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

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.