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dc.contributor.advisorGuertin, Phillipen_US
dc.contributor.authorValdez Zamudio, Diego
dc.creatorValdez Zamudio, Diegoen_US
dc.date.accessioned2011-12-06T13:34:30Z
dc.date.available2011-12-06T13:34:30Z
dc.date.issued2009en_US
dc.identifier.urihttp://hdl.handle.net/10150/195018
dc.description.abstractPastures established using buffelgrass (Cenchrus ciliaris L.) have shown heterogeneous responses in terms of forage production and permanence. A good alternative for determining establishment sites and predict trends in buffelgrass conditions is the use of simulation models. The objectives of this research were to determine the factors that regulate successfulness in buffelgrass pastures and to develop a model to determine suitability in areas managed for buffelgrass pastures, based on environmental, ecological, and management variables. Above ground biomass production was considered to determine suitability in sites with buffelgrass. Eight ranches with different geographic locations, environmental situations, and management conditions were sampled as preliminary study sites to measure and model plant production. The resulting model was used to estimate plant production in the 37 sampling sites of the study areas. Results of the study indicate that basal area is a good modeling parameter to estimate production in buffelgrass plants. I also found that plant production in buffelgrass is negatively affected by population density. I concluded that there exist a positive correlation between pasture management and buffelgrass plant production. Correlation analyses demonstrate that there exist significant correlations between Pasture Condition Index (PCI) and mean annual temperatures, aspect, pasture age, nitrogen and sodium content. However, after performing stepwise regressions, only three variables were significant: pasture age (PA), nitrogen content (N2), and mean annual temperature (MAT); the last two, produce a negative response on PCI.
dc.language.isoENen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectBuffelgrassen_US
dc.subjectCenchrus ciliarisen_US
dc.subjectComputer Modelingen_US
dc.subjectPasture Condition Indexen_US
dc.subjectSonoraen_US
dc.titleApplication of Computer Modeling in Buffelgrass Pastures Studiesen_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.contributor.chairGuertin, Phillipen_US
dc.identifier.oclc659752054en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.contributor.committeememberFfolliott, Peter F.en_US
dc.contributor.committeememberCastellanos Villegas, Alejandro E.en_US
dc.contributor.committeememberMarsh, Stuart E.en_US
dc.contributor.committeememberHutchinson, Charles F.en_US
dc.identifier.proquest10422en_US
thesis.degree.disciplineNatural Resourcesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-08-25T05:14:09Z
html.description.abstractPastures established using buffelgrass (Cenchrus ciliaris L.) have shown heterogeneous responses in terms of forage production and permanence. A good alternative for determining establishment sites and predict trends in buffelgrass conditions is the use of simulation models. The objectives of this research were to determine the factors that regulate successfulness in buffelgrass pastures and to develop a model to determine suitability in areas managed for buffelgrass pastures, based on environmental, ecological, and management variables. Above ground biomass production was considered to determine suitability in sites with buffelgrass. Eight ranches with different geographic locations, environmental situations, and management conditions were sampled as preliminary study sites to measure and model plant production. The resulting model was used to estimate plant production in the 37 sampling sites of the study areas. Results of the study indicate that basal area is a good modeling parameter to estimate production in buffelgrass plants. I also found that plant production in buffelgrass is negatively affected by population density. I concluded that there exist a positive correlation between pasture management and buffelgrass plant production. Correlation analyses demonstrate that there exist significant correlations between Pasture Condition Index (PCI) and mean annual temperatures, aspect, pasture age, nitrogen and sodium content. However, after performing stepwise regressions, only three variables were significant: pasture age (PA), nitrogen content (N2), and mean annual temperature (MAT); the last two, produce a negative response on PCI.


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