Assessing and Managing Antibiotic Resistance, Nutrients, and Pathogens In Animal-Impacted Agroecosystems

Objective 1: Measure manure pathogens, antibiotic-resistant bacteria, and antibiotic resistance genes (ARB/G) in animal production systems and manure-impacted environments and mitigate their deleterious impacts. Subobjective 1A. Develop and/or validate methods to detect and quantify antibiotic resistant bacteria and genes ARB/G in beef and swine production areas, with a focus on resistance classes that are ecologically relevant to particular agricultural production systems, microbiologically relevant based on carriage of likely pathogens, and clinically relevant based on kinds of drugs used to treat infections in food animals and humans. Subobjective 1B. Measure survival of microbes and persistence of genes in manure-impacted environments. Objective 2: Improve manure land application practices to enhance crop productivity while reducing losses of reactive nitrogen and phosphorus. Subobjective 2A. Utilize rainfall simulation tests to evaluate the potential for reactive manure nitrogen (N) and phosphorus (P) to be transported in runoff from land application areas. Subobjective 2B. Utilize rainfall simulation tests to evaluate the potential for pathogens, fecal indicators, and antibiotic resistance (AR) to be transported in runoff from land application areas. Subobjective 2C. Determine if a reactive subsurface barrier can limit nitrate movement out of surface agricultural soils and into shallow aquifers. Objective 3: Assess the impact and fate of manure-associated pharmaceuticals in agroecosystems. Subobjective 3A. Evaluate how increasing concentrations of common livestock antimicrobials (monensin, lincomycin, and sulfamethazine) effect nitrification, denitrification, and decomposition in crop and pasture soils that have received beef cattle feedlot runoff or manure with crop, pasture, and stream sediments with no history of manure/runoff.