海涂围垦区盐碱粉壤土坡面径流剥蚀过程影响试验

Study on the soil detachment process for saline-alkali silty loam slopes in a coastal reclamation area

为探讨盐碱土边坡径流-侵蚀过程规律,通过人工模拟土槽径流冲刷试验定量分析坡度和上方来水流量对海涂围垦区盐碱粉壤土边坡径流剥蚀过程的影响。试验结果表明:上方来水流量和坡度对径流剥蚀速率均有显著正效应且互相制约,剥蚀速率与坡度和径流量存在幂指数函数关系;坡面单宽径流能耗随坡度和上方来水流量的增大均显著增大(P<0.01),单宽径流能耗ew与上方来水流量q、坡度θ存在幂指数函数关系;在坡度5°~15°条件下,临界单宽径流能耗为15~40 J/(h·m),而在高坡度20°~40°条件下,临界单宽径流能耗接近零;剥蚀速率与单宽径流能耗之间存在显著线性关系(R2=0.82),海涂盐碱粉壤土边坡只需较小径流能耗即可剥蚀表层土壤。

In order to study the runoff-erosion process of saline-alkali silty loam slopes in a coastal reclamation area,a series of runoff scouring experiments were conducted to investigate the effects of slope gradient and upstream inflow on the soil detachment process.The results showed that the slope gradient and upstream inflow both had positive effects on the detachment rate but their effects were mutually restricted.The relationships between soil detachment rate,inflow scouring rate and slope gradient can be expressed by a power exponential function.The runoff energy consumption of unit width increased significantly with the increasing of upstream inflow rate and slope gradient(P<0.01).In addition,the relationships between the runoff energy consumption of unit width ew,upstream inflow rate q and slope gradientθcan also be expressed by the power exponential function.The critical runoff energy consumption of unit width was 15~40 J/(h·m)for slopes between 5°and 15°,while it was zero for slopes between 20°and 40°.There was significant linear relationship between the soil detachment rate and the runoff energy consumption of unit width and the relationship can be expressed by the following function:R2=0.82.Soil detachment started when the runoff energy consumption of unit width was very small for saline-alkali soil slopes in the coastal reclamation area.