岷江上游中山区低效林改造对枯落物水文作用的影响

Effect of Improvement of Low-Quality and Benefit Forest on Hydrological Process of Litter in Middle-Mountain of Upper Reaches of Minjiang River

川西地区存在大面积的低效林,其生态功能极弱。通过萌蘖更新技术对岷江上游中山区低效灌丛林地进行改造,定位监测对枯落物水文作用的影响,结果显示:(1)低效林改造1年后,枯落物层厚度和贮量均有明显的改善,总贮量较改造前提高了32.68%,厚度从未分解层向半分解层或分解层转化的趋势加快;(2)改造低效林枯落物层最大持水量较改造前增加了39.60%,影响枯落物层最大持水量的主要因素是枯落物贮量和分解程度;(3)改造林地枯落物对降雨拦截能力有一定的提高;(4)岷江上游中山区枯落物持水量与浸水时间呈对数关系(S=klnt+p),枯落物的吸水速率与浸泡时间呈反曲线关系(V=p+k-t1)。今后应加强对改造林地枯落物的分解速率、土壤的生态功能等方面的研究,以系统综合地讨论这一地区低效林改造的生态效果。

There was a large of low-quality and benefit forest which had low ecological functions in western Sichuan. The hydrological process of litter was investigated through 1 year improvement on low-quality and benefit shrub forest in middle-mountain of the upper reaches of Minjiang river. The results showed： （1） the thickness and storage of litter were significantly improved and its storage increased 32.68%. Decomposition rate of litter was accelerated in improved shrubland. （2） the maximum water-holding of litter increased 39.60% than that before shrubland improved. The maximum water-holding of litter was mainly affected by the storage and the decomposition degree of litter. （3） The retaining capacity of litter on rainfall interception also increased after low-quality and benefit shrub forest were improved. （4） the relationship of the water-holding capacity and dipping water time showed logarithmic curve（ （S = klnt ＋ p） , and therelationship of the water absorption rate and time showed inverse curve （V = p ＋ kt^-1 ）. We should study the decomposition rate of litter and soil ecological function after lowquality and benefit shrub forest improved for synthetical evaluating ecological effect.