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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.
The spatial-temporal substitution method and in-situ culture method of PVC dome were used to analyze the contents of inorganic nitrogen, nitrogen mineralization rate and absorption rate in bamboo-broadleaved mixed forest and adjacent evergreen broad-leaved forest formed by the expansion of Phyllostachys pubescens in Dagangshan, Jiangxi Province The results showed that the spatial-temporal change trend of soil total inorganic nitrogen was the same in both stands. The annual average mineralization rate of bamboo-broadleaved mixed forest was lower than that of evergreen broad-leaved forest. The former was dominated by ammonification and the latter was ammoniated Which is similar to nitrification but obviously dominant during the growing season.The absorption of NH3 + -N was the main factor in the two forests, but the absorption of NO3 - N in the evergreen broad-leaved forest was obviously dominant in the growing season. The expansion of evergreen broad-leaved forest will enhance soil nitrogen ammonification, weaken the nitrification and total mineralization, and will also increase the absorption of NH4 + -N and decrease the absorption of NO3 - N and total inorganic nitrogen.