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草业学报 ›› 2023, Vol. 32 ›› Issue (5): 106-117.DOI: 10.11686/cyxb2022351

• 研究论文 • 上一篇    

黄河源区不同禁牧年限对垂穗披碱草单根及其根-土复合体力学强度特征的影响

何伟鹏1(), 胡夏嵩1, 刘昌义1(), 李璇1, 李希来2, 付江涛3, 卢海静2, 杨馥铖1, 李国荣1   

  1. 1.青海大学地质工程系,青海 西宁 810016
    2.青海大学农牧学院,青海 西宁 810016
    3.青海大学农林科学院,青海 西宁 810016
  • 收稿日期:2022-08-31 修回日期:2022-10-07 出版日期:2023-05-20 发布日期:2023-03-20
  • 通讯作者: 刘昌义
  • 作者简介:E-mail: 1358128151@qq.com
    何伟鹏(1994-),女,甘肃会宁人,在读硕士。E-mail: 1036762123@qq.com
  • 基金资助:
    国家自然科学基金资助项目(42041006);青海省自然科学基金资助项目(2020-ZJ-906);第二次青藏高原综合科学考察研究项目(2019QZKK0905);青海大学地质资源与地质工程学科硕士点建设项目(41250103)

Impact of the different duration years of grazing prohibition on the mechanical strength characteristics of Elymus nutans roots and its composite systems in the Yellow River source region

Wei-peng HE1(), Xia-song HU1, Chang-yi LIU1(), Xuan LI1, Xi-lai LI2, Jiang-tao FU3, Hai-jing LU2, Fu-cheng YANG1, Guo-rong LI1   

  1. 1.Department of Geological Engineering,Qinghai University,Xining 810016,China
    2.College of Agriculture and Animal Husbandry,Qinghai University,Xining 810016,China
    3.Academy of Agriculture and Forestry,Qinghai University,Xining 810016,China
  • Received:2022-08-31 Revised:2022-10-07 Online:2023-05-20 Published:2023-03-20
  • Contact: Chang-yi LIU

摘要:

为研究黄河源区不同禁牧年限高寒草地植物根系力学特性及根系增强土体抗剪强度贡献特征,本研究以黄河源区河南县地区未禁牧、1 a禁牧、4 a禁牧、10 a禁牧4种工况下的高寒草地植物垂穗披碱草为研究对象,在野外调查、取样及室内单根拉伸试验和根-土复合体直剪试验的基础上,探讨了垂穗披碱草在不同禁牧年限下,单根抗拉力和根-土复合体抗剪强度指标变化特征及其影响因素。结果表明:1~4 a短期禁牧增加了垂穗披碱草生长量指标,而10 a长期禁牧其生长量指标则呈降低的变化特征。随着禁牧年限增加,垂穗披碱草单根抗拉力呈先增大后降低的变化规律,1和4 a禁牧单根抗拉力较未禁牧增幅分别为15.9%、14.8%;垂穗披碱草单根抗拉强度、根-土复合体黏聚力均呈降低趋势,其中10 a禁牧垂穗披碱草单根抗拉强度、根-土复合体黏聚力相对于未禁牧降低幅度最大,分别为57.3%、63.5%。进一步研究表明,根-土复合体黏聚力c值与根径、土体密度之间呈显著正相关关系,与含水率之间则呈显著负相关关系,且黏聚力c值随含根量的增加呈先增大后减小的变化规律。研究结果可为高寒地区开展草地退化、水土流失等灾害的有效防治提供理论支撑和实际指导。

关键词: 黄河源区, 不同禁牧年限, 垂穗披碱草, 单根抗拉强度, 根-土复合体, 抗剪强度

Abstract:

The aim of this research was to investigate how the duration years of grazing prohibition affects the mechanical properties of Elymus nutans roots and its root-soil composite systems. The study sites were the grassland with no grazing prohibition (CK) and the grasslands with 1, 4, or 10 years of grazing prohibition in Henan County, which is located in the Yellow River source region. The researchers conducted a set of laboratory-based tests on the tensile properties of roots of E. nutans and direct shear tests on the root-soil composite systemsto quantify the effect of the duration years of grazing prohibition on the mechanical properties of soil. The results showed that a shorter period of grazing prohibition positively affected the growth of E. nutans with the increased growth index, but a longer period had the negative effect with the decreased growth index. With prolonged grazing prohibition, the tensile resistance of the roots initially increased and then decreased, with root tensile resistance increased by 15.9% after 1 year and 14.8% after 4 years of grazing prohibition. Meanwhile, the tensile strength of single roots and the cohesion of root-soil composite systems decreased gradually with prolonged grazing inhibition. The tensile strength and cohesion decreased by 57.3% and 63.5%, respectively, after 10 years of grazing prohibition compared with CK. The cohesion of root-soil composite systems was positively correlated with root diameter and soil natural density and negatively correlated with the soil moisture content. The relationship between cohesion and root content initially became stronger and then weakened with prolonged prohibition of grazing. These results provide theoretical support and practical guidance for the effective prevention and control of grassland degradation, soil erosion, and other forms of environment damage in alpine regions.

Key words: the Yellow River source region, different duration years of grazing prohibition, Elymus nutans, tensile strength of single root, root-soil composite systems, shear strength