三种相思人工林和木荷林凋落叶分解的动态分析

对3种相思（Acacia Mill．）人工林和木荷（Schima superba Gardn．et．Champ．）林凋落叶的分解速率及磷和钾的动态变化进行了研究。结果表明，在分解过程中，卷荚相思（A．cincinnata F．Muell．）林、黑木相思（A．melanoxylon R．Br．）林、马占相思（A．magium Willd．）林和木荷林凋落叶干质量残留率分别为24．37％、13．51％、12．49％和41．86％，其中马占相思林的年分解系数最大，木荷林最小。凋落叶的磷含量大多呈上升趋势，其中黑木相思林和马占相思林表现为磷的净释放；卷荚相思林则在分解过程的前180d内表现为净固持，180d后表现为净释放；木荷林基本表现为磷的净固持。凋落叶的钾含量均为单调下降，且各林分均呈现出钾的净释放，分解末期各林分的钾释放率达90．14％～98．72％。与木荷林相比，3种相思人工林对土壤养分含量，特别是磷含量的维持非常有益。

Dynamic analysis of leaf litter decomposition in three artificial forests of Acacia and Schima superba forest

The decomposition rate and dynamic change of P and K contents in leaf litter of three artificial forests of Acacia Mill. and Schima superba Gardn. et Champ. forest were studied. The results showed that the dry weight residual rate of leaf litter of A. cincinnata F. Muell. forest, A. melanoxylon R. Br. forest, A. magium Willd. forest and S. superba forest were 24.37% , 13.51% , 12.49% and 41.86% , respectively, and the annual decomposition coefficient of A. magium forest was the biggest and that of S. superba forest was the smallest. In the decomposition process of leaf litter, P content appeared an increasing tendency and K content appeared a decreasing tendency. A. rnelanoxylon and A. magium forests showed a net release of P during decomposition process, while S. superba forest generally showed a net fixation to P. A. cincinnata forest exhibited a net fixation of P in the first 180 d of decomposition, and a net release afterwards. The four forests were all presented a net release of K, and the release rate reached 90.14% -98.72% in the end of decomposition. It is concluded that compared with S. superba forest, the three artificial forests of Acacia are valuable for maintaining nutrients in soil, especially for P content.