Root Tensile Resistance of Selected Pennisetum Species and Shear Strength of Root-Permeated Soil

Table 5

Summary of the shear strength parameters and biomass of different planted soils at different values of normal pressure.

Species studied	Normal pressure (kPa)	Max. shear stress (kPa)	Average biomass (g)	Cohesive value c (kPa)	Friction angle θ (°)
PPl	10	11.3	0.146	7.5	21.3
	20	15.5
	30	19.0
PPd	10	7.8	0.058	6.1	12.5
	20	11.2
	30	12.3
Control	10	6.4	NA^∗	4.2	10.7
	20	8.4
	30	11.5

^∗NA = not available (no plant).