中文摘要：

采用时空替代法和PVC顶盖原位培养法,分析了江西大岗山毛竹扩张形成的竹-阔混交林与邻近常绿阔叶林土壤中的无机氮含量、氮矿化速率和吸收速率等指标.结果表明：两种林分土壤总无机氮含量时空变化趋势相同;竹-阔混交林年均矿化速率低于常绿阔叶林,前者以氨化作用为主,后者氨化作用与硝化作用相当,但生长季硝化作用明显占优势.两林分全年都以吸收NH4＋-N为主,但生长季常绿阔叶林对NO3--N的吸收明显占优势.说明毛竹向常绿阔叶林扩张会增强土壤氮素氨化作用、减弱硝化作用和总矿化作用,同时也会增加对NH4＋-N的吸收,减少对NO3--N和总无机氮的吸收.

英文摘要：

By the methods of space-time substitution and PVC tube closed-top in situ incubation,this paper studied the soil mineralized-N content,N mineralization rate,and N uptake rate in Phyllostachys edulis-broadleaf mixed forest（PBMF） formed by P.edulis expansion and its adjacent evergreen broadleaf forest（EBF） in Dagangshan Mountain of Jiangxi Province,China.There existed the same spatiotemporal variation trend of soil total mineralized-N（TMN） content between the two forests.The annual average N mineralization rate was slightly lower in PBMF than in EBF.In PBMF,soil N mineralization was dominated by ammonification;while in EBF,soil ammonification and nitrification were well-matched in rate,and soil nitrification was dominated in growth season（from April to October）.The N uptake by the plants in PBMF and EBF in a year was mainly in the form of NH4＋-N,but that in EBF in growth season was mainly in the form of NO3--N.These findings indicated that the expansion of P.edulis into EBF could promote the ammonification of soil N,weakened soil nitrification and total N mineralization,and also,increased the NH4＋-N uptake but decreased the NO3--N and TMN uptake by the plants.