鼎湖山某些植物群落根系生物量及其氮素动态

 本文用挖土柱及埋土柱法测定了鼎湖山生物圈保护区季风常绿阔叶林，黄果厚壳桂、鼎湖钓樟群落的根系生物量和年生长量。用自动离子分析仪分析了根的含氮量并研究了根系的氮素动态。结果表明，根系生物量(t／ha)为35.43，其中活根26.63，死根8.8；根的生长量(kg／ha·a)是3.74。根库贮氮量(kg／ha)为279.23，其中活根库为202.25，死根库为76.98；每年新生根系积累的氮素为57.55kg／ha。每年新生根系生产量及其氮素积累量占整个根库生物量及其氮素贮量的百分率分别为10.6及20.6，根库年生长量及其氮素积累的比率均较高，群落正处在生长发育盛期。

ROOT BIOMASS AND ITS NITROGEN DYNAMIC OF SOME COMMUNITIES IN DINGHUSHAN

The root biomass and the annual root growth of Cryptocarya concinna, Lindera chunk community in Dinghushan Biosphere reserve were investigated by the method of soil columu. The nitrogen concentration of roots was determined by the automaticion analyzer(Quikchem R), and the nitrogen accumulation and dynamics of root pool were also estimated. The results shown that the root biomass(t/h)was 35.43 including live root of 26.63 and dead root 8.8;the annual root growth was 3.74t/h·a; the nitrogen storage in root pool was 279.23 kg/h (202.25 in live pool and 76.98 in dead pool); the annual root growth absorbed and accumulated 57.55 kg/h·a of nitrogen.The ratio of annual root growth and its nitrogen accumulation in total biomass and nitrogen storage of root pool appeared to be higher, they were 10.6 and 20.6 respectively. Therefore, it was considered that the Cryptocarya concinna, Lindera chunii community is in a vigorous stage of growth and development.