马尾松与乡土阔叶树种凋落叶混合分解过程中全碳释放的动态变化

为了调整低山丘陵区低效林林分结构，探明马尾松（Pinus massoniana Lamb.）与乡土阔叶树种凋落叶混合分解过程中的全碳（C）释放规律。本研究以华南广泛分布的马尾松、檫木（Sassafras tzumu（Hemsl.） Hemsl）、香樟（Cinnamomum camphora（Linn） Presl）以及香椿（Toona sinensis（A. Juss.） Roem.）凋落叶为研究对象，将这4个树种凋落叶按照不同树种搭配以及混合比例组合为35个处理后进行野外分解实验，探讨C释放最佳的凋落叶树种组合以及混合比例。研究发现：4个单一树种凋落叶之间，香椿凋落叶的C释放最快，檫木和香樟凋落叶次之，马尾松凋落叶最慢。31个混合凋落叶中，C释放的非加和效应随着分解时间的延长表现出先升增强后减弱的趋势，且相对于其他季节，凋落叶在秋季的非加和效应有所减弱。一针一阔树种组合中，香樟凋落叶占比≥30%的处理：PC73和PC64的协同效应较强；一针两阔和一针三阔组合中，阔叶占比≥30%且含有香椿凋落叶的处理：PST613和712、PCT631和613、PSCT7111和6121的协同效应较强。

Dynamic Changes of Total Carbon Release During Mixed Decomposition of Leaf Litter of Pinus massoniana and Native Broad-leaved Tree Species

In order to improve the structure of low-efficiency forest in hilly,the total carbon(C)release of Pinus massoniana and native broad-leaved tree species in the process of mixed decomposition of litter was investigated.The litters of Pinus massoniana,Sassafras tzumu,Cinnamomum camphora and Toona sinensis that widely distributed in South China were divided into 35 treatments according to different tree species combination and mixed proportion,and then field decomposition experiments were carried out to explore the best combination and mixing ratio of C release.The results showed that the C release of leaf litter of T.sinensis was the fastest,followed by S.tzumu and C.camphora litter,and the slowest in P.massoniana litter among the four tree species,In 31 mixed litter leaves treatments,the non-additive effect of C release increased at first and then decreased with the extension of decomposition time.Compared with other seasons,the non-additive effect of C release rate decreased in autumn.Among the combinations of P.massoniana with a broad tree,the synergistic effect of PC73 and PC64 was stronger in the treatment with broadleaf accounting for more than 30%in the combination of P.massoniana and C.camphora leaf litter;Among the combination of P.massoniana with two or three broad trees,the treatment with broad leaf accounting for more than 30%and containing T.sinensis litter:PST613 and 712,PCT631 and 613,PSCT7111 and 6121 showed stronger synergistic effect.