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Filtering by: Creator Downing, Dave G. Remove constraint Creator: Downing, Dave G. Advisor Myrold, David D. Remove constraint Advisor: Myrold, David D. Degree Field Soil Science Remove constraint Degree Field: Soil Science

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  • 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...
    Resource Type:
    Dissertation
    Full Text:
    total N g-1 dry soil of a local stored dairy manure and digestate and a mineral N source. The manure

  • 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...
    Resource Type:
    Dissertation
    Full Text:
    et al. 1997, Naeem et al. 1994, Tilman and Downing 1994). However, despite tremendous advances in

  • 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...
    Resource Type:
    Dissertation
    Full Text:
    C ro p p H Sa n d Si lt C la y To ta l C T ot al N P* K* * S* * C a* * M g ** B

  • Ammonia-oxidizer and denitrifier populations in boreal forest soils of differing nitrogen availability

    Creator:
    Burton, Marci S.
    Abstract:
    Nitrification and denitrification are major biological processes transforming nitrogen (N) in soils to plant available N, highly leachable nitrate (NO₃⁻) and gaseous N oxides. Although many studies in the past have studied N cycling communities, the effect of increased N inputs on ammonia-oxidizer and denitrifier population dynamics is still under...
    Resource Type:
    Masters Thesis
    Full Text:
    . Dave Myrold, for giving me this opportunity in the first place, for his continuous support along the

  • An Examination of Factors Controlling the Activity of Ammonia- and Nitrite-oxidizers in Diverse Soils

    Creator:
    Giguere, Andrew T.
    Abstract:
    Nitrification is a critical step in the global nitrogen cycle involving the biological oxidation of ammonia (NH₃) to nitrite (NO₂⁻ ) and then to nitrate (NO₃⁻). The first step in nitrification is carried out by NH₃-oxidizing bacteria (AOB) and archaea (AOA), and the second by NO₂⁻-oxidizing bacteria (NOB). In addition...
    Resource Type:
    Dissertation
    Full Text:
    graduate experience. I would also like to thank my co-advisor Dave Myrold for his insights, guidance, and

  • 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...
    Resource Type:
    Dissertation
    Full Text:
    State. Eldor introduced me to Dave and Sherri introduced me to soils. Sherri has always had

  • Functional profiles of soil microbial communities in second-growth Douglas-fir forests of the Pacific Northwest

    Creator:
    McGinnis, Megan L.
    Abstract:
    Forests are one of the largest repositories of terrestrial C. Understanding factors that drive organic matter transformations and nutrient efflux from these systems is therefore highly important. Temperate forests are of particular significance due to the large fraction of C that is stored below ground in the soil. Characterizing nutrient...
    Resource Type:
    Masters Thesis
    Full Text:
    . McGinnis, Author 6 ACKNOWLEDGEMENTS First I would like to thank Dave Myrold for being my

  • Microbial community dynamics associated with rhizosphere carbon flow

    Creator:
    Butler, Jessica L.
    Abstract:
    The cycling of root-deposited photo synthate (rhizodeposition) through the soil microbial biomass is widely recognized as a critical component of ecosystem functioning. Little is currently known about the flow of photosynthate through the microbial biomass however. My research goal was to examine if and how the flow of root-deposited photo...
    Resource Type:
    Masters Thesis
    Full Text:
    : Thanks to Dr. Dave Myrold for advising me. Thank you to Drs. Dave Myrold and Peter Bottomley for writing

  • Detection of the Burkholderia cepacia complex in soil environments

    Creator:
    Miller, Suzanne C. McKenzie
    Abstract:
    Burkholderia cepacia complex (Bcc) bacteria reside in soil, plant rhizospheres, and water, but the prevalence of Bcc in outdoor environments is not clear. In this study, we sampled a variety of soil and rhizosphere environments with which people may have contact: playgrounds, athletic fields, parks, hiking trails, residential yards and...
    Resource Type:
    Masters Thesis
    Full Text:
    . cepacia complex, and whose enthusiasm, support and friendship have made this project a delight, Dr. Dave

  • Soil community dynamics in sagebrush and cheatgrass-invaded ecosystems of the northern Great Basin

    Creator:
    DeCrappeo, Nicole M.
    Abstract:
    Sagebrush steppe ecosystems in the Great Basin have become increasingly threatened by the proliferation of cheatgrass (Bromus tectorum L.), an invasive annual grass. Diverse sagebrush and perennial bunchgrass landscapes can be converted to homogenous cheatgrass grasslands mainly through the effects of fire. Although the consequences of this conversion are well...
    Resource Type:
    Dissertation
    Full Text:
    . Dave Myrold was always generous with his time and feedback. Our Tuesday morning journal club meetings