3.3. Runoff volume and sediment yield
Release of sediment was similar for each rainfall event in each individual
treatment. We therefore investigated five rainfall events at the
beginning of June 2012 to study the surface runoff and sediment release
(Fig. 7). The runoff and sediment increased rapidly and linearly under
NC. The load under ST was similar, but the rate of increase was far
less. The sediment release curve under other treatments resembled a
step-shaped increase before reaching a plateau stage, which was in accordance
to the results from strip vegetation covers (Huang et al.,
2013). Once the rainfall stopped, the runoff volume and sediment
yield under all treatments sharply decreased and approached zero.
The time to reach the peak value for both runoff volume and sediment
yield under NC (approximately 45 min) were slightly greater than
those under SMs (around 40 min). The durations of both under NC
(25–30 min) were a bit shorter than those under SMs (30–40 min).
These results indicated that: (i) SMs delayed the commencing of runoff
and sediment, and (ii) SMs extended the time to reach the peak value. In
a special case of ST, the time to reach sediment yield plateau was around
50 min, and the duration of plateau was relative short (approximately
18 min).