不同宽度硬头黄竹林河岸缓冲带对地表径流的拦截效应

利用2008年河岸缓冲带硬头黄竹人工林的降雨量、穿透降雨量和树干径流量来计算林冠层截留量,并在冬、夏两季分别对林内枯落物和取样土壤测定最大持水能力,建立5m至40m不同缓冲带宽度的简易径流场观测地表径流量.结果表明:全年林冠截留总量为315.6 mm,占全年降水量的32.4%,林冠截留量随着降雨量的增加而增加,但林冠截留率反而减小,选取24组不同雨量级的降雨量(P)与林冠截留量(I)数据进行拟合,方程为:I=0.7791P~(0.78).硬头黄竹林内枯落物生物量为2.87 t/hm~2,其最大持水量为9.13 t/hm~2,是枯落物自身干质量的3.2倍,但由于>10 mm的降雨在时间分布上具有连续性,枯落物对降雨的截留效应明显被削弱.实际截留量只占全年降水量的9.2%.硬头黄竹林对林内土壤物理性质起到了明显的改善作用,土壤容重随着土壤深度的变浅而减小,加快了地表径流的人渗速率,土壤的最大截留能力为497.36 t/hm~2.地表径流量随河岸缓冲带宽度增加而减小,20m宽的河岸缓冲带就可截留40.7%,而当缓冲带宽度继续增加,截留效率并没有明显变化.

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 5m 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=0.7791P~(0.78).The biomass of bamboo litter is 2.87 t/hm~2 and max water-holding capacity is 9.13 t/hm~2 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/hm~2.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.