降雨类型对砒砂岩区不同土地利用类型坡面产流产沙的影响OA

[Objective]The characteristics of slope runoff and sediment yield of different land use types under natural rainfall conditions in the Pisha sandstone area were explored,in order to provide theoretical and data support for the prevention and control of soil erosion and the comprehensive ecological management of watersheds in this area.[Methods]Taking the small watershed of the Pisha sandstone area in Yijinhuoluo Banner of Inner Mongolia as a study area,based on the observation data of natural rainfall runoff and sediment yield in this area from 2018 to 2023,the rainfall types in this area were classified,the relationship between natural rainfall characteristics and runoff and sediment yield of different land use types was analyzed,and the runoff and sediment yield models of different land use types were established based on rainfall characteristics and slope gradient.[Results]① The rainfall types were classified into three categories.Type Ⅰ rainfall was short-duration moderate rainfall,which was the dominant rainfall type in the study area,accounting for 80.6％of the total rainfall events.Type Ⅱ rainfall was medium-duration heavy rainfall,with a relatively low frequency,accounting for 18.6％of the total rainfall events.Type Ⅲ rainfall was long-duration moderate rainfall,with the lowest frequency,accounting for 0.8％of the total rainfall events.Type Ⅰ and Type Ⅱ rainfall accounted for 39％and 40％of the total slope runoff in the study area,respectively,serving as the main sources of slope runoff.Type Ⅰ rainfall accounted for 81％of the total slope sediment yield in the study area,which was the main source of slope sediment yield.② Under different rainfall types,the sediment yield patterns on 5° and 10° slopes followed the overall order of Type Ⅰ rainfall>Type Ⅱ rainfall>Type Ⅲ rainfall,while the runoff patterns followed the order of Type Ⅱrainfall>Type Ⅰ rainfall>Type III rainfall.The runoff and sediment yield patterns on a 15° slope both followed the order of Type I rainfall>Type Ⅱ rainfall>Type Ⅲ rainfall.For different land use types,the slope runoff and sediment yield patterns of different land types ranked as bare land>cultivated land>grassland>forest land.[Conclusion]The interaction between land use type and slope gradient was the main factor affecting the runoff yield of Type Ⅰ rainfall.The single factor and interaction of land use type and slope gradient both had an effect on runoff and sediment yield under Type Ⅱ rainfall.Land use type was the main factor affecting runoff under Type Ⅲ rainfall.The established models of rainfall and corresponding runoff and sediment yield of different land use types can be applied to soil erosion simulation studies for different land use types in Pisha sandstone area.