中文摘要：

以空间代替时间的方法,对川西亚高山天然针叶林、桦木次生林、人工云杉林有机层和矿质层土壤碳、氮、磷化学计量以及土壤微生物生物量和呼吸进行比较分析.结果表明,天然针叶林转化为次生林和人工林,土壤有机层碳、氮、磷,微生物生物量碳、氮含量及微生物呼吸均显著下降,其中微生物生物量碳依次为天然林（727.98 mg/kg）〉次生林（554.56 mg/kg）〉人工林（239.83 mg/kg）,微生物生物量氮为天然林（72.56 mg/kg）〉次生林（50.42 mg/kg）〉人工林（20.78 mg/kg）,而矿质层各测定变量在3个森林群落之间差异基本不显著.各森林群落有机层土壤碳、氮、磷,微生物生物量及呼吸均显著高于矿质层,而碳氮比和微生物生物量碳氮比在土壤层次之间差异不大.相关分析表明,土壤碳、氮、磷及化学计量比及微生物变量之间存在显著相关关系.综上所述,森林转换显著影响川西亚高山土壤碳、氮、磷化学计量及微生物生物量,且影响主要体现在土壤有机层.

英文摘要：

This study aimed to explore the characteristics of soil C, N, P and microbial biomass C, N of the the three dominant subalpine forests in western Sichuan, China. The experiment used space change to stand for time change of the forest types. We investigated the soil C, N, P and microbial biomass C, N and respiration of three dominant forests （natural coniferous forest, birch secondary forest and dragon spruce plantation）. The results showed significant decreases in soil C, N, P and microbial biomass C, N and respiration in the organic layer from natural coniferous forest to secondary birch forest or spruce plantation. The order of microbial biomass carbon was natural forest （727.98 mg/kg） 〉 secondary forest （554.56 mg/kg） 〉 plantation （239.83 mg/kg）. Moreover, microbial biomass nitrogen followed the tendency of natural forest （72.56 mg/kg） 〉 secondary forest （50.42 mg/kg） 〉 plantation （20.78 mg/kg）. However, in the mineral layer no significant differences were found in any variable among the forest types. In each forest, soil C, N, P and microbial properties were higher in the organic layer than in the mineral layer. Nevertheless, there were no obvious differences in soil C/N and MBC/MBN between two soil layers. In general, there were significant correlations between soil C, N, P and microbial indicators. Taken together, forest conversion has significant effects on soil nutrients and microbial properties and its effects is mainly reflected in the organic soil layer.