{"683254":{"#nid":"683254","#data":{"type":"event","title":"PhD Defense by Andrew Sharkey","body":[{"value":"\u003Cp\u003ESchool of Civil and Environmental Engineering\u003Cbr\u003EPh.D. Thesis Defense Announcement\u003Cbr\u003EDeveloping Robust Agricultural Kinetic Models:\u003Cbr\u003EThe Hydroponic Cultivation of L. Sativa Lettuce in\u003Cbr\u003EControlled Environment Agriculture\u003Cbr\u003EBy Andrew Sharkey\u003Cbr\u003EAdvisor:\u003Cbr\u003EDr. Yongsheng Chen\u003Cbr\u003ECommittee Members:\u0026nbsp;\u003Cbr\u003E\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Dr. Xing Xie (CEE)\u003Cbr\u003E\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Dr. Ching-Hua Huang (CEE)\u003Cbr\u003E\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Dr. Ameet Pinto (CEE)\u003Cbr\u003E\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Dr. Rhuanito Ferrarezi (UGA Dept. of Horticulture)\u003Cbr\u003E\u003Cbr\u003EDate and Time: August 11, 2025. \u0026nbsp;1pm-3pm EST\u003Cbr\u003ELocation: Price Gilbert Memorial Library #4222 (Dissertation Defense Room)\u003Cbr\u003ETeams Meeting ID: \u0026nbsp;279 728 293 764 0\u003Cbr\u003EPassword: \u0026nbsp;Ui762w4Q\u003C\/p\u003E\u003Cp\u003E\u003Cbr\u003EABSTRACT\u003Cbr\u003EThe lifecycle of fertilizers, as the foundational components of agriculture, is\u003Cbr\u003Eriddled with inefficiencies including expensive and limited-resource supply,\u003Cbr\u003Ecentralized agricultural production, and many harmful environmental impacts.\u003Cbr\u003EFortunately, hydroponics and Controlled Environment Agriculture (CEA) offer\u003Cbr\u003Epotential solutions to issues of both centralized agricultural production and\u003Cbr\u003Eharmful environmental impacts. To resolve the remaining issues, wastewater can be recovered to provide nutrients for new generations of agricultural crops\u003Cbr\u003Edestined for human consumption.\u003Cbr\u003EHowever, in order to fully capitalize on these potential solutions, farmers\u003Cbr\u003Eand engineers require improved models which track both nutrient uptake and\u003Cbr\u003Ebiomass growth. Such fundamental models, based on Michaelis-Menten and\u003Cbr\u003EMonod reaction kinetics, have been rigorously studied for microbial populations,\u003Cbr\u003Ebut fewer studies have applied these fundamentals to agricultural populations.\u003Cbr\u003EFurthermore, agricultural populations require unique modifications before models\u003Cbr\u003Eare applicable to wastewater nutrient recovery efforts.\u003Cbr\u003EHydroponic experiments cultivated Bibb lettuce with synthetic nutrient\u003Cbr\u003Esolutions based on Modified Sonneveld\u2019s Solution, with treatments focused on\u003Cbr\u003Eindividually varying each of three limiting nutrients: nitrogen (N), phosphorus (P),\u003Cbr\u003Eand potassium (K). Researchers analyzed both plant tissue and water samples to\u003Cbr\u003Equantify changes in relative growth rates, nutrient uptake rate, and lettuce tissue\u003Cbr\u003Ecomposition as plants matured in each treatment. These results were used to\u003Cbr\u003Eincrementally address gaps to build a robust agricultural kinetic model.\u003Cbr\u003EThis model pioneers the characterization of temporally dynamic agricultural\u003Cbr\u003Egrowth rates, incorporates multiple limiting nutrients, and incrementally builds\u003Cbr\u003Eagricultural biomass to reflect the variable nutrient supply expected of reclaimed\u003Cbr\u003Edomestic wastewater. Analysis of nutrient uptake identifies ideal nutrient\u003Cbr\u003Econcentrations for hydroponic lettuce, and identifies minimum nutrient\u003Cbr\u003Econcentrations required to grow compositionally healthy and nutritious lettuce.\u003Cbr\u003EMeanwhile, the resulting models explain transitions between life stages and\u003Cbr\u003Eidentify optimal harvest days for maximizing plant biomass. While these results\u003Cbr\u003Espeak directly to lettuce grown in vertical hydroponics, the completed\u003Cbr\u003Emethodology can readily apply to other vegetables, nutrients, and environmental\u003Cbr\u003Econditions.\u003Cbr\u003EThe resulting models are finally validated against three treatments of\u003Cbr\u003Evariable nutrient supply, analyzed against alternative nutrient-based agricultural\u003Cbr\u003Emodels, and evaluated against expected domestic wastewater nutrient\u003Cbr\u003Econcentrations. This research allows and exemplifies practical application of\u003Cbr\u003Erecycling nutrients from wastewater, significantly increasing prediction accuracy,\u003Cbr\u003Ewhile relying solely on relatively non-invasive nutrient measurements from\u003Cbr\u003Ehydroponic water samples.\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003E\u003Cstrong\u003EDeveloping Robust Agricultural Kinetic Models:\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EThe Hydroponic Cultivation of \u003C\/strong\u003E\u003Cem\u003E\u003Cstrong\u003EL. Sativa Lettuce in\u003C\/strong\u003E\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EControlled Environment Agriculture\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Developing Robust Agricultural Kinetic Models: The Hydroponic Cultivation of L. Sativa Lettuce in Controlled Environment AgricultureDeveloping Robust Agricultural Kinetic Models: The Hydroponic Cultivation of L. Sativa Lettuce in Controlled Environment Ag"}],"uid":"27707","created_gmt":"2025-07-24 14:17:41","changed_gmt":"2025-07-24 14:18:26","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2025-08-11T13:00:00-04:00","event_time_end":"2025-08-11T15:00:00-04:00","event_time_end_last":"2025-08-11T15:00:00-04:00","gmt_time_start":"2025-08-11 17:00:00","gmt_time_end":"2025-08-11 19:00:00","gmt_time_end_last":"2025-08-11 19:00:00","rrule":null,"timezone":"America\/New_York"},"location":"Price Gilbert Memorial Library #4222 (Dissertation Defense Room)","extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}