马尾松凋落物分解过程中的微量元素释放动态

Dynamic of Trace Elements Releasing in the Process of Litter Decomposition in the Pinus mussonian Plantation

为探索马尾松(Pinus massonana)凋落物在不同密度林分中微量元素的释放规律,以12 a生马尾松人工林为研究对象,采用网袋分解法,分析3种密度下马尾松凋落物分解过程中干质量损失率、4种微量元素含量和养分残留率变化。结果表明,马尾松人工林凋落物残留率在不同密度间的变化趋势均相近,密度对残留率无显著影响。不同月份残留率不同,11月至翌年1月迅速降低,然后减缓,春季和夏季加快降低,秋季又开始减缓。凋落物中4种微量元素释放模式主要为"淋溶-富集-释放"(Zn除外)。经过1 a分解,各密度林分凋落物的干质量均损失过半;平均养分残留率从大到小为Cu(84.9%)、Fe(66.3%)、Mn(55.9%)、Zn(52.6%);凋落物中Zn残留率随密度增大而减小,其他养分变化不明显。

In order to explore the releasing dynamic of trace elements in the release process of the Pinus massoniana in forest stands with different densities, the research had been carried out in three density plantation of 12-year-old P. massoniana. With a litterbag method, dynamic variation of litterfall decomposition, the content of 4 trace elements and trace elements release were analysed. The results showed that remain ratio of litterfall had a similar variation trend. ＂exponential decay type＂among different densities of plantation. No significant differences on the residual rate of density. There were different decomposition amount in different month. Seasonal variation of weight loss ratio was winterspringsummerautumn. Nutrient remain ratio of litterfall had a similar variation tendency. Release mode of Fe, Mn, Zn, Cu were mainly ＂leaching-enrichment-release＂. There were no significant differences on the density of the residual rate of different trace elements. After one year,dry weight of litterfall decomposed more than half in each density plantation. Mean of nutrient remain ratio of litterfall were respectively： Cu 84.9%, Fe 66.3%, Mn 55.9%, Zn 52.6%. Zn remain ratio of litterfall decreased with the increasing of plantation density.