Interception Effect of Surface Runoff on Different Width Bambusa rigida Keng Riparian Buffer Strips

Using the precipitation,throughfall,stemflow of bamboo river buffer strips at 2008 to calculate canopy interception,measure the max water-holding capacity of forest litter and soil in winter and summer respectively,building simple slope runoff to observe surface runoff on different width buffer strips through 5 m to 40 m. The result show that canopy interception is 315.6 mm and account for 32.4% of precipitation of the whole year,canopy interception increase with precipitation,while canopy interception rate decrease. Selecting 24 groups of precipitation and canopy interception to make function is I=0.7791P0.78. The biomass of bamboo litter is 2.87 t/hm2 and max water-holding capacity is 9.13 t/hm2 which is as 3.2 times as dry weight. Litter interception effect is obviously weaken because of precipitation continuity on times distribution,the interception of litter account for 9.2% of precipitation in fact. The bamboo has a positive effect on soil physical properties,soil bulk density decrease with soil depth and accelerate surface runoff infiltration. The max interception of soil is 497.36 t/hm2. With the increasing width of river buffer strips,surface runoff decrease. The 20 m width river buffer strips could reduce 40.7% runoff and interception rate has no significant change when the buffer strips width continue to incerese.