福建和溪亚热带雨林凋落物营养元素动态

探讨了福建和溪亚热带雨林主要营养元素通过凋落物的归还动态．结果表明，该森林一年中凋落物不同组分各元素的含量具有波动性，加权平均含量为Ｎ＞Ｋ＞Ｃａ＞Ｍｇ＞Ｐ（落果Ｃａ＝Ｍｇ、落枝Ｃａ＞Ｋ）。通过凋落物归还Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ元素的年库流量，分别为８７．４１、３．８２、４０．８０、２８．８１和１５．３２ｋｇｈｍ（－２），灰分量为２８４．５７ｋｇｈｍ（－２），其中以落叶形式居最大，分别各占总量的７３．４％、６８．１％、．７７．２％、７２．９％、７４．５％和７９．９％；各元素的年库流量与年凋落物量的月分布相一致，有明显的季节性．森林地表残留物Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ元素的累积储量．分别为５４．８３、２．４５、９．６９、１７．０和９．２５ｋｇｈｍ（－２）．五种元素在林下地表的滞留时间，分别为Ｎ０．６１、Ｐ０．６１、Ｋ０．２３、Ｃａ０．５６和Ｍｇ０．５３年．

DYNAMIC OF NUTRIENT ELEMENTS IN LITTERFALL OF SUBTROPICAL RAIN FOREST OF HEXI IN FUJIAN

Study on the dynamics of nutrient elements returned to the forest floor from litterfall in a subtropical rain forest of Hexi in Fujian Province showed that the contents of elements in various fractions of litterfall fluctuated within a year, and the weighted'average contents of elements were in the order N>K>Ca>Mg>P(Ca=Mg for fruit, Ca>K for branch). The annual flows of N, P, K, Ca, Mg and ash from litterfall were 87.41, 3.82,40.80,28.81, 15.32 and 284.57kg hm-2, respectively. The pool amounts of N, P, K, Ca and Mg in residues on the floor were 54.83, 2.45, 9.69, 17.0 and 9.25kg hm-2, respectively. The residence time of the five elements on the floor was 0.61, 0.61, 0.23, 0.56 and 0.53 year, respectively.