暴雨条件下土壤结皮和地表糙度对黄土坡耕地产流产沙过程的影响OA

[Objective]This study aims to investigate the effects of soil crust and surface roughness on runoff and sediment yield processes on loess sloping farmland,thereby providing a theoretical basis for optimizing field management of sloping farmland and improving soil erosion control.[Methods]This study simulated four surface conditions of sloping farmland(bare soil,crust,roughness,and crust+roughness)under three slope gradients(5°,10°,and 15°)and two rainfall intensities(40 mm/h and 80 mm/h),and analyzed the resulting patterns of runoff and sediment yield under different surface conditions of sloping farmland.[Results](1)Soil crust significantly shortened the runoff initiation time and reduced the initial rainfall loss(p<0.05),whereas surface roughness had the opposite effect.When the two were combined,their effects tended to counteract each other.(2)During the runoff and sediment yield processes,the rankings of runoff rate,sediment yield rate,and sediment concentration among treatments at the same time interval generally followed the order of crust>bare soil>crust+roughness>roughness on the 5° and 10° slopes.However,on the 15° slope,these parameters for the roughness and crust+roughness treatments increased,approaching or even exceeding those of the bare soil treatment.(3)Under different slope gradients and rainfall intensities,soil crust consistently promoted both runoff and sediment yield.Roughness reduced runoff and sediment yield on 5° and 10° slopes.However,its runoff-reducing effect diminished on 15° slopes,and its sediment-reducing effect virtually disappeared.The crust+roughness treatment exhibited a critical slope gradient(between 10° and 15°)in its influence on runoff and sediment yield.Below this critical slope gradient,the treatment reduced runoff and sediment yield,while above this critical slope gradient,the treatment promoted runoff and sediment yield.[Conclusion]Soil crust and surface roughness interact with each other.For the combined crust+roughness treatment,a critical slope gradient exists between 10° and 15°.Below this threshold,the treatment inhibits runoff and sediment yield,while above it,it promotes both.