Flow velocity is one of the most significant hydraulic parameters directly connected to sediment transport-deposition processes. Four soils were collected from north to south of the Loess Plateau, namely Sandy Loess (SL), Loessial Soil (LS), Heilu Soil (HS) and Anthrosol Soil (AS), to examine the impacts of soil property on mean flow velocity in both interrill and rill flows under different simulated rainfall experiments. The mean velocity of interrill flow (MVIF) followed the order of LS > HS ≈ AS > SL at 90 mm h⁻¹ rainfall intensity and LS > HS > AS > SL at 120 mm h⁻¹ rainfall intensity. The mean velocity of rill flow (MVRF) decreased as LS ≈ HS > AS at 90 mm h⁻¹ and LS ≈ HS > AS > SL at 120 mm h⁻¹. The order of MVIF and MVRF on four soil slopes is determined by the relations of runoff discharge, Darcy-Weisbach friction factor in interrill area (f_I) and rills (f_R), which are closely related to soil properties. Soil properties also changed the effects of rainfall intensity on flow velocities in different erosion stages, resulting in the increasing trend of MVIF on SL, HS and AS slopes and the decreasing trend of MVIF on LS slope with the increase of rainfall intensity. Moreover, soil properties may change the variations of MVIF and MVRF with the increase of slope gradient, by altering the relations of sealing progress and slope effect. The slope effect determined the increasing trend of MVIF with the increase of slope gradients. However, the sealing progress may offset the slope effect and cause the decrease of MVIF on the critical slopes, and the critical slope decreased from the north (20° and 25°) to the south (15°). The equal roles of rill bed roughness and slope effect caused the unchanged of MVRF on LS and HS slopes, while rill bed roughness dominated the fluctuations of MVRF on SL and AS slopes.

流速是直接与沉积物输送-沉积过程相关的最重要的水力参数之一。黄土高原从北到南共收集了四种土壤，分别是沙土黄土（SL），黄土土（LS），黑鹿土（HS）和炭疽土（AS），以研究土壤性质对黄土高原平均流速的影响。在不同的模拟降雨实验中，钻探和钻探流量都不同。在90 mm h ^-1降雨强度下，钻进间平均流速（MVIF）遵循LS> HS≈AS > SL的顺序，在120 mm h ^-1降雨强度下钻进的平均速度为LS> HS> AS> SL 。细沟流（平均速度MVRF）作为LS≈HS在90毫米高降低> AS ^-1，在120毫米高LS≈HS> AS> SL^-1。MVIF和MVRF在四个土质边坡上的顺序由径流流量，钻间区（f _I）和小溪（f _R）中的达西-魏斯巴赫摩擦系数之间的关系确定，这与土壤特性密切相关。土壤性质也改变降雨强度的影响在不同的侵蚀阶段的流速，从而导致增加的趋势MVIF上SL，HS和AS斜坡和下降的趋势MVIF上LS斜率与降雨强度的增加。此外，土壤性质可能会改变MVIF和MVRF的变化随着边坡坡度的增加，通过改变封闭进度与边坡效果的关系。斜率效应决定了MVIF随斜率梯度的增加而增加的趋势。然而，密封的进展可能抵消了边坡效应，并导致临界边坡的MVIF降低，临界坡度从北（20°和25°）向南（15°）降低。钻孔床粗糙度和边坡效应的相等作用导致LS和HS斜坡上的MVRF保持不变，而钻孔床粗糙度主导SL和AS斜坡上的MVRF的波动。