五大连池不同喷发时期火山土壤微生物量变化特征

Variation Characteristics of Soil Microbial Biomass in Wudalianchi during Different Volcano Eruption Periods

[目的]明确火山喷发后森林生态系统长期发展演化过程中土壤微生物量的变化特征。[方法]采用空间代替时间的方法,选择五大连池火山群中的老黑山(1721年喷发)、东焦得布山(17万年前喷发)、小孤山(28万年前喷发)、尾山(40万年前喷发)和北格拉球山(70万年前喷发)构成土壤发育的时间序列,分析土壤微生物量碳和氮含量以及土壤理化因子,探索火山喷发形成后森林生态系统长期演化过程中土壤微生物量的时间动态及其影响因子。[结果]随火山喷发形成时间增加,微生物量碳含量总体呈先增加后减少再增加的趋势;微生物量氮总体呈先增加后减少的趋势。土壤微生物量在南坡和北坡上差异显著,数量上表现为北坡>南坡。土壤微生物量碳和氮对土壤总有机碳和全氮的贡献率分别为0.92%~3.03%和1.19%~6.33%,表层(0~10 cm)高于底层(10~20 cm),贡献率的时间变化特征与土壤微生物量碳和氮的时间变化特征基本一致。土壤微生物量碳和氮呈极显著正相关;随火山喷发时间的延长,土壤微生物量与理化因子的相关程度下降。[结论]不同喷发时期火山土壤微生物量及其对土壤养分的贡献率呈波动性变化特征,不同坡向和土层深度土壤微生物量含量存在明显分异,土壤养分对微生物生存发展的限制作用随生态系统发育时间延长而降低。

[Objective]To clarify the variation characteristics of soil microbial biomass during the long-term development and evolution of forest ecosystems after volcanic eruptions.[Method]Using the method of space instead of time,Laoheishan(erupted on 1721),Dongjiaodebu(erupted at 170000 years ago),Xiaogushan(erupted at 280000 years ago),Weishan(erupted at 400000 years ago),and Beigelaqiu(erupted at 700000 years ago)in the Wudalianchi volcanic group were selected to form the time series of soil development,the carbon and nitrogen contents of soil microbial biomass and soil physicochemical factors were analyzed,and the temporal dynamics of soil microbial biomass and its influencing factors during the long-term evolution of forest ecosystems after the formation of volcanic eruptions were explored.[Result]With the increase of volcanic eruption formation time,the microbial biomass carbon content generally increased first,then decreased and finally increased;the microbial biomass nitrogen generally increased firstly and decreased then.The soil microbial biomass was significantly different between the southern and northern slopes,and the quantity was expressed as the northern slope>the southern slope.The contribution rates of soil microbial biomass carbon and nitrogen to soil total organic carbon and total nitrogen were 0.92%-3.03% and 1.19%-6.33%,respectively.The surface layer(0-10 cm)was higher than the bottom layer(10-20 cm),and the temporal variation characteristics of the contribution rate were basically consistent with the temporal variation characteristics of soil microbial biomass carbon and nitrogen.There was a extremely significant positive correlation between soil microbial biomass carbon and nitrogen.With the extension of volcanic eruption time,the correlation between soil microbial biomass and physicochemical factors decreased.[Conclusion]The soil microbial biomass and its contribution rate to soil nutrients showed fluctuating characteristics in different eruption periods volcanic.The microbial biomass content of soil in different slope directions and soil depth showed differentiation.The limiting effect of soil nutrients on microbial survival and development decreased with the extension of ecosystem development time.