湘东丘陵区不同母质发育底土的土壤微生物商  被引量:4

Subsoil Microbial Quotient Derived from Different Parent Materials in East Hunan Province

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作  者:魏亮[1] 盛浩[1] 潘博[1] 刘广花 宋迪思[1] 

机构地区:[1]湖南农业大学资源环境学院,湖南长沙410128

出  处:《土壤与作物》2016年第4期255-260,共6页Soils and Crops

基  金:国家自然科学基金项目(41571234);国家大学生创新创业训练计划项目(G(S)CX1410)

摘  要:土壤微生物商(土壤微生物生物量碳和有机碳的比值:MBC/SOC)常作为表土有机碳和肥力变化的敏感指标,但能否应用于不同母质发育的底土仍有待验证。通过选取湘东丘陵区3种母质发育的土壤(花岗岩红壤、酸性紫色土和第四纪红土红壤),挖掘土壤剖面采集土壤样品深至母质/母岩层,研究不同母质发育底土的微生物商分布和差异。结果表明,3种母质发育土壤SOC和MBC含量随剖面加深而降低,但微生物商在某些深层底土层(淀积层、母质层)升高。在酸性紫色土和花岗岩红壤底土层,微生物较易利用的溶解性有机碳(DOC)含量也出现升高现象。底土DOC/SOC的升高可部分解释微生物商的剖面分布规律。土壤MBC含量与SOC、DOC含量均呈显著正相关关系,但MBC含量与DOC含量关系更为密切。在湘东丘陵区,微生物商无法指示不同母质发育底土的SOC和肥力差异,评价底土的肥力质量还需综合考虑SOC、MBC含量等其他土壤指标。Soil microbial quotient, ratio of soil microbial biomass C to total organic C ( MBC/SOC), is recommended as a sensitive indicator in the dynamics of topsoil organic C and soil fertility. However, whether it is applicable to subsoils derived from different par- ent materials is still unclear. Three soil profiles derived from different parent materials ( red soil derived from granite, acidic purple soil and red soil derived from Quaternary red clay) were digged down to the soil C/R horizon, and the subsoil microbial quotient and its distribution were studied. Results showed that contents of MBC and SOC decreased with soil depth, while the microbial quotient in- creased in some deep subsoil horizons ( illuvial or parent material horizon). Besides, content of soil dissolved organic carbon (DOC) was also increased in some deep horizons of acidic purple soil and red soil derived from granite. The increase of subsoil DOC/SOC can partially explain the profile distribution of microbial quotient. Regression analysis showed that the content of MBC was positively correla- ted with SOC and DOC contents, with a much higher R^2 for DOC. This study implied that microbial quotient could not indicate the dy- namics of SOC and soil fertility in subsoil derived from different parent materials in east Hunan Province, other soil indices ( e. g. , SOC and MBC) would be comprehensively considered for soil fertility evaluation.

关 键 词:有机碳 微生物生物量碳 溶解性有机碳 深层土壤 母质 

分 类 号:X144[环境科学与工程—环境科学]

 

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