武夷山不同海拔土壤微生物生物量碳、氮、磷含量及其生态化学计量特征

Soil microbial biomass carbon,nitrogen,phosphorus contents and their ecological stoichiometric characteristics along an elevation gradient in the Wuyi Mountains

研究土壤微生物生物量碳(MBC)、微生物生物量氮(MBN)、微生物生物量磷(MBP)及其生态化学计量特征(MBC/MBN、MBC/MBP、MBN/MBP)沿海拔梯度变化规律,对深入理解亚热带山地土壤养分循环及其与环境变化关系具有重要意义。本研究以武夷山不同海拔(350、650、950、1050、1850和2100 m)土壤为对象,研究土壤MBC、MBN、MBP及其MBC/MBN、MBC/MBP、MBN/MBP比值对海拔变化的响应。结果表明:随海拔升高,土壤MBC、MBN总体上呈增加趋势,而MBP与MBC/MBN、MBC/MBP、MBN/MBP比值的变化并不明显。相关分析发现,土壤MBC、MBN、MBP与全碳(TC)、全氮(TN)、速效磷(AP)、可溶性有机碳(DOC)、可溶性有机氮(DON)、含水量(SWC)呈显著或极显著正相关;土壤MBC/MBN与DON、硝态氮(NO_(3)^(-)-N)、铵态氮(NH_(4)^(+)-N)呈显著正相关,与pH呈显著负相关;MBC/MBP与TN、DOC、TC、DON、SWC呈极显著或显著正相关,与C/N呈极显著负相关;MBN/MBP仅与pH呈显著正相关。冗余分析进一步显示,TC含量是影响土壤MBC、MBN、MBP及其生态化学计量比的关键因子。

The study of soil microbial biomass carbon(MBC),microbial biomass nitrogen(MBN),microbial biomass phosphorus(MBP)and their ecological stoichiometry along an elevation gradient is of great significance for understanding soil nutrient cycling and its relationship with environmental changes in subtropical mountains.In this study,soil samples were collected along an elevation gradient(350,650,950,1050,1850,and 2100 m)in the Wuyi Mountains to investigate elevational variations of the contents of MBC,MBN,MBP and the ratios of MBC/MBN,MBC/MBP,MBN/MBP.The results showed that soil MBC and MBN increased with elevation,while MBP and the ratios of MBC/MBN,MBC/MBP and MBN/MBP remained stable.MBC,MBN,and MBP were significantly positively correlated with the contents of soil total carbon(TC),total nitrogen(TN),available phosphorous(AP),dissolved organic carbon(DOC),dissolved organic nitrogen(DON),and soil water content(SWC).Soil MBC/MBN had a significantly positive correlation with soil DON,NO_(3)^(-)-N,NH_(4)^(+)-N contents and a significantly negative correlation with soil pH.Soil MBC/MBP was positively correlated with soil TN,DOC,TC,DON,SWC contents,and negatively correlated with soil C/N.Soil MBN/MBP was only positively correlated with soil pH.Results of redundancy analysis further indicated that soil TC content was the key factor influencing the contents and stoichiometry of MBC,MBN,and MBP.