毛竹和林下植被芒箕凋落物分解特征研究

目的]探讨竹林与其林下植被凋落物叶之间相互影响的潜在机制,为合理经营管理毛竹林林下植被提供理论参考。方法]采用原位分解袋法研究了四川长宁毛竹与林下植被芒箕凋落物叶分解和养分释放过程。结果](1)芒箕凋落物叶初始C、N、P含量和羟基碳高于毛竹(P 0. 05),而C∶N、C∶P、烷基碳、氧烷基碳和芳香碳低于毛竹(P 0. 05)。(2)凋落物叶分解和养分释放速率芒箕整体高于毛竹,芒箕和毛竹分解常数(k)分别为0. 58±0. 03和0. 73±0. 02,C、N、P养分释放均表现为净释放。(3)凋落物叶混合对分解速率没有显著影响,但抑制了N、P元素整个分解周期和C元素中后期的释放。(4)凋落物叶分解过程中元素含量变化格局表现为C含量和C∶N比整体呈下降趋势,N含量和N∶P比有小幅上升,P含量有微弱的下降趋势,C∶P比呈波动性变化。(5)凋落物叶分解速率与土壤温度、初始凋落物叶N和P含量呈显著正相关(P 0. 01),与初始凋落物叶的C∶N和C∶P呈极显著负相关(P 0. 01),与土壤含水量相关不显著。结论]单独分解过程中,毛竹凋落物叶分解速率低于林下植被芒箕,养分释放特征均表现为直接释放;混合分解过程中,毛竹和芒箕凋落物叶分解速率无显著混和效应,但养分释放的混合效应表现出一定负效应和不同阶段性。

Decomposition Characteristics of Litter of Phyllostachys edulis and Dicranopteris pedata

Objective] To explore the potential mechanisms of interaction and function between bamboo forest and its understory vegetation''s leaf litter, and provide a theoretical reference for the rational management of understory vegetation in Phyllostachys edulis forest.Method] The litter in situ decomposition and nutrient release process of Ph. edulis and understory vegetation (Dicranopteris pedata) in Changning of Sichuan Province were investigated using litter bag.Result] (1) The initial C, N, P contents and Carbonyl C of D. pedata were higher than those of Ph. edulis (P<0.05), while C:N, C:P and Alkyl C, O-alkyl C and Aromatic C of D. pedata were all lower than those of P. edulis (P<0.05). (2) The rate of litter decomposition and nutrient releasing of D. pedata were higher than that of Ph. edulis. The decomposition coefficient of Ph. edulis and D. pedata were 0.58±0.03 and 0.73±0.02, respectively. C, N and P nutrient release all showed net release. (3) The litter mixture of Ph. edulis and D. pedata had no significant effect on the decomposition rate, however, it significantly inhibited the release of N and P elements throughout the decomposition cycle and C elements in the late. (4) The change pattern of element content in litter decomposition process of Ph. edulis and D. pedata showed that C content and C:N ratio turned out a downward trend, and N content and N:P ratio increased slightly. P content showed a slight downward trend, and C:P ratio fluctuated. (5) Litter decomposition rate was positively correlated with soil temperature, initial litter N and P content (P<0.01), and negatively correlated with C:N and C:P of initial litter (P<0.01), but had no significant correlation with soil water content.Conclusion] There was no significant mixed effect of decomposition rate, but the mixed effect of nutrient release showed certain negative effects and different periodic features.