不同宽度硬头黄竹林河岸缓冲带对地表径流的拦截效应

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

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315.6mm,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=0.7791P0.78。硬头黄竹林内枯落物生物量为2.87t/hm2,其最大持水量为9.13t/hm2,是枯落物自身干质量的3.2倍,但由于>10mm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,加快了地表径流的入渗速率,土壤的最大截留能力为497.36t/hm2。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。

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=0.7791P^0.78. 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.