金沙江河谷3种近熟人工林凋落物持水性研究

Analysis of Water-holding Capacity of Litters in Three Types of Near-mature Plantations in the Jinsha River Valleys

为了解金沙江河谷近熟人工林凋落物的涵养蓄水能力,对3种典型林分凋落物的储量、持水量、持水率和吸水速率进行了研究。结果表明:不同林型的凋落物干储量、持水量、持水率、吸水率有所差异,其大小顺序均符合:软阔林凋落物(桤木)>硬阔林凋落物(青冈)>针叶林凋落物(华山松)。凋落物持水量和持水率与浸泡时间的变化规律符合对数方程W=a×ln(t)+b(其中a和b为常数),凋落物吸水速率与时间的变化规律符合乘幂方程W=a×t^(-b),且均达到显著相关水平(P<0.05),可见软阔(桤木)林具有比另外两种林型高的保水性,通过对3种人工林凋落量及其持水性动态变化的监测和研究,凋落物自然含水量在13.75%~63.62%之间变化。未分解凋落物和半分解凋落物饱和持水率分别在85.05%~323.41%,147.66%~251.11%之间波动,半分解凋落物饱和持水率变幅相对较小。

To understand the litter water-holding capacity of near-mature plantations in the jinsha river basin,studies were made of litter reserves,water-holding capacity,water-holding rate and water absorption rate in three typical forest types of the jinsha river basin. The results showed that dry litter reserves,water holding capacity,water holding rate,water absorption rate were different in different types of forest,the order of the indexes above were all as follows： softwood forest litter（ Alnus cremastogyne） hardwood forest litter（ Cyclobalanopsis glauca） coniferous forest litter（ Pinus armandii）. the variation rule of water holding capacity,water retention rate and the immersion time conformed to the logarithmic equation W = a × ln（ T） ＋ b（ where a and B were constants）,water absorption rate and time variation rule conformed to power equation W = a × t^（-b）,and the difference reached the significant level（P 0. 05）. Softwood forest had higher water retention than the other two forest types. Through monitoring and research of dynamic variation on litter water holding capacity in three kinds of plantations,natural water content of litter varied between 13. 75% and 63. 62%,water-holding rate of undecomposed litter and half-decomposed litter varied respectively in 85. 05% ~ 323. 41% and 147. 66% ~ 251. 11%,the later varied in a smaller amplitude.