Journal of Mountain Science

, Volume 13, Issue 3, pp 508–521

Estimation of soil reinforcement by the roots of four post-dam prevailing grass species in the riparian zone of Three Gorges Reservoir, China

  • Rong-hua Zhong
  • Xiu-bin He
  • Yu-hai Bao
  • Qiang Tang
  • Jin-zhang Gao
  • Dan-dan Yan
  • Ming-feng Wang
  • Yu Li
Article

DOI: 10.1007/s11629-014-3397-2

Cite this article as:
Zhong, R., He, X., Bao, Y. et al. J. Mt. Sci. (2016) 13: 508. doi:10.1007/s11629-014-3397-2
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Abstract

Soil erosion and bank degradation is a major post-dam concern regarding the riparian zone of the Three Gorges Reservoir. The development and succession of vegetation is a main countermeasure, especially to enhance bank stability and mitigate soil erosion by the root system. In this study, the roots of four prevailing grass species, namely, Cynodon dactylon, Hemarthria altissima, Hemarthria compressa, and Paspalum paspaloides, in the riparian zone were investigated in relation to additional soil cohesion. Roots were sampled using a single root auger. Root length density (RLD) and root area ratio (RAR) were measured by using the WinRHIZO image analysis system. Root tensile strength (TR) was performed using a manual dynamometer, and the soil reinforcement caused by the roots was estimated using the simple Wu’s perpendicular model. Results showed that RLD values of the studied species ranged from 0.24 cm/cm3 to 20.89 cm/cm3 at different soil layers, and RLD were significantly greater at 0–10 cm depth in comparison to the deeper soil layers (>10 cm). RAR measurements revealed that on average 0.21% of the reference soil area was occupied by grass roots for all the investigated species. The measured root tensile strength was the highest for P. paspaloides (62.26 MPa) followed by C. dactylon (51.49 MPa), H. compressa (50.66 MPa), and H. altissima (48.81 MPa). Nevertheless, the estimated maximum root reinforcement in this investigation was 22.5 kPa for H. altissima followed by H. compressa (21.1 kPa), P. paspaloides (19.5 kPa), and C. dactylon (15.4 kPa) at 0–5 cm depth soil layer. The root cohesion values estimated for all species were generally distributed at the 0–10 cm depth and decreased with the increment of soil depth. The higher root cohesion associated with H. altissima and H. compressa implies their suitability for revegetation purposes to strengthen the shallow soil in the riparian zone of the Three Gorges Reservoir. Although the soil reinforcement induced by roots is only assessed from indirect indicators, the present results still useful for species selection in the framework of implementing and future vegetation recovery actions in the riparian zone of the Three Gorges Reservoir and similar areas in the Yangtze River Basin.

Keywords

Bank stabilization Root area ratio Root tensile strength Soil reinforcement Riparian zone Three Gorges Reservoir 

Supplementary material

11629_2014_3397_MOESM1_ESM.pdf (142 kb)
Supplementary material, approximately 141 KB.

Copyright information

© Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Rong-hua Zhong
    • 1
    • 2
  • Xiu-bin He
    • 1
  • Yu-hai Bao
    • 1
  • Qiang Tang
    • 3
  • Jin-zhang Gao
    • 1
    • 2
  • Dan-dan Yan
    • 1
    • 2
  • Ming-feng Wang
    • 1
    • 2
  • Yu Li
    • 1
    • 2
  1. 1.Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengduChina
  2. 2.University of Chinese Academy of SciencesBeijingChina
  3. 3.State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental SciencesChinese Academy of SciencesBeijingChina