Search Constraints

Start Over
Filtering by: Creator Diaz, David D. Remove constraint Creator: Diaz, David D. Advisor Myrold, David D. Remove constraint Advisor: Myrold, David D.

Search Results

  • Carbon cycling and priming of soil organic matter decomposition in a forest soil following glucose additions

    Creator:
    Diaz, David D.
    Abstract:
    Soils are a globally significant carbon (C) pool and have the potential to respond to elevated CO2 and environmental changes through positive feedback cycles that enhance the turnover of soil organic matter (SOM). Understanding the mechanisms governing the turnover of SOM is particularly important for modeling the fate of C...
    Resource Type:
    Masters Thesis
    Full Text:
    OF THE THESIS OF David D. Diaz for the degree of Master of Science in Soil Science presented on

  • 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:
    Input. Abstract approved: ______________________________________ David D. Myrold

  • Variation in communities of ammonia-oxidizing and denitrifying bacteria in Fennoscandian boreal forest soils

    Creator:
    Ghimire, Rama D.
    Abstract:
    The objective of this study was to examine the variation among ammonia-oxidizing and denitrifying communities in soils of a natural Fennoscandian boreal forest and of a forest with a long history of fertilization with different levels of nitrogen (N), and to examine whether there are any changes in the microbial...
    Resource Type:
    Masters Thesis
    Full Text:
    . Abstract approved: David D. Myrold The objective of this study was to examine the

  • Linking soluble C to microbial community composition and dynamics during decomposition of ¹³C-labeled ryegrass

    Creator:
    McMahon, Shawna K.
    Abstract:
    Ryegrass residue consists of three main C fractions: readily available soluble C, intermediately available cellulose and hemicellulose, and slowly available lignin. Changes in chemical composition during decomposition influence rate of degradation as well as composition of the microbial community involved. Use of ¹³C-labeled plant material coupled with analysis of phospholipid...
    Resource Type:
    Masters Thesis
    Full Text:
    hours for the first 5 d, and Redacted for Privacy weekly thereafter. Destructive sampling took place

  • 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:
    Dynamics Associated with Rhizoshere Carbon Flow. Abstract approved: Tbavid D. Myrold The cycling of

  • Nitrogen fixation and cycling in a mixture of young red alder and Douglas-fir

    Creator:
    Tang, James Y.
    Resource Type:
    Masters Thesis
    Full Text:
    a Mixture of Young Red Alder and Douglas-fir Abstract approved: David D. Myrold Red alder (Alnus

  • Contributions of ammonia-oxidizing bacteria and archaea to nitrification in forest soils

    Creator:
    Lu, Xinda
    Abstract:
    Prior to 2005, ammonia oxidation, the first step of nitrification, was thought mediated mainly by ammonia-oxidizing bacteria (AOB). However, the discovery of Thaumarchaeota carrying the genes coding for the ammonia monooxygenase (AMO) enzyme led to the discovery that ammonia-oxidizing archaea (AOA) also contribute to nitrification. Despite the uptick in studies...
    Resource Type:
    Masters Thesis
    Full Text:
    : _____________________________________________________________________ David D. Myrold Prior to 2005, ammonia oxidation, the first step of nitrification, was

  • 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,...
    Resource Type:
    Dissertation
    Full Text:
    : _____________________________________________________ David D. Myrold Soil nitrogen exists largely as organic matter, including plant liter

  • 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:
    : ______________________________________________________ David D. Myrold Algae can be used in a variety of wastewater systems to capture

  • 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...
    Resource Type:
    Dissertation
    Full Text:
    OF THE SOIL MICROSITE IN RELATION TO NITROGEN AND CARBON CYCLING. Abstract approved: David D