By scouring experiments, the changeable process and characteristics of sediment yield in the hillslope-gully side erosion system with different coverage degrees and spatial locations of grass were studied. Five grass ...By scouring experiments, the changeable process and characteristics of sediment yield in the hillslope-gully side erosion system with different coverage degrees and spatial locations of grass were studied. Five grass coverage degrees of 0, 30%, 50%, 70%, 90%, three spatial locations of grass （upslope, mid-slope, low-slope） and two water inflow rates of 3.2 L/min, 5.2 L/min were applied to a 0.5 by 7 m soil bed in scouring experiments. Results showed that the sediment yield decreased with the increase of grass coverage degree at 3.2 L/min water inflow rate in scouring experiments and the sediment yield with different grass locations on the sloping surface was in the order of upper 〉 middle 〉 lower. At 5.2 L/min water inflow rate, the differences of sediment yield among various grass coverage degrees were increased, whereas the changeable tendency of sediment yield with different grass locations on the whole sloping surface was not very obvious. The proportion of sediment yield from the gully side increased in an exponential relationship with the increase of grass coverage degree When the grass was located on the lower position of hillslope, the influence for accelerating gully erosion is the greatest.展开更多
坡面薄层水流侵蚀不仅造成土壤养分流失,土壤质量恶化,同时对水体污染等环境问题造成一定影响。为了分析上方来水流量对红壤坡面径流侵蚀过程中泥沙的迁移规律及土壤溶质运移特征的影响,本试验利用室内放水冲刷试验,采用3个不同上方来...坡面薄层水流侵蚀不仅造成土壤养分流失,土壤质量恶化,同时对水体污染等环境问题造成一定影响。为了分析上方来水流量对红壤坡面径流侵蚀过程中泥沙的迁移规律及土壤溶质运移特征的影响,本试验利用室内放水冲刷试验,采用3个不同上方来水流量(10 L min-1、15 L min-1、20 L min-1)对第四纪黏土发育红壤坡面径流侵蚀过程中坡面径流泥沙和径流中非吸附性离子(Br-)迁移过程进行了研究。结果表明:不同上方来水条件下,放水初期产流量迅速增大,后期趋于稳定,累积径流量与产流时间成显著的线性关系,10 L min-1、15 L min-1、20 L min-1三种上方来水流量下累积径流量分别为263.2 L、295.1 L、291.04 L;上方来水流量越大,薄层径流冲刷作用越强烈,径流含沙量随时间变化波动越剧烈,累积泥沙量随产流时间呈幂函数变化,15 L min-1、20 L min-1流量下累积泥沙量分别为10 L min-1流量下累积泥沙量的1.42倍、4.25倍;径流Br-浓度随产流时间呈幂函数衰减,反映了土壤溶质随径流迁移量变化主要受水流与土壤接触时间和作用程度的影响。研究表明放水冲刷对土壤侵蚀及溶质运移有重要作用,试验结果对有效预测与控制红壤坡面侵蚀及养分流失具有重要实际意义。展开更多
As vegetation are closely related to soil erosion,hydrodynamic parameter changes under various vegetation pattern conditions can be used as an important basis for the research of the soil erosion mechanism.Through ups...As vegetation are closely related to soil erosion,hydrodynamic parameter changes under various vegetation pattern conditions can be used as an important basis for the research of the soil erosion mechanism.Through upstream water inflow experiments conducted on a loess hillslope,how the vegetation pattern influences the hydrodynamic processes of sediment transport was analyzed.The results show that the placement of a grass strip on the lower upslope can effectively reduce runoff erosion by 69%,relying on the efficiency of regulated hydrodynamic process.The effective location of grass strip for hillslope alleviating erosion is on the lower part of the upslope,mainly due to the grass strip measure used to regulate the hydrodynamic system.As a result,the underlying surface runoff resistance is increased by 5 times,runoff shear stress is decreased by more than 90%,and runoff power decreased by over 92%.The measure greatly separates the scouring energy of surface runoff that acts on the slope soil.Therefore,the use of grass strips effectively decreases the energy of runoff flowing along the slope,eliminating soil erosion to a great extent and thereby achieving a better regulation of hydrodynamic processe.展开更多
基金National Basic Research Program of China,No.2007CB407201National Key Technology R&D Program,No.2006BAB06B01-06Science and Technique Development Foundation of YRIHR,No.200603
文摘By scouring experiments, the changeable process and characteristics of sediment yield in the hillslope-gully side erosion system with different coverage degrees and spatial locations of grass were studied. Five grass coverage degrees of 0, 30%, 50%, 70%, 90%, three spatial locations of grass （upslope, mid-slope, low-slope） and two water inflow rates of 3.2 L/min, 5.2 L/min were applied to a 0.5 by 7 m soil bed in scouring experiments. Results showed that the sediment yield decreased with the increase of grass coverage degree at 3.2 L/min water inflow rate in scouring experiments and the sediment yield with different grass locations on the sloping surface was in the order of upper 〉 middle 〉 lower. At 5.2 L/min water inflow rate, the differences of sediment yield among various grass coverage degrees were increased, whereas the changeable tendency of sediment yield with different grass locations on the whole sloping surface was not very obvious. The proportion of sediment yield from the gully side increased in an exponential relationship with the increase of grass coverage degree When the grass was located on the lower position of hillslope, the influence for accelerating gully erosion is the greatest.
文摘坡面薄层水流侵蚀不仅造成土壤养分流失,土壤质量恶化,同时对水体污染等环境问题造成一定影响。为了分析上方来水流量对红壤坡面径流侵蚀过程中泥沙的迁移规律及土壤溶质运移特征的影响,本试验利用室内放水冲刷试验,采用3个不同上方来水流量(10 L min-1、15 L min-1、20 L min-1)对第四纪黏土发育红壤坡面径流侵蚀过程中坡面径流泥沙和径流中非吸附性离子(Br-)迁移过程进行了研究。结果表明:不同上方来水条件下,放水初期产流量迅速增大,后期趋于稳定,累积径流量与产流时间成显著的线性关系,10 L min-1、15 L min-1、20 L min-1三种上方来水流量下累积径流量分别为263.2 L、295.1 L、291.04 L;上方来水流量越大,薄层径流冲刷作用越强烈,径流含沙量随时间变化波动越剧烈,累积泥沙量随产流时间呈幂函数变化,15 L min-1、20 L min-1流量下累积泥沙量分别为10 L min-1流量下累积泥沙量的1.42倍、4.25倍;径流Br-浓度随产流时间呈幂函数衰减,反映了土壤溶质随径流迁移量变化主要受水流与土壤接触时间和作用程度的影响。研究表明放水冲刷对土壤侵蚀及溶质运移有重要作用,试验结果对有效预测与控制红壤坡面侵蚀及养分流失具有重要实际意义。
基金the National Natural Science Foundation of China(Grant No:42177346,52009103,U2243240)Innovation Capability Support Program of Shaanxi(2019TD-040)Observation and Research Station of Groundwater and Ecology in Yulin,Shaanxi,Ministry of Natural Resources。
文摘As vegetation are closely related to soil erosion,hydrodynamic parameter changes under various vegetation pattern conditions can be used as an important basis for the research of the soil erosion mechanism.Through upstream water inflow experiments conducted on a loess hillslope,how the vegetation pattern influences the hydrodynamic processes of sediment transport was analyzed.The results show that the placement of a grass strip on the lower upslope can effectively reduce runoff erosion by 69%,relying on the efficiency of regulated hydrodynamic process.The effective location of grass strip for hillslope alleviating erosion is on the lower part of the upslope,mainly due to the grass strip measure used to regulate the hydrodynamic system.As a result,the underlying surface runoff resistance is increased by 5 times,runoff shear stress is decreased by more than 90%,and runoff power decreased by over 92%.The measure greatly separates the scouring energy of surface runoff that acts on the slope soil.Therefore,the use of grass strips effectively decreases the energy of runoff flowing along the slope,eliminating soil erosion to a great extent and thereby achieving a better regulation of hydrodynamic processe.
