高级检索

    不同护坡方式下河岸带土壤养分特征与草本植物根系抗拉力学性能

    Soil nutrient content and root tensile properties of herbaceous plants in riparian zone under different slope protection methods

    • 摘要: 河岸带是连接河流生态系统和陆地生态系统的重要桥梁和纽带,利用生态护坡技术对河岸带边坡进行加固有着重大意义。然而目前缺乏不同生态护坡方式对土壤中的养分特征以及植物根系抗拉力学性能影响的具体认识,对不同生态护坡方式进行评价的方法也较为单一。为此,本文对长江河岸带不同生态护坡方式下土壤中的养分浓度进行测定,并分别对优势物种狗牙根(Cynodon dactylon (L.) Pers.)、牛鞭草(Hemarthria altissima (Poir.) Stapf et C. E. Hubb.)和双穗雀稗(Paspalum paspaloides (Michx.) Scribn.)进行室内单根拉伸试验,分析生态护坡方式对土壤养分含量和草本植物根系抗拉力学特性的影响,期望完善生态护坡技术评价体系,为治理河岸带边坡时设置护坡方式提供理论依据。结果表明:(1)钢丝网石笼护坡下土壤中的有机质浓度、全氮浓度、铵态氮浓度和硝态氮浓度分别比混凝土构件工程护坡大56.27%、64.29%、133.98%和95.20%。(2)三种植物根系的最大抗拉力、最大抗拉强度和弹性模量均与根系直径符合幂函数关系,最大抗拉力随着根系直径的增加而增加,最大抗拉强度和弹性模量随着根系直径的增加而减小,且抗拉力学性能表现为:狗牙根>牛鞭草>双穗雀稗。(3)三种植物根系在混凝土构件工程护坡下的最大抗拉力、最大抗拉强度和弹性模量都高于钢丝网石笼护坡。研究结果阐明了生态护坡方式对河岸带土壤养分含量和草本植物根系抗拉力学性能的影响,为治理河岸带合理选择护坡植物和设置生态护坡方式提供理论依据。

       

      Abstract: Riparian zone is an important bridge and link between river ecosystem and terrestrial ecosystem. It is of great significance to reinforce the slope of riparian zone by using ecological slope protection technology. However, there was a lack of specific understanding of the effects of different ecological slope protection methods on soil nutrient content and tensile properties of plant roots, and the evaluation methods of different ecological slope protection methods were relatively simple. Therefore, this paper measured the concentration of nutrients in soil under different ecological slope protection modes in the riparian zone of the Yangtze River, and conducted indoor single root tensile tests on dominant species C. dactylon, H. altissima and P. paspaloides respectively. The effects of ecological slope protection methods on soil nutrient content and tensile mechanical properties of herbaceous plant roots were analysed. They were expected to improve the evaluation system of ecological slope protection technology and provide a theoretical basis for setting up slope protection methods when controlling riparian slopes. The results showed that: (1) The soil organic matter concentration, total nitrogen concentration, ammonium nitrogen concentration and nitrate nitrogen concentration under the slope protection with steel mesh and stone cage were 56.27 %, 64.29 %, 133.98 % and 95.20 % higher than those under the slope protection with concrete members. (2) The maximum tensile resistance, maximum tensile strength and elastic modulus of roots of the three plants were all in power function relationship with root diameter. The maximum tensile resistance increased with the increase of root diameter, and the maximum tensile strength and elastic modulus decreased with the increase of root diameter. The tensile mechanical properties were as follows: C. dactylon > H. altissima > P. paspaloides. (3) The maximum tensile resistance, maximum tensile strength and elastic modulus of the three plant roots under the slope protection of concrete component engineering were higher than those under the slope protection of steel mesh cage. The results of the study clarified the effects of ecological slope protection methods on soil nutrient content and tensile properties of herbaceous plant roots in riparian zones, and provided a theoretical basis for the rational selection of slope protection plants and the setting of ecological slope protection methods in riparian zones.

       

    /

    返回文章
    返回