磨盘山4种植被类型的凋落物及其表层土壤C、N、P的化学计量特征

为滇中高原亚热带森林资源的保护与可持续利用提供依据,对玉溪磨盘山即元江栲半湿润常绿阔叶林、云南松次生混交林、天然华山松林和高山矮栎林4种植被类型的凋落物及其土壤(0~10cm)进行收集、取样测定其C、N、P含量及化学计量比,分析不同植被类型的凋落物和土壤养分之间的关系。结果表明:1)4种植被类型在凋落物的未分解层C含量,以云南松次生混交林最高,达624.04g/kg,华山松林最低,为475.76g/kg;N含量以常绿阔叶林最高,为15.49g/kg,华山松林最低,为12.2g/kg;P含量以华山松林最高,为2.3g/kg,常绿阔叶林最低,为1.91g/kg。4种植被类型凋落物半分解层N、P含量差异不显著,C含量以云南松次生混交林最高,为337.38g/kg,华山松林最低,为211.96g/kg。表层土壤C、N、P含量差异显著,均表现出云南松次生混交林最高,华山松林最低。2)4种植被类型凋落物未分解层中,C/N值以云南松混交林最小,C/P、N/P值均以高山栎林最小;半分解层中4种植被类型N/P值无显著差异,而C/N、C/P值均以常绿阔叶林为最大;表层土壤层中C/N、C/P和N/P值均无显著差异。3)高山栎林凋落物的N含量未分解层与其半分解层呈显著正相关。常绿阔叶林凋落物未分解层N含量与其半分解层中N、P含量均呈显著正相关。华山松林凋落物未分解层C含量与其表层土壤层C含量呈显著相正相关。云南松混交林未分解层N含量与其土壤层P含量呈显著正相关。

C,N and P Stoichiometry of Litter and Surface Soil of Four Forest Vegetation Types in Mopan Mountain

The C,N and P content and their stoichiometric ratio in litters and surface soils of four vegetation types (evergreen broad-leaf forest,P.yunnanensis mixed forest,P.armandii forest and Quercus aquifolioides forest) in Mopan Mountain were determined to analyze the correlations between litters and soil nutrients in four vegetation types and to provide the basis for conservation and sustainable utilization of forest resources in subtropical zone of Middle Yunnan Plateau.Results:1) The highest and lowest C content in litter un-decomposed layer is in P.yunnanensis mixed forest (624.04 g/kg) and P.armandii forest (475.76 g/kg) in four vegetation type respectively.The highest and lowest N content in litter undecomposed layer is in evergreen broad-leaf forest (15.49 g/kg) and P.armandii forest (12.2 g/kg) separately.The highest and lowest P content in litter undecomposed layer is in P.armandii forest (2.3 g/kg) and evergreen broad-leaf forest (1.91 g/kg) separately.There is no obvious difference in N and P content of half decomposition layer among four vegetation types and the highest and lowest C content in litter half undecomposed layer is in P.yunnanensis mixed forest (337.38g/kg) and Pinus armandii forest (211.96 g/kg) respectively.There is a significant difference in C,N and P content of surface soil among four vegetation types and the highest and lowest C,N and P content in surface soils of four vegetation types is in P.yunnanensis mixed forest and P.armandii forest respectively.2) The C/N in litter undecomposed layer of P.yunnanensis mixed forest is the minimum and the C/P and N/P in litter undecomposed layer of Q.aquifolioides forest is the minimum.There is no obvious difference in N/P of half decomposition layer among four vegetation types and the C/N and C/P in half decomposition layer of evergreen broad-leaf forest is the maximum among four vegetation types.There are no obvious differences in C/N,C/P and N/P in surface soil among four vegetation types.3) The litter N content of Q.aquifolioides forest is positively related to N content in litter undecompoed layer and litter half decomposition layer significantly.The N content in litter undecomposed layer of evergreen broad-leaf forest is positively related to N and P content in half decomposition significantly.The C content in litter undecomposed layer of Pinus armandii forest is positively related to C content of surface soil significantly.The N content in litter undecomposed layer of P.yunnanensis mixed forest is positively related to P content of surface soil significantly.