• Login
    View Item 
    •   Athenaeum Home
    • University of Georgia Theses and Dissertations
    • University of Georgia Theses and Dissertations
    • View Item
    •   Athenaeum Home
    • University of Georgia Theses and Dissertations
    • University of Georgia Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Effects of throughfall exclusion and fertilization on soil co2 efflux and its components in a loblolly pine (pinus taeda) plantation

    Thumbnail
    Date
    2016-05
    Author
    Yang, Jinyan
    Metadata
    Show full item record
    Abstract
    Soil CO2 efflux (ES) and total below-ground carbon flux (TBCF) are two critical processes that determine the balance of soil carbon in forest ecosystems. Soil CO2 efflux is composed of root CO2 efflux (ER), heterotrophic CO2 efflux (EH) and ectomycorrhizal hyphae CO2 efflux (EM). However, little is known about how ES and its components and TBCF respond to decreasing soil moisture and changes in soil fertility. The experimental design was a 2 × 2 factorial combination of fertilization and precipitation replicated in four blocks. Heterotrophic CO2 efflux, ER and EM were separated using trenched and untrenched plots. Monthly we measured ES, EH, soil temperature and soil moisture along with leaf area index (LAI) and litterfall. Fertilization reduced ES and ER while the 30% throughfall reduction had no effect on EH, ER and EM. There were correlations between ES normalized to 15oC (E15) and soil moisture in all treatments except throughfall reduction. Heterotrophic CO2 efflux normalized at 15 oC (EH15) also increased with increasing soil moisture in control and fertilization treatments. Soil temperature and moisture and their interaction explained more variation in ES and EH than in ER and EM in the four treatments. In all treatments there was a positive relationship between EH and LAI. The average annual cumulative ES in the treatments was 544 g C m-2 yr-1 (fertilization), 645 g C m-2 yr-1 (fertilization and throughfall reduction), 665 g Cm-2 yr-1 (throughfall reduction) and 695 g C m-2 yr-1 (control). The contribution of EH to ES was from 50 to 58% and the contribution of EM to ES ranged from 10% to 12% in all treatments. Fertilization also had significant effects on annual ES, litterfall, and TBCF. Compared to the control, fertilization significantly decreased TBCF by 22%. Our results indicate that fertilization plays a critical role in carbon sequestration, increasing aboveground growth and decreasing ES and TBCF. The effect of reduced soil moisture on ES and its components was less than that of fertilization, and there were interactions between soil moisture, temperature and LAI affecting these fluxes.
    URI
    http://purl.galileo.usg.edu/uga_etd/yang_jinyan_201605_phd
    http://hdl.handle.net/10724/36565
    Collections
    • University of Georgia Theses and Dissertations

    Related items

    Showing items related by title, author, creator and subject.

    • Carbon dioxide in xylem of trees 

      McGuire, Mary Anne (uga, 2009-08)
      The importance of carbon dioxide in the xylem of trees was examined. A technique was developed to continuously measure the internal CO2 concentration ([CO2]) in xylem of trees. Experiments using this technique showed a ...
    • Targeted drug delivery for brain cancer using a carborane mimic of a cholesteryl este 

      Peacock, Regina Flinn (uga, 2001-12)
      A new cholesterol-carborane conjugate (BCH) has been synthesized as a potential targeting agent for boron neutron capture therapy (BNCT) of cancers. The compound is extremely water-insoluble and was formulated in two ...
    • Stored carbon decouples soil CO2 efflux in chronically disturbed ecosystems 

      Aubrey, Douglas Patrick (uga, 2011-05)
      The tight coupling of belowground autotrophic respiration with the availability of recently assimilated carbon, and its contribution towards soil CO2 efflux, is an emerging paradigm in the ecophysiological literature. Here, ...

    About Athenaeum | Contact Us | Send Feedback
     

     

    Browse

    All of AthenaeumCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    About Athenaeum | Contact Us | Send Feedback