辽西薄层土区垂直垄向随机粗糙度的降雨响应与稳糙阈值OA

To investigate the dynamic response law of vertical ridge random roughness(Cr)under the coupling condition of"prolonged drought-rainstorm-thin soil"in the low mountain and hilly area of western Liaoning,four natural rainfalls from June to September 2022 were analyzed,and the Cr values of slope surface under seven soil and water conservation measures were dynamically monitored.Combined with runoff coefficient(R)and soil physical and chemical properties,the response mechanism and stability mechanism of Cr to rainfall were analyzed.The results showed that the Cr value showed a dominant effect of early rain,and the ΔCr before and after the first rainfall was 90.40%.When the rainfall intensity is greater than or equal to 18.82 mm/h,Cr enters the'high rainfall intensity saturation'stage,and its change rate tends to be stable.There was a significant negative correlation between R and Cr only when the rainfall intensity was greater than or equal 18.82 mm/h(p<0.01),and the mechanism could be attributed to the filling effect of runoff.Soil clay content was always significantly negatively correlated with Cr(p<0.01).The inhibitory roughness effect of soil organic matter(SOM)decreased with the extension of rainfall duration,while the inhibitory roughness effect of soil bulk density(BD)increased with the increase of cumulative rainfall,forming a dynamic complementary barrier effect.Because of the combination characteristics of'high clay,high organic matter,low bulk density and low runoff coefficient',the Cr baseline value and ΔCr of forest land and fruit tree terrace are the lowest,showing the best stability.The research conclusions provide a theoretical basis for soil erosion prediction and optimization of soil and water conservation measures in thin soil areas.