Effects of patterned Artemisia capillaris on overland flow velocity under simulated rainfall

Vegetation cover is an important factor for erosion control. Laboratory-simulated rainfall experiments were conducted to quantify the effectiveness of patchy distributed Artemisia capillaris in retarding overland flow velocity. Simulated storms (60, 90, 120, and 150?mm?h-1) were applied on a bare plot (CK) and four different plant patterns, a banded pattern perpendicular to the slope direction (BP), a single long strip parallel to slope direction (LP), small patches distributed like a checkerboard (SP1), and small patches distributed like a letter X (SP2). All treatments had three replicates. Each plot underwent two sets of experiments, intact plant plots and root plots (the above-ground parts were removed, only roots were reserved), respectively. Results showed that flow velocity increased with rainfall intensity, and the lower slope velocity (Vl) was higher than the upper slope velocity (Vu). The removal of grass shoots increased flow velocity. Compared with bare soil plot, intact plants reduced mean flow velocity by 14%60%, whereas the reduction declined to <40% for the root plots. BP and both SP treatments performed more effectively than LP in retarding flow velocity, whereas no significant differences were identified between BP and SP. The contributions of A. capillaris shoots and roots to the reductions in flow velocity under different rainfall intensities were different. The shoots made greater contribution of 53%97% at 60 and 90?mm?h1, and the roots contributed more (51%81%) at 120 and 150?mm?h1. Runoff and sediment rate had significant (p?