滇中常绿阔叶林及云南松林凋落物和死地被物中的养分动态

NUTRIENT DYNAMICS IN THE LITTER-FALL AND FOREST FLOOR OF EVERGREEN BROAD-LEAVED FOREST AND PINUS YUNNANENSIS FOREST IN CENTRAL YUNNAN

死地被物的数量随着凋落物数量的变化而改变,二者之间存在着动态的平衡。在营养元素的含量水平上,各类森林均表现为死地被物高于凋落物;而且在营养元素含量的排序上也有差异。其中凋落物中营养元素含量的排序在各类森林中为:常绿阔叶林中,N>Ca>Si>K>Mg>Al>P>Fe>Mn>Zn>Cu;云南松林中,Ca>N>Si>K>Al>Mg>Fe>P>Mn>Zn>Cu。而在死地被物中营养元素含量的排序依次改变为:常绿阔叶林中,Si>N>Al>Ca>Fe>K>Mg>Zn>Cu;云南松林中,Si>Al>N>Ca>Fe>K>Mg>P>Mn>Zn>Cu。森林凋落物进入地表,随着分解程度的增加(从林下 L 层转变成 F、H 层),其中灰分、Si 及 Al 有显著的增加,N、Fe、P 和 K 也有不同程度的增加,但 Ca、Mg 和 Zn 则出现下降的趋势,Mn、Cu含量的变化规律不明显。C/N 值随着凋落物分解程度的增加而下降,且随分解程度的进一步增加(从 F 层转变到 H 层),C/N 值的变化幅度逐渐变小。

The quantity of litter-fall and the standing crop of H sublayer in the forest floor of evergreen broad-leaved forest were higher than that of Pinus yunnanensis forest.The quantity of the forest floor changed with the quantity of litter-fall,and thera was a dynamic equilibrium between the litter-fall and forest floor.The conte- nt of nutrient elements of the forest floor was higher than that of litter-fall in both types.The order of nutrient element content in the forest floor differed from that in litter-fall.In the evergreen broad-leaved forest,the order was N>Ca>Si>K> Mg>Al>P>Fe>Mn>Zn>Cu,and in Pinus yunnanensis forest it was Ca>N>Si> K>Al>Mg>Fe>P>Mn>Zn>Cu.But the order of nutrient element content in the forest floor had changed:in evergreen broad-leaved forest it was Si>N> Al>Ca>Fe>K>Mg>P>Mn>Zn>Cu,the Pinus yunnanensis forest it was Si> Al>N>Ca>Fe>K>Mg>P>Mn>Zn>Cu.With increase in the intensity of litter decomposition Ash,Si and A1 had obviously increased,N,Fe,P and K had also increased in varying degrees,but there was some reduction in Ca,Zn and Mg. The ratio of carbon and nitrogen in litter decreased with increase in litter decompo- sition.