2种草本植物根系对崩岗洪积扇土壤分离的影响

Effects of Two Herb Plants Roots on Soil Detachment in Alluvial Fan

为探讨草本植物根系对崩岗洪积扇土壤分离的影响,以宽叶雀稗(Paspalum wettsteinii)和巨菌草(Pennisetumsp.)为研究对象,采用变坡水槽冲刷试验,研究种植草本植物后土壤分离的变化特征及影响因素。结果表明:各土层平均土壤分离速率大小为裸地(69.93g/(s·m2))>宽叶雀稗(57.42g/(s·m2))>巨菌草(43.28g/(s·m2)),且不同植被土壤分离速率均随着土层的加深呈幂函数增加;根长密度是影响土壤分离最重要的根系指标,宽叶雀稗小区土壤分离速率随各根系参数指标的增大呈对数函数下降,而巨菌草区则表现为幂函数下降,体现了不同植被根系构型对土壤分离效应的差异;2种草地土壤分离速率可以用水流剪切力、土壤抗剪强度和根长密度很好的模拟(NSE≥0.90)。研究结果可为崩岗治理措施的配置提供科学依据。

In order to investigate the effects of herbaceous roots on soil detachment in alluvial fan of benggang,Paspalumwettsteinii and Pennisetum sp.were chosen as the research objects,and an experiment was carried out using flow flumes with adjustable slope gradients to analyze the changing characteristics of soil detachment and their influencing factors.The results showed that the soil detachment rates of each soil layer were as follows:Bare land(69.93g/(s·m2))>Paspalumwettsteinii(57.42g/(s·m2))>Pennisetum sp.(43.28g/(s·m2)),and the soil detachment rates increased with the increase of soil depth as a power function.The most important factor to characterize soil detachment was root length density,and the soil detachment rates of Paspalumwettsteinii plot declined as a logarithmic function with all root indexes,while a power function decline was observed for Pennisetum sp.plot,indicating the difference effects of root system configurations on soil detachment.Soil detachment of two kinds of grasslands could be estimated using flow shear stress,soil shear strength,and root length density(NSE≥0.90).The results of this study could provide scientific evidences for the disposition of collapse management measures.