中文摘要：

利用室内模拟降雨试验,定量研究在15°坡度和60,90,120,150mm/h降雨强度下,茵陈蒿（Artemisia capillaris）不同分布格局对坡面流阻力（Darcy-Weisbach阻力系数,f）的影响。结果表明：由于植被格局的阻滞作用,相对于裸地坡面,不同格局坡面流阻力系数明显增大,平均阻力系数是裸坡的1.25∽13.13倍;带状格局（BP）、棋盘状格局（CP）和小斑块格局（XP）增强坡面流阻力的作用显著高于长条状格局（LP）。剪除地上部分后,根系作用坡面阻力系数显著降低,约为裸坡的0.75∽3.78倍。裸坡平均阻力系数随雨强增大呈减小趋势,完整植被格局和根系作用坡面相对阻力系数（与裸坡阻力系数比值）随雨强增大呈指数函数增大。阻力系数与水流雷诺数的关系可用幂函数表示;阻力系数与坡面侵蚀速率呈极显著幂函数关系。

英文摘要：

Laboratory-simulated rainfall experiments were conducted on 15° slopes to quantify the effects of patchy distributed Arternisia capillaris on Darcy-Weisbach friction coefficient （f）. Different intensities of 60, 90, 120, 150 mm/h were applied on a bare plot （CK） and four different patched patterns： A checker- board pattern （CP）, a banded pattern perpendicular to the slope direction （BP）, a single long strip parallel to slope direction （LP）, and a pattern with small patches distributed like the letter ‘X’ （XP）. Each plot under- went two sets of experiments, intact plant and root plots （the above-ground parts were removed）. Results showed that A. capillaris patterns could effectively retard overland flow. Mean f for patterned treatments was 1.25--13.13 times of that for CK. BP, CP, and XP performed more effectively than LP in increasing hydraulic roughness. The removal of grass shoots significantly reduced f with the values being 0.75--3.78 times of that for CK. A negative relationship between mean f for the bare plot and rainfall intensity was obtained, whereas for grass patterned plots fr（mean f in patterned plots divided by that for CK） increased ex- ponentially with rainfall intensity. The f - Re relation was best fitted by a power function. Soil erosion rate could be well described using f by a power-law relationship.