元谋干热河谷典型植被枯落物持水能力研究

Water conservation function of typical vegetation litters in Yuanmou dry-hot valley

选取元谋干热河谷3种植被恢复典型人工纯林(印楝、新银合欢、桉树),通过对林下枯落物蓄积量的实地调查和室内持水过程试验,测定枯落物的持水能力和持水过程。结果表明:1)3种林分单位面积枯落物蓄积量由大到小依次为:新银合欢(5.751t/hm2)>桉树(3.328t/hm2)>印楝(2.041t/hm2)。2)3种林分枯落物持水能力存在显著差异。最大持水量、蓄水量、最大拦蓄量和有效拦蓄量大小依次为新银合欢>桉树>印楝;自然持水量、自然持水率和最大持水率大小依次为印楝>新银合欢>桉树。3)将3种林分枯落物持水过程分析得出:枯落物持水量和吸水速率分别与浸水时间呈显著的对数关系和幂函数关系,枯落物在1h内持水量和吸水速率迅速增加,随着时间的延长,吸水速率逐渐下降,24h后基本达到饱和。

Based on the survey of litter stock and indoor water-holding test,three typical and representative pure forest plantation of vegetation restoration patterns（Azadirachta indica,Leucaena leucocephala,Eucalyptus） were selected to measure water-holding capacity and the process of water-holding of litter layer.The results showed that：①litter stock per area of three kinds of forests was in order as：Leucaena leucocephala（5.751t/hm2）Eucalyptus（3.328t/hm2）Azadirachta indica（2.041t/hm2）.②There were significant differences in litter water-holding capacity among three forests.The maximum water capacity,water storage,the largest retaining content and the effective retaining content ranked as the order of Leucaena LeucocephalAzadirachta IndicaEucalyptus;the order in the natrual water-holding capacity,natural water-holding ratio,maximum water holding ratio were Azadirachta IndicaLeucaena LeucocephalEucalyptus.③The results from the data of water-holding process were：there were an obviously logarithmic relationship and power function relationship associated with the immersion time and water-holding capacity,water absorption rate,respectively.In the first 1 hours,water-holding capacity and water absorption rate increased rapidly,but it would be slowed down and reach the saturation after 24 hours.