中文摘要：

采用室内培养法对川西亚高山3个典型森林群落（天然林、云杉人工林和桦木次生林）有机层和矿质层土壤铵态氮（NH_4＋-N）、硝态氮（NO_3--N）积累量及净氮矿化速率进行测定.结果表明：培养4周后,天然林、云杉人工林和桦木次生林土壤有机层铵态氮含量分别增加356.85%、258.33%和176.81%,硝态氮含量分别增加872.92%、326.25%和120.32%,净氨化速率、净硝化速率和净氮矿化速率总体表现为天然林〉桦木次生林〉云杉人工林.方差分析表明,森林类型和土壤层次及其交互作用对土壤无机氮积累量和矿化速率均有显著影响.土壤净氮矿化速率和土壤初始化学性质之间存在显著相关关系.综上所述,森林转化显著影响川西亚高山森林土壤氮矿化潜力,主要体现在土壤有机层;川西亚高山土壤净氮矿化速率在很大程度上受控于底物数量和质量.

英文摘要：

Both deforestation and reforestation causes great impact on soil nitrogen cycling through transformation of the forest community. This research aimed to explore the characteristics of the nitrogen mineralization in soil of the subalpine forest in western Sichuan, China. Soil samples from three adjacent forest ecosystems （natural coniferous forest, dragon spruce plantation and birch secondary forest） were incubated in the laboratory to examine the effects of transformation of the forest community on rates of nitrogen mineralization, nitrification and ammonification. The results showed that soil nitrogen mineralization changed with the transformation of the forest community. The variations in the transformation were mainly reflected in the soil organic layer. In the organic layer, ammonium N increased by 3.56, 0.58, 1.77 folds, nitrate N increased by 8.73, 3.27, 1.21 folds, respectively. The rates of nitrogen mineralization, nitrification and ammonification increased in the order of natural coniferous forest 〉 dragon spruce plantation 〉 birch secondary forest. Such results indicated that the forest transformation significantly impacts the soil nitrogen mineralization potential; additionally, soil nitrogen mineralization is controlled by quality and quantity of soil substrates in this specific area.