The measured root mass density of soil samples ranged
from 0.25 to 17.98 kg m-3 with a mean value of 3.96 kg m-3.
The measured root mass varied from 0.07 to 1.79 g with a
mean of 0.47 g. The measured root diameter ranged from
0.10 to 0.96 mm with a mean value of 0.49 mm, and the
manually measured root length ranged from 0.30 to 6.09 m
with a mean value of 1.99 m (table 1). The measured soil
detachment rates related to flow discharge, slope gradient,
and root density. The range of the y-axis values in figure 2
increased with slope gradient from 0.40 to 1.20 kg m-2 s-1.
Comparing the graphs of different slope gradients, it was
clear that soil detachment rates of both the control and
rooted soil samples increased with increasing slope
gradient.
The measured average detachment rates decreased as
root density increased on all four slopes tested in this study.
The mean detachment rate of rooted soil samples decreased
from 0.299 kg m-2 s-1 for the control to 0.074 kg m-2 s-1 for
the pooled samples of all root treatments (table 2). In other
words, the mean detachment rate of rooted soil samples
was only one-fourth that of the control.