川西亚高山森林凋落物不同分解阶段碳氮磷化学计量特征及种间差异

发布时间：2018-10-31 18:09

【摘要】：为了了解亚高山森林凋落物在不同分解阶段的化学计量特征,采用空间代替时间的方法,以自然状态下凋落物的3个层次——新鲜凋落物层(L)、发酵层(F)、腐殖质层(H))模拟凋落物分解的不同阶段,对川西亚高山不同林分类型(岷江冷杉天然林、粗枝云杉人工林、白桦天然林、杜鹃矮曲林)凋落物的碳氮磷(C、N、P)及可溶性碳氮磷(DOC、SN、SP)含量进行研究。结果表明:林分类型及分解阶段将显著影响凋落物分解过程中的碳氮磷含量及其化学计量比。亚高山森林凋落物可溶性有机碳、水溶性磷含量均随着分解过程的不断进行而降低,分解初期快速淋溶,而分解中后期释放变缓。4种林分比较而言,水溶性碳氮磷含量表现为:白桦杜鹃冷杉云杉,阔叶树种凋落物的可溶性碳氮磷普遍高于针叶树种,尤其在分解初期。针叶树种凋落物SN在分解过程中呈现释放模式,而阔叶树种SN呈现先富集后释放模式。凋落物C含量随着分解的不断进行而降低,冷杉、白桦及杜鹃N含量呈现先富集后释放的趋势,分解阶段对云杉与白桦各层P含量影响不显著,但冷杉却呈现先降低后升高的现象,而杜鹃则是在分解后期P含量显著降低。从总体来看,亚高山森林凋落物C/P和N/P均显著小于全球平均水平,凋落物C/N、C/P、N/P、DOC/C、SN/N、SP/P均随着分解的不断进行呈现降低的趋势。分解初期白桦和杜鹃DOC/C显著降低,而冷杉则在分解后期显著降低。冷杉N/P先升高后降低,杜鹃N/P随着分解的不断进行呈现升高趋势。这些研究结果为深入理解亚高山森林生态系统的凋落物分解进程和养分循环提供了依据。
[Abstract]:In order to understand the stoichiometric characteristics of subalpine forest litter in different decomposition stages, three layers of litter in natural state, (L), fermentation layer (F), were used to replace time in space. Humus layer (H) simulates the different stages of litter decomposition, and studies the carbon, nitrogen and phosphorus (C _ (N) of litter in different forest types (natural forest of Abies fir, plantation of Picea crassifolia, natural forest of Bai Hua, forest of rhododendron dwarf) in western mountains of Sichuan. P) and soluble carbon, nitrogen and phosphorus (DOC,SN,SP) contents were studied. The results showed that the type of stand and decomposition stage significantly affected the content of carbon, nitrogen and phosphorus and their stoichiometric ratios during litter decomposition. The content of soluble organic carbon and water soluble phosphorus in the litter of subalpine forest decreased with the process of decomposition. The water-soluble carbon, nitrogen and phosphorus contents were: the soluble carbon and nitrogen and phosphorus in litters of broad-leaved tree species were generally higher than those of coniferous species, especially in the early stage of decomposition of Bai Hua Rhododendron spruce. The release pattern of SN was observed in the decomposition process of coniferous species, while that of SN in broad-leaved species was first enriched and then released. The C content of litter decreased with the continuous decomposition. The N content of fir, Bai Hua and Rhododendron showed a tendency of enrichment and then release, but the decomposition stage had no significant effect on P content in each layer of Picea spruce and Bai Hua. However, fir decreased first and then increased, while the P content of Rhododendron decreased significantly at the later stage of decomposition. In general, C / P and N / P of subalpine forest litter were significantly lower than the global average, and the litter C / N / P / PDOC / CSN / NSPP all showed a decreasing trend with the process of decomposition. Bai Hua and Rhododendron DOC/C decreased significantly at the early stage of decomposition, while fir decreased significantly at the later stage of decomposition. The N / P of fir increased first and then decreased, and the N / P of Rhododendron increased with the continuous decomposition. These results provide a basis for further understanding the litter decomposition process and nutrient cycling in subalpine forest ecosystems.
【作者单位】：高山森林生态系统定位研究站;长江上游林业生态工程重点实验室;四川农业大学林学院;
【基金】：国家自然科学基金项目(31570605,31200345) 大学生创新训练计划项目(1510626069)~~
【分类号】：S714

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