鼎湖山南亚热带季风常绿阔叶林凋落物的养分动态

NUTRIENT DYNAMICS OF LITTERFALL IN LOWER SUBTROPICAL MONS0ON EVERGREEN BROAD-LEAVED FOREST OF DINGHUSHAN

摘要:

本文探讨鼎湖山季风常绿阔叶林调落物养分特征，分析了其动态、季节间与种间变异、构成特征等。结果表明，该群落各种群含氮量的季节变化较小，各个种的变异系数多在15％以下，但磷、钾和钠的变异较大。无论在群落还是在种的水平上，各种营养成份间均没有显著的相关性。除磷外，不同种问养分含量有显著差异，季节间则除镁外无显著差异，磷在红壤地区土壤中难于利用的主要原因可能是不同植物在磷的利用上趋同．全年通过凋落物回归土壤的养分量为氮99．88kghm^-2，磷15．03kghm^-2．钾27．01kghm^-2，钙37．11kghm^-2；镁12．19kghm^-2。在该群落中，椎栗是对落叶养分贡献最大的种，荷木其次。8月是当年凋落物养分量最高的月份，主要是由于台风作用产生大量的枝叶折落，12月则是最低月份，两者在构成上的主要区别是8月份枝条所持养分量极大，而12月份枝条极少。全年凋落物养分出现两次高峰，4月和8月，而以较寒冷的1、2、11、12月份最低。

Abstract:

This paper deals with nutrient characteristics of litterfall in forest of Dinghushansituated at 23°08'N, 112 ° 35'E. The dynamics, variation among seasons and species, and composition of litter nutrient were investigated during 1991. It was shown that 1itter nitrogen content slightly changed seasonally with variation coefficient below l5% for most species. Seasonal variation of P, K and Na contents in litterfall was greater than that of N. No significant correlation between elements was found in litterfall. The analysis of variance indicated that litter nutrient except for phosphorus differed significantly among species, and the litter nutrient except for magnesium did not differ significantly among seasons. The annual nutrient return through litterfall amounted to 37.1 1 kg hm^-2 N, 15.03 kg hm^-2 P, 27.01 kg hm^-2 K, 37.1 1 kg hm^-2 Ca, and 12.19 kg hm^-2 Mg. The amount of nutrients in litter of Castanopsis chinensis ranked first, following by Schima superb a. The nutrient peak in littelfall occurred in August when typhoon brought down lots of branches and feares. Another peak was detected in April. Lowest litter nutrient appeared in December.