南亚热带6种人工林土壤微生物生物量和群落结构特征

Characteristics of Soil Microbial Biomass and Community Structure under Six Different Tree Species Plantations in Southern Subtropical of China

在中国亚热带地区,随着人工造林面积的增加,导致森林结构类型单一,针叶化现象严重,土壤肥力下降等问题。本研究通过分析亚热带地区6种不同树种人工林土壤微生物生物量和群落结构的差异,探讨树种如何影响土壤微生物群落。研究发现,不同树种土壤微生物生物量与群落结构具有显著差异,木荷林土壤微生物生物量最高,福建柏林土壤真菌与细菌比值显著高于其他树种,杉木和马尾松林土壤的革兰氏阳性菌与革兰氏阴性菌比值显著高于其他树种。冗余分析表明,凋落叶碳氮比、凋落叶木质素/氮,土壤总碳、碳氮比、pH是影响微生物群落的主要环境因子。本研究结果表明,不同树种人工林主要通过调控凋落叶质量和土壤碳、氮有效性影响土壤微生物群落组成。

With the increase of reforestation plantations,problems such as the single-type forest structure,coniferization,and reduced soil fertility are more serious in southern subtropical of China.A comparative study was conducted on soil microbial biomass and community composition in six reforested tree species plantations,to understand the effects of tree species on the soil microbial biomass and community composition.The results showed that tree species had significant effects on soil total microbial biomass with the highest values were in Schima superba.Soil microbial community composition was significant different among tree species.Soil fungi:bacteria ratio under Fokienia hodginsii was significantly higher than that under other species,while Gram-positive bacteria:Gram-negative bacteria ratio under Cunninghamia lanceolata and Pinus massoniana was significantly higher than that under other species.Redundancy analysis showed that leaf litter carbon to nitrogen ratio,lignin to nitrogen ratio,soil total carbon,carbon to nitrogen ratio and pH were the main environmental factors that can explain the variation of soil microbial community among tree species.The findings indicated that the tree species can influence soil microbial composition through their effects on leaf litter quality(leaf litter carbon to nitrogen ratio and lignin:nitrogen ratio),soil carbon availability and nitrogen availability.