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本文以王朗自然保护区冷杉、云杉暗针叶林为对象,在定位测定森林凋落量及其动态和枯枝落叶贮量的基础上,研究了凋落物分解速率及其主要营养元素含量的变化.结果表明:(1)地表枯枝落叶总贮量变化在30.0—91.8t/ha,其中未分解层4.9—17.8,半分解层11.5—19.7,腐殖质层13.6—57.3t/ha。(2)森林凋落的枯枝落叶量因林型不同而略有差异,平均为2.8t/ha·yr,其凋落高峰期分别在生长季开始的5月和生长季末的10月。(3)每年以凋落物形式返回林地的养分,氮为35.5kg/ha、磷为5.7kg/ha、钾为7.0kg/ha、镁为6.8kg/ha、钙为62.9kg/ha。(4)森林各种凋落物的混合物年分解率为0.3041g/g。95%的凋落物被分解需时约10年,在分解一段时间后,凋落物中的氮、钙、镁含量略有上升,钾明显减少,而磷含量变化不大。(5)森林凋落物的混合物腐解过程中,养分释放速率大小的顺序为:K>P>Mg>Ca>N,大熊猫主食竹的凋落叶则为:K>N>Ca>Mg>P。
In this paper, the changes of litter decomposition rate and its main nutrient elements were studied on the basis of the determination of forest litterfall and its dynamics and litter reserve in the fir and spruce coniferous dark brown forests of Wanglang Nature Reserve. The results showed that: (1) The total litter change of the surface litter varied from 30.0-91.8t / ha, including undegraded layer 4.9-17.8, semi-decomposed layer 11.5-19.7, and humus layer 13.6-57.3t / ha. (2) The amount of litterfall litter varies slightly with forest types, with an average of 2.8 t / ha · yr. The litterfall peak is in May and May in the beginning of the growing season and October in the end of the growing season respectively. (3) The nutrient content of forest land returned as litter was 35.5kg / ha, 5.7kg / ha of phosphorus, 7.0kg / ha of potassium, 6.8kg / ha of magnesium and 62.9kg / ha of calcium respectively. (4) The annual decomposition rate of forest litter mixture was 0.3041g / g. 95% litter decomposition takes about 10 years. After a period of decomposition, the content of nitrogen, calcium and magnesium in litter increased slightly, potassium decreased obviously, but the content of phosphorus did not change much. (5) During the decomposing process of forest litter mixture, the order of nutrient release rate was K> P> Mg> Ca> N. The litterfall of Giant Panda staple bamboo was K> N> Ca> Mg> P .