生态学报2024，Vol.44Issue(15)：6841-6853,13.DOI:10.20103/j.stxb.202401030015
草地植被冠层与根系对黄土坡面侵蚀过程的影响
Effects of canopy and root of grassland vegetation on erosion processes of the Loess Plateau
摘要
Abstract
Grassland vegetation can effectively control slope erosion.However,the regulation effects of different grassland vegetation types and their canopies and roots on slope erosion have not been systematically studied.In this study,artificial simulated rainfall experiments were used to quantitatively study the effects of canopies and roots of alfalfa(Medicago sativa)and ryegrass(Lolium perenne)on soil erosion processes of loess slope,hydrodynamic parameters and soil erosion resistance characteristics under different rainfall intensities.The results showed that the average runoff reduction benefit of alfalfa and ryegrass was 17.65％and 9.8％,and the sediment reduction benefit was 63.86％and 69.88％,respectively,compared to bare slope.The average relative contribution rates of the roots to the benefit of the runoff reduction and sediment reduction were higher than those of the canopies under different rainfall intensities.And the relative contribution rate of the roots to the benefit of the sediment reduction increased with the increase of rainfall intensity.Grassland vegetation regulated erosion dynamics mainly by reducing flow velocity and increasing slope resistance.The effect of the roots in decreasing flow velocity was slightly greater than that of the canopies,but the effect of the roots in increasing slope resistance was obviously smaller than that of the canopies.The effects of ryegrass in decreasing flow velocity and increasing slope resistance were higher than those of the same part of alfalfa.A power function y=αxβ fitted better in flow shear stress and slope erosion rate relationship.The coefficient α of the power function can be interpreted as the modulus of soil erosion caused by unit flow shear stress,and can be used as an index to reflect soil erosion resistance.The reduction benefit of the coefficient α under the action of the roots was much higher than that of the canopies,which reflected that the roots had significantly enhanced soil erosion resistance compared to the canopies.The enhancement of soil erosion resistance was mainly attributed to the improvement of soil properties in the topsoil layer by the roots of grassland vegetation.In this study,bulk density of grassland vegetation plots decreased significantly,and soil organic matter,soil porosity,saturated hydraulic conductivity,mean weight diameter of soil aggregates and shear strength of them increased obviously compared to bare slope plot.The soil properties of the grassland vegetation plots were obviously improved,which consequently enhanced the soil erosion resistance.The roots of grassland vegetation improved the soil properties in the topsoil layer,and its ability to enhance soil erosion resistance was much greater than that of the canopies.Furthermore,the ability of ryegrass with fibrous root system to strengthen soil erosion resistance was better than that of alfalfa with taproot system.The study revealed that grassland vegetation could control slope erosion processes through the joint action of canopies and roots to regulate erosion dynamics and soil erosion resistance,simultaneously.The roots of grassland vegetation played a leading role in controlling slope erosion,and grassland vegetation with fibrous root system had the best effect on the control of loess slope erosion.The results can provide scientific support for the study of soil erosion processes of grassland and the construction and management of grassland on the Loess Plateau.关键词
土壤侵蚀过程/水动力学参数/土壤抗侵蚀能力/冠层/根系/黄土高原Key words
soil erosion processes/hydrodynamic parameters/soil erosion resistance/canopy layer/root/the Loess Plateau引用本文复制引用
陈浩,王豆豆,崔钦凯,王博,刘俊娥,李占斌..草地植被冠层与根系对黄土坡面侵蚀过程的影响[J].生态学报,2024,44(15):6841-6853,13.基金项目
国家自然科学基金项目(42107359) （42107359）
中国博士后科学基金项目(2022MD713800) （2022MD713800）
延安市高层次人才专项项目(2019-16) （2019-16）
延安大学科研计划资助项目(YDBK2019-63) （YDBK2019-63）
