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dc.contributor.authorBonin, Catherine Louiseen_US
dc.date.accessioned2011-04-07en_US
dc.date.accessioned2014-03-14T20:08:41Z
dc.date.available2011-04-07en_US
dc.date.available2014-03-14T20:08:41Z
dc.date.issued2011-03-21en_US
dc.date.submitted2011-03-31en_US
dc.identifier.otheretd-03312011-095801en_US
dc.identifier.urihttp://hdl.handle.net/10919/26574
dc.description.abstractStudies suggest that diverse mixtures of plants may improve forage productivity and also be suitable as bioenergy crops. The objectives of this research were: 1) to measure the effects of native, warm-season perennial (NWSP) forage mixtures and management methods on productivity, weed biomass, nutritive value, and community composition, and 2) to identify mechanisms that generate any positive diversity-productivity relationships over a three-year establishment period. In 2008, two experiments were established to evaluate the use of native, warm-season plants in forage-livestock systems using a pool of ten native species. The first, a large-scale, three-year, experiment tested three different NWSP mixtures (switchgrass monoculture, a four-grass mixture, and a ten-species mixture) and two management methods (grazed or biomass crop). Switchgrass monocultures had the lowest forage yield and highest weed biomass in both grazed areas and biomass crop exclosures. Analysis of forage nutritive value did not show many differences among mixtures, although the monoculture tended to have higher crude protein and lower fiber concentrations than the polycultures. Management method affected community composition, with NWSP richness higher and weed species richness lower in biomass crop exclosures than in grazed areas. A second experiment examined if species richness would enhance yields through a positive biodiversity effect. It employed additive partitioning to separate the selection effect (SE) from the complementarity effect (CE) by sowing random assemblages of NWSPs at five levels of richness into small plots. Species richness was associated with increased yields in the first year only, but overyielding and positive diversity effects were present in all three years. On average, over 50% of multi-species plots overyielded and 64% exhibited a positive biodiversity effect. Both SE and CE contributed to the biodiversity effect and the importance of each effect changed over time as communities became better established. All ten species were also individually analyzed for their yield potential, nutritive value, and elemental composition. Warm-season grasses tended to be higher-yielding but of lower nutritive value. All ten NWSPs contained sufficient concentrations of eleven elements to support nonlactating cows. These experiments demonstrated that diverse NWSP mixtures may be a valuable addition to both forage and bioenergy agroecosystems.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartBonin_CL_D_2011.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectwarm-season plantsen_US
dc.subjectdiversityen_US
dc.subjectforageen_US
dc.subjectbioenergyen_US
dc.titleDiversity Relationships in Native, Warm-Season Plant Communities used for Agricultureen_US
dc.typedissertationen_US
dc.contributor.departmentCrop and Soil Environmental Sciencesen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
dc.contributor.committeechairTracy, Benjamin Franklinen_US
dc.contributor.committeememberFike, John Herschelen_US
dc.contributor.committeememberLewis, Ronald M.en_US
dc.contributor.committeememberParrish, David J.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-03312011-095801/en_US


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