摘要
植物根系对提高土壤抗侵蚀能力起着最主要的作用。为探究根系对三峡水库消落带土壤抗剪性能的影响,以典型草本植物狗牙根及其根土复合体为研究对象,利用原状土和重塑土、采用直剪试验和三轴试验2种方法,揭示根系形态特征、含根量以及布根方式对土壤抗剪性能的影响。结果表明:1)内摩擦角、黏聚力与根系形态特征呈对数正相关;各形态指标对土壤抗剪性能的影响程度依次为:根表面积密度>根体积密度>根长密度>根质量密度>根径。2)根系含量与土壤抗剪性能呈正相关。含根量分别为0.9、0.6和0.3 mg/cm^(3)的根土复合体抗剪强度依次比素土提高14.54%~49.56%、9.09%~35.82%和3.80%~17.58%;内摩擦角依次提高13.95%、13.07%和1.98%;黏聚力依次提高29.37%、24.48%和15.34%。3)交叉布根下土壤抗剪性能最强,与垂直布根、水平布根相比,交叉布根的抗剪强度依次提高4.22%~16.95%和11.45%~32.61%;黏聚力依次提高15.61%和16.09%;最大应力值依次提高3.78%~34.18%和36.86%~41.44%。研究结果可为三峡水库消落带固土护岸的物种筛选、水土保持生态建设以及水库岸线管理等提供参考。
[Background]Plant roots play the most important role in improving soil erosion resistance.Affected by the fluctuation of water level,the root-soil composite in the water-level fluctuation zone of the Three Gorges Reservoir undergoes alternating cycles of dry and wet,and the effect of its roots on soil shear resistance is weakening.The purpose of this study is to explore the effect of roots on soil shear resistance in the water-level fluctuation zone of the Three Gorges Reservoir.[Methods]The water-level fluctuation zone of the Three Gorges Reservoir at an elevation of 165 m was selected as the study area,and the typical herb Cynodon dactylon and its root-soil composite were sampled during the period of vigorous vegetation.Direct shear tests and triaxial tests were conducted on undisturbed soil and remolded soil,and the internal friction angle and cohesion of soil were obtained.The effects of root morphological characteristics,root content and root layouts on soil shear resistance were discussed by regression analysis and principal component analysis.[Results]1)The internal friction angle has a significant linear positive correlation with root length density,and increases logarithmically with the increase of root surface area density and root volume density.There is a significant logarithmic positive correlation between cohesion and root morphological characteristics.The influence degree of root morphology index on soil shear resistance is as follows:Root surface area density>root volume density>root length density>root weight density>root diameter.2)Compared with rootless soil,the shear strength of root-soil composites with root contents of 0.9,0.6 and 0.3 mg/cm^(3)increase by 14.54%-49.56%,9.09%-35.82%and 3.80%-17.58%.The internal friction angle increases by 13.95%,13.07%and 1.98%,respectively.The cohesion increases by 29.37%,24.48%and 15.34%,respectively.3)Compared with vertical and horizontal layouts,the shear strength of cross layout increases by 4.22%-16.95%and 11.45%-32.61%respectively.Cohesion increases by
作者
郑晓岚
鲍玉海
贺秀斌
谢航宇
禹妍彤
王英培
ZHENG Xiaolan;BAO Yuhai;HE Xiubin;XIE Hangyu;YU Yantong;WANG Yingpei(Key Laboratory of Mountain Supergene Process and Ecological Regulation,Institute of Mountain Hazards and Environment,Chinese Academy of Science,610041,Chengdu,China;University of Chinese Academy of Science,100049,Beijing,China;Agriculture and Rural Committee of Chongqing Dazu District,402360,Chongqing,China)
出处
《中国水土保持科学》
CSCD
北大核心
2024年第4期41-50,共10页
Science of Soil and Water Conservation
基金
国家自然科学基金长江水科学研究联合基金“长江上游水库消落带土壤侵蚀机理及其生态利用模式”(U2040207)
四川省科技计划重点研发项目“大型水库消落带土壤植被演变机理与植被恢复技术研究”(2022YFS0471)
国家自然科学基金“三峡水库消落带草本植物根系形态结构变化及土壤抗蚀性能响应”(41977075)。
关键词
植物根系
根土复合体
土壤抗剪性能
消落带
三峡水库
plant roots
root-soil composite
soil shear resistance
water-level fluctuation zone
Three Gorges Reservoir
