Estimation of root cohesion for desert shrub species in the Lower Colorado riparian ecosystem and its potential for streambank stabilization

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

“…In this case, RAR at different soil depth classes (0.05 m) was calculated using the following equation (Formula 2). Although the total number of roots was overestimated using Formula 2, their mean cross-sectional area at a certain depth was underestimated because of the fact that roots cross under a certain angle and their cross-sectional area would be larger (Adhikari et al 2013). Therefore, the overestimation of total number of roots will be somewhat compensated by the underestimation of root cross-sectional areas (De Baets et al 2008).…”

“…Previous studies have revealed the root tensile strength and root diameters following a power relation Tosi 2007;De Baets et al 2008;Burylo et al 2011;Adhikari et al 2013). This well-known relationship reveals that the developed robust fine roots would contribute more to soil strengthening compare with coarse roots per unit root area roots (De Baets et al 2008;Adhikari et al 2013).…”

“…As the soil sheared, an observably additional cohesion was provided by plant roots to increase soil shear strength (Waldron and Dakessian 1981). Thus, the increased soil shear strength caused by roots is treated as an additional cohesion (C r ) (Adhikari et al 2013). The calculation is presented as follows (Formula 4).…”

“…The root tensile strength (T R ) was measured using a manual dynamometer (F. S. = 50 N, accuracy = 0.1% F. S.) and two clamping jaws which employed in a similar investigation (Adhikari et al 2013). One clamping jaw was attached to the end of the dynamometer and the other one was fastened to the pedestal.…”

“…Root reinforcement (or called root cohesion) depends on several essential variables, including root distribution patterns in terms of rooting depth, root number, root diameter, root length density, and root mass density (Wu et al 1979); root morphological structure, such as tap-like roots and fibrous-like roots (Reubens et al 2007;Burylo et al 2011;Adhikari et al 2013); and biomechanics characteristics of roots, such as root tensile strength (Gray and Barker 2004;Mattia et al 2005) and pull-out strength (Stokes et al 1996;Dupuy et al 2005;Norris 2005;Giadrossich et al 2013). Previous studies have revealed the root tensile strength and root diameters following a power relation Tosi 2007;De Baets et al 2008;Burylo et al 2011;Adhikari et al 2013).…”