Grass hedges are widely applied on sloping croplands as a low-cost measure to reduce soil and nutrition
loss. Therefore, it is important to understand the role of hedgerows in runoff and sediment processes. In
this study, 36 field runoff simulation experiments were conducted in the red soil region of China to
determine flow hydraulics and soil loss processes under 12 different hedgerow conditions. Specifically,
two types of hedgerow widths (two-row and three-row) were planted for each of three species of
vegetation (Bahia grass (Paspalum notatum), Vetiver (Vetiveria nigritana) and Daylily (Hemerocallis fulva)),
and these plots were tested both before and after the removal of the grass stems. Grass stems played an
important role in decreasing the flow velocity and filtering sediment. For the three selected vegetation
types, the final flow velocities (V3) were ranked in the following order: Bahia grass (0.12 m/s) < Vetiver
(0.17 m/s) < Daylily (0.19 m/s). There was no significant difference between the three grass species in
trapping sediment under the condition of this study. A comparison between the two different hedgerow
widths revealed that the three-row hedges were more effective (decrease ratio >30%) than the two-row
hedges (decrease ratio