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Microbial community dynamics in long-term no-till and conventionally tilled soils of the Canadian prairies

dc.contributor.advisorWalley, Franen_US
dc.contributor.advisorGermida, Jimen_US
dc.creatorHelgason, Roberta Lynnen_US
dc.date.accessioned2010-01-15T15:31:35Zen_US
dc.date.accessioned2013-01-04T04:24:01Z
dc.date.available2011-01-15T08:00:00Zen_US
dc.date.available2013-01-04T04:24:01Z
dc.date.created2010-01en_US
dc.date.issued2010-01en_US
dc.date.submittedJanuary 2010en_US
dc.description.abstractAdoption of no-till (NT) and reduced tillage management is widespread on the Canadian prairies and together form the basic platform of soil management upon which most crop production is based. Elimination of tillage in cropping systems changes the physical and chemical characteristics of the soil profile and can affect crop growth and ultimately yield. As such, understanding how soil biota, as drivers of nutrient turnover, adapt to NT is important for maximizing crop productivity and mitigating environmental damage in agroecosystems. This work aims to achieve a greater understanding of microbial community structure and function in long-term NT versus conventionally tilled (CT) soils. Community phospholipid and DNA fingerprinting did not reveal any consistent tillage-induced shifts in microbial community structure, but demonstrated a clear influence of depth within the soil profile. While tillage did not result in broad changes in the community structure, total, bacterial and fungal biomass was consistently greater near the surface of NT soils. Further examination at one site near Swift Current, SK revealed differences in microbial biomass and community structure in NT and CT in field-formed aggregate size fractions. Measurement of mineralization and nitrification at the same site indicated that differences in the early-season turnover of N may be related to physical rather than microbial differences in NT and CT soils. Potential nitrification was higher prior to seeding than mid-season, was not affected by tillage and was correlated with ammonia oxidizer population size of archaea, but not bacteria. This work indicates that edaphic soil properties and spatial distribution of resources in the soil profile, rather than tillage management, are the primary factors driving microbial community structure in these soils.en_US
dc.identifier.urihttp://hdl.handle.net/10388/etd-01152010-153135en_US
dc.language.isoen_USen_US
dc.subjectDNA fingerprinten_US
dc.subjectlong-term experimenten_US
dc.subjectmicrobial functional groupsen_US
dc.subjectmicrobial communityen_US
dc.subjecttillageen_US
dc.subjectphospholipid fatty acid analysisen_US
dc.titleMicrobial community dynamics in long-term no-till and conventionally tilled soils of the Canadian prairiesen_US
dc.type.genreThesisen_US
dc.type.materialtexten_US
thesis.degree.departmentSoil Scienceen_US
thesis.degree.disciplineSoil Scienceen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophy (Ph.D.)en_US

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