香港地区桃金娘灌木林的凋落物及养分回归

Litterfall and the Nutrients Return of Rhodomyrtus tomentosa Shrubland in Hong Kong.

香港桃金娘灌木林的年凋落物量在两年的测定中分别为４２９．３和５２５．２ｇ／ｍ２，枯枝和花果的凋落物年间差异十分显著。叶子和杂物则没有明显的年间差异。按１９８９年和１９９０年平均计算，桃金娘灌木林年凋落物中的氮、磷、钾量分别为２８４５、１６４和８９２ｍｇ／ｍ２。灌木林年凋落物量及养分值小于热带、亚热带常绿阔叶林，但可与马尾松林相比。气候因素对灌木林的凋落物及其养分的季节动态影响较大。养分利用效率的研究表明。

Within the two years of testing period, the total litterfall of the Rhodomyrtus tomentosa shrubland were calculated to be 429.3 and 525.2 g/m2 respectively for each year. In the litterfall, there had been significant differences between the amount of woody materials and the flowerfruit materials, but had no obvious difference between foliage materials and other materials. The average contents of N, P, K in litterfall of the shrubland in the two years were 2 845, 164 and 892 mg/m2 respectively. The quantity of and the nutrients contented in the litterfall of the shrubland were less than that of those in tropical and subtropical evergreen broadleaf forestes, but were comparable to that of those in Pinus massoniana forests. It has been found that climate change had a great effect on the seasonal dynamic changes of quantity and nutrient contents of the shrubland litterfall. The results of the study on nutrient utilization efficiency showed that Rhodomyrtus tomentosa shrubland had a higher nutrient utilization efficiency than tropical and subtropical evergreen broadleaf forests and Pinus massoniana forests had.