川南马尾松低效人工林不同改造模式后枯落物持水特性分析

Water Holding Characteristics of Litter Under Different Transformation Patterns of Low Efficiency Pinus massoniana Lamb.Plantation in Southern Sichuan Province

对川南马尾松低效人工林进行皆伐和林窗2种改造方式后进行枯落物持水特性研究。结果表明:林地枯落物蓄积量为对照>林窗>皆伐;其中2种改造方式后未分解层占总蓄积量的比例低于对照,已分解层蓄积量占总蓄积量的比例高于对照,半分解层蓄积量表现无规律;林地枯落物最大持水量大小为Φ30>QK>Φ10>Φ20>Φ40>CK。不同分解层次最大持水量均表现为未分解层>半分解层>已分解层,且前两层最大持水量合计超过总持水量的80%;2种改造措施有效拦蓄量(8.85~11.14t/hm^2)高于对照(7.64t/hm^2)。不同改造措施初期吸水速率林窗模式为未分解层>半分解层>已分解层,皆伐改造模式半分解层>未分解层>已分解层;对照马尾松纯林为半分解层>已分解层>未分解层,趋于饱和持水量的时间多于林窗和皆伐模式;枯落物层持水量与浸水时间存在以下关系:w=aln t+b。R^2均在0.86以上,各时段持水量与浸水时间存在较显著相关关系,证明进行马尾松低效林改造,改变了地表枯落物的组成,对提高林地水源涵养和水土保持功能起到了重要作用。

The study focused on the litter water holding characteristics of low efficiency Pinus massoniana Lamb. plantation that was transformed under 2 different ways in the south of Sichuan province. The results showed that the accumulation of litters listed in the order of control〉gap〉clear cutting. The undecomposed layer ratios for total accumulation of litters under 2 transformation patterns were lower than that of the control, while the decomposed layer ratio for total accumulation of litters was higher than that of the control. The semi-decomposed layer showed no obvious trend. Forest litter water holding quantity listed in the order of φ30〉QK〉φ10〉φ20〉φ40〉CK. The maximum water holding quantity in different levels listed in the sequence of undecomposed layer 〉 semi - decomposed layer〉 decomposed layer, and the maximum water holding quantity of the former 2 layers accounted for more than 80 % of the total water holding quantity. The effective interception amounts （from 8.85 t/hm^2 to 11.14 t/hm^2） under 2 different transformation ways were higher than that of the control （7.64 t/hm^2）. At the early period of the experiment, under the forest gap pattern, the water absorption rate of litters listed as follows： undecomposed layer〉 semi-decomposed layer〉 decomposed layer, while under the clear cutting pattern the order was semi--decomposed layer〉undecomposed layer〉decomposed layer, and under the control pattern the order was semi-decomposed layer〉decomposed layer〉undecomposed layer. The relationship between litter water holding quantity and the immersion time in water followed the equation： w=aln t＋ b. R^2 was always above 0.86. There was a significant correlation between water holding quantity and water immersion time. It indicated that the transformation on low efficiency Pinus 7nassoniana Lamb. changed the composition of litters and played an important role in improving the function of water and soil conservation.