Background Riparian zone is an important bridge and link between river ecosystem and terrestrial ecosystem. Slopes of riparian zone are prone to slope instability or soil erosion under the effect of rainfall or river water scouring. Therefore, 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-protecting methods were relatively simple.

Methods Therefore, this paper measured the content of nutrients in soil of the Yangtze River riparian zone under two ecological slope-protecting methods: concrete component engineering and steel mesh gabions, and conducted indoor single root tensile tests on dominant species Cynodon dactylon, Hemarthria altissima and Paspalum paspaloides respectively. The effects of ecological slope-protecting methods on soil nutrient content and tensile 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-protecting methods when controlling riparian slopes.

Results 1) The soil organic matter concentration, total nitrogen concentration, ammonium nitrogen concentration and nitrate nitrogen concentration under the slope protection with steel mesh gabion were 56.27%, 64.29%, 133.98% and 95.20% higher than those under the slope protection with concrete component engineering. 2) The maximum tensile force, maximum tensile strength and elastic moduli of roots of the three plants were all in power function relationship with root diameter. The maximum tensile force increased with the increase of root diameter, the maximum tensile strength decreased with the increase of root diameter and the elastic moduli decreased with the increase of root diameter. The tensile mechanical properties of three herbaceous plants were as follows: C. dactylon > H. altissima > P. paspaloides. 3) The average maximum tensile force, average maximum tensile strength and average elastic moduli of the three plant roots under the slope protection of concrete component engineering were higher than those under the slope protection of steel mesh gabion.

Conclusions In terms of root growth and tensile mechanical properties, concrete component engineering outperforms steel mesh gabions in riparian zones, offering stronger soil stabilization and slope protection through plant roots. The results of the study clarified the effects of ecological slope-protecting methods on soil nutrient characterization 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-protecting methods in riparian zones.