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  • Microbial and biochemical dynamics of ectomycorrhizal mat and non-mat forest soils

    Creator:
    Kluber, Laurel A.
    Abstract:
    Dense hyphal mats formed by ectomycorrhizal (EcM) fungi are prominent features in Douglas-fir (Pseudotsuga menziesii) forest soils and have been estimated to cover up to 40% of the forest floor in some stands. Although previous studies have examined various aspects of EcM fungi, little is known about their associated microbial...
    Resource Type:
    Dissertation
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    Ectomycorrhizal Mat and Non- mat Forest Soils Abstract approved: David D. Myrold Dense hyphal mats

  • The link between nitrogen cycling and soil microbial community composition in forest soils of western Oregon

    Creator:
    Boyle, Stephanie A.
    Abstract:
    The objectives of this thesis were to examine the links between soil microbial community composition and function using the nitrogen (N) cycle as a model for these interactions and to assess the impact of environmental factors such as microclimate, vegetation type, and nutrient availability on microbial diversity and N transformations...
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    Dissertation
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    Western Oregon. Abstract approved: David D. Myrold The objectives of this thesis were to

  • Inoculation potential of soil-borne Frankia on red alder (Alnus rubra Bong.)

    Creator:
    Martin, Kendall J.
    Abstract:
    Inoculation trials were set up in fumigated nursery beds for red alder (Alnus rubra Bong.) seedling production. Frankia inoculum was applied in eight treatments: control, nodule suspension, and three levels of cell suspension (strain ArI5) applied with and without a peat carrier. Seedlings were evaluated at midseason and lifting. The...
    Resource Type:
    Dissertation
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    my life partner, Nan Pengo. I would also like to acknowledge my Major Professor, Dr. David Myrold

  • Evolution and ecology of the Ceanothus-Frankia symbiosis

    Creator:
    Jeong, Soon-Chun
    Abstract:
    The evolutionary relationship between Frankia and actinorhizal plants was evaluated by reconstructing molecular phylogenetic trees from nifH, 16S rDNA, and rbcL nucleotide sequences. Subgroupings in Frankia phylogenetic trees reconstructed from nifH and from 16S rDNA sequences were consistent in terms of plant origins of Frankia strains. Although the branching order...
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    Dissertation
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    ., and D. D. Myrold (1992). Quantitation of soil Frankia by bioassay and gene probe methods: response to

  • Response of soil microbial communities and nitrogen cycling processes to changes in vegetation inputs

    Creator:
    Brewer, Elizabeth Ann
    Abstract:
    Changes in the type and amount of plant inputs can occur gradually, as with succession, or rapidly, as with harvesting or wildfire. With global change it is anticipated that both gradual and immediate scenarios will occur at increasing frequency. Changes in vegetation inputs alter the quality and quantity of soil...
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    Dissertation
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    Input. Abstract approved: ______________________________________ David D. Myrold

  • Community composition and activities of denitrifying bacteria in soils

    Creator:
    Rich, Jeremy J.
    Abstract:
    Few studies have directly compared denitrifying community composition and activities in soils by coupling molecular-genetic techniques and traditional measures of denitnfication. I investigated communities of denitrifying bacteria from adjacent meadow and forest soils in the Cascade Mountains, Oregon. A key gene in the denitrification pathway, N₂O reductase (nosZ), served as...
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    Dissertation
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    , Rachel S. Heichen, Peter J. Bottomley, Kermit Cromack, Jr., and David D. Myrold Applied and

  • Diversity and Activity of Microbial Extracellular Peptidases in Soil

    Creator:
    Nguyen, Trang T. H.
    Abstract:
    Soil nitrogen exists largely as organic matter, including plant liter, dead animal matter, and microbial necromass. About 90% of soil organic nitrogen is proteinaceous material that is too large for plants and microorganisms to assimilate directly. Protein depolymerization therefore plays a critical role in mobilizing this organic source of nitrogen,...
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    Dissertation
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    : _____________________________________________________ David D. Myrold Soil nitrogen exists largely as organic matter, including plant liter

  • Toward understanding the nature of the soil microsite in relation to nitrogen and carbon cycling

    Creator:
    Cliff, John B.
    Abstract:
    My research has focused on understanding N and C cycling in soils at small scales. Isotope dilution methods commonly used to estimate gross rates of soil chemical transformations assume homogeneous distribution of label. I explored the effects of diffusion limitations on isotope dilution experiments in soil aggregates using spherical diffusion-reaction...
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    Dissertation
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    especially like to thank Dr. David D. Myrold and Dr. Peter J. Bottomley for their dedication, tireless

  • Using Algal Biomass as a Fertilizer

    Creator:
    Cappellazzi, Shannon B.
    Abstract:
    Algae can be used in a variety of wastewater systems to capture nutrients while fixing carbon dioxide from the atmosphere. I conducted field trials at three locations in Oregon with both corn and potato crops to assess the agronomic value and environmental impact of using the resulting algal biomass as...
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    Dissertation
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    : ______________________________________________________ David D. Myrold Algae can be used in a variety of wastewater systems to capture

  • Impact of Dairy Manure Digestate on Microbial Activities in Soil

    Creator:
    Waggoner, Ashley L
    Abstract:
    Amendments and fertilizers applied to optimize crop production and improve soil health also supply inputs of soil organic matter (SOM) and nutrients that affect soil microorganisms. In the dairy-intensive Pacific Northwest, dairy manure is stored as slurry mixtures until conditions are appropriate for soil application. During storage, the manure begins...
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    Dissertation
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    : ______________________________________________________ David D. Myrold Anne E. Taylor Amendments and fertilizers applied to optimize crop