元阳梯田水源区优势树种枯落物水文特性

Hydrological Characteristics of the Dominant Tree Species in the Water Source Area of Yuanyang Terrace

对元阳梯田水源区优势树种枯落物水文特性的研究,有利于进一步揭示森林的水源涵养功能。通过野外调查采样与室内试验分析,对元阳梯田优势树种枯落物储量、持水能力、拦蓄能力以及持水过程进行了研究。结果表明:枯落物总储量为6.06~8.2t/hm^2,半分解层的枯落物储量绝大多数要大于未分解层;枯落物总厚度为6.1~8.8cm,半分解层厚度大于未分解层;枯落物半分解层自然含水率要明显高于未分解层;枯落物半分解层最大持水量要大于未分解层最大持水量,但是优势不明显,总枯落物层最大持水率为132.1%~247.3%;枯落物总的有效拦蓄量为2.07~8.01t/hm^2,其中未分解层的有效拦蓄量要大于半分解层;枯落物层持水量与吸水速率随时间变化过程中,在0~2h时间段内变化较大,浸水8h后,持水量与吸水速率两者的变化曲线均比较平缓,变化幅度较小;枯落物层持水量与浸水时间存在显著的对数关系,枯落物吸水速率与时间存在显著的幂函数关系。

The research on hydrological characteristics of dominant tree species in the water source area of Yuanyang terrace is conducive to further revealing the water conservation function of forest. Using the methods of field investigation, sampling analysis and laboratory experiments, we investigated the litter reserves, holding water ability, interception capacity and water holding process of dominant tree species of Yuanyang terrace. The results showed that the total reserves of litter was 6.06-8. 2 t/hm^2 , half-decomposed litter was more than un-decomposed litter; the total thickness of litter layer was 6.1-8.8 cm, thickness of the half-decomposed litter layer was greater than that of the un-decomposed layer; the natural water content of half-decomposed litter layer was significantly higher than that of the un-decomposed layer; the maximum water holding capacity of half-decomposed litter layer was greater than the maximum water holding capacity of un-decomposition litter, but the difference was not obvious, the maximum water holding rate of total litter ranged from 132. 1% to 247.3%; the effective interception amount of total litter was 2.07-8. 01 t/hm^2 , of which the un-decomposed effective interception amount was greater than that of the half-decomposed layer; changes of water holding capacity and water absorption rate of litter during the period of 0-2 h was large, the curves of both water holding capacity and water absorption rate were relatively flat and the change was little Mter soaking 8 h; relationship between water holding capacity of litter and water immersion time could be described by logarithmic function, and relationship between water absorption rate and time could be described by power function.