原始阔叶红松林下红松、蒙古栎混合凋落叶分解特征及相互作用研究

Decomposition Characteristics and Interaction of Mixed Leaf Litter Mixtures of Pinus koraiensis and Quercus mongolica in Original Broadleaved-Korean Pine Forest.

采用凋落物网袋(litter bag)分解法,模拟红松(Pinus koraiensis)(以下用P表示)和蒙古栎(Quercus mongolica)(以下用M表示)在不同演替阶段可能的组成比例(P、M/P1∶3、M/P1∶1、M/P3∶1、M)进行野外分解实验。分析不同比例的两种凋落叶混合的分解特征、相互作用及机理。结果表明:1.从质量损失率来看,与单种凋落叶分解情况相比,蒙古栎和红松凋落叶混合对凋落物分解具有促进作用,其中蒙古栎和红松(M/P)按1∶3混合分解最快,且随着蒙古栎凋落叶在混合比例中的增加,混合分解速率先减小后增大。2.从C、N元素动态看,C素在各处理的凋落叶主要表现为净释放,而N素在各处理中变现比较复杂,在各处理的红松凋落叶中表现为富集,而在各处理蒙古栎凋落叶中则表现为释放。蒙古栎凋落叶可以促进红松凋落叶C元素释放和N元素的富集,降低红松凋落叶的C/N比,促进红松凋落叶的分解。红松凋落叶能促进蒙古栎凋落物C元素释放,但对蒙古栎凋落叶N元素的释放作用不明显,对蒙古栎凋落叶的C/N比影响也并不一致。

We studied litter decomposition within mesh bag in original broadleaved-Korean pine forest by simulating possible forest litter composition proportion of Pinus koraiensis koraiensis（P） and Quercus mongolica （M） （P; M/PI：3; M/PI：I; M/P 3：1 and M） during the succession process. We clarified the decomposition characteristics, mechanism and the interaction of the mixed litter of two species （ P. koraiensis and Q. mongolica） with different composition proportion and mixing effects by using decomposition bag method. The decomposition speeds of the mixed litter of two species were faster than those of pure P. koraiensis and pure Q. mongolica leaf litter, which indicated that the mixing of P. koraiensis and Q. mongolica leaf litter accelerated the decomposition compared to the single-species leaf litter. The fastest decomposition rate was in the composition proportion of the mixed litter of M/P1 ： 3, and the rate of the mixed decomposition decreased first and then increased with the increasing of Q. mongolica in the mixed litter. For C and N dynamics, litter C showed release model in the all treatments; however, the litter N appeared complex manifestations. N was accumulated in P. koraiensis, while released in Q. mortgolica during the whole observation period. Q. mortgolica litter could accelerate C release and N enrichment in P. koraiensis litter and then reduced the C/N ratio in P. koraiensis litter. The P. koraiensis litter have a positive effect on C release of Q. mongolica, but no significant effect on N release of Q. mongolica. There was no consistent effect of P. koraiensis litter on C/N ratio of Q. mongolica litter.