha and 100t/ha,while the soil conservation intensity in the north,middle and south of the basin is lower than 30t/ha.(2)From the perspective of influencing factors,the spatial variation of soil conservation in the basin is dominated by natural factors,and the combined effects of natural factors and human factors can not be ignored.Slope is the primary factor affecting the spatial variation of soil conservation,followed by annual rainfall,annual maximum rainfall intensity of 3h and NDVI.Compared with the influence of single factor,the two-factor interaction will enhance the influence on soil conservation services,the largest one is "slope ∩ land use type",the second one is "slope ∩ NDVI",and the following one is "elevation ∩ slope" and "slope ∩ soil erosibility"(The symbol "∩" means interaction).(3)According to the analysis of land suitability based on soil conservation,the proportion of long-term unsuitable(reconstruction)area and optimal(maintenance)area is the smallest,the proportion of gradually deteriorating(protection)area is small,while that of long-term less suitable(restoration)area and improved(optimization)area is the largest.Reconstruction,restoration and protection areas are the difficult areas of ecological restoration at present,the effect of Grain for Green Project(GFGP)is not very effective or the function of soil conservation is deteriorating,and the way of land use in these areas is not conducive to soil conservation,in addition to optimizing land use,it is necessary to take soil and water conservation engineering measures.