崇义客家梯田区森林枯落物持水特性

Water-holding Characteristics of Forest Litters in Chongyi Hakka Terrace

为了解崇义客家梯田水源区森林枯落物水文特性,进一步揭示森林的水源涵养功能,通过现场调查取样和室内实验分析等方法,对崇义客家梯田区森林枯落物的储量和持水率、持水量、吸水速率等持水特性进行了研究。结果表明:试验地各林分类型枯落物总厚度为3.0~8.6 cm,总储量为3.29~13.19 t/hm^(2),总储量整体上随总厚度的增加而增大;枯落物最大持水率为239.65%~343.54%,即枯落物最大吸持水量可达其干重的2.4~3.4倍,枯落物最大持水量为5.58~12.32 t/hm^(2),相当于0.56~1.23 mm的降雨水深;在浸泡开始2 h内,枯落物吸持水量增加较快,随着浸泡时间延长,持水量与吸水速率的变化均较为平缓,持水量与浸泡时间呈明显对数函数关系,吸水速率与浸泡时间呈明显幂函数关系。研究结果可为区域林分类型调配、森林涵养水源功能监测提供科学依据。

The aim of this research is to study the hydrologic properties of forest litters in the headwaters area of Chongyi Hakka terrace and further reveal the water conservation function of forest.The reserve,water-holding ratio,water-holding capacity and water-absorption rate of forest litters were examined based on field investigation,sampling and laboratory analysis.Results manifested that the total thickness of litters in the studied field forest ranged from 3.0 to 8.6 cm;the total reserve was between 3.29 and 13.19 t/hm^(2),which increased with the thickening of the litters;the maximum water-holding ratio ranged from 239.65%to 343.54%,implying that the largest amount of absorbed water was 2.4-3.4 times of its dry weight;the maximum water-holding capacity was 5.58-12.32 t/hm^(2),equivalent to 0.56-1.23 mm rainfall depth.The absorption amount of water surged in the first two hours of immersion;as time passed,the water-holding capacity and water-absorption rate changed gently.By nonlinear regression fitting,the relationship between water-holding capacity and immersion time could be described by logarithmic function,and the relationship between water-absorption rate and immersion time could be described by power function.The research findings offer scientific basis for regional forest types adjustment and water conservation function monitoring.