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Objective 1: Spatially characterize conditions within manure-impacted environments that lead to pathogen persistence, nutrient losses, and gaseous emission hot spots. Sub objective 1A: Develop, evaluate, and validate high-throughput methods for the detection, quantification and identification of microbial pathogens and fecal indicator organisms from environmental sources such as feedlot runoff, and ground and surface water samples. Sub objective 1B: Identify areas within cattle feedlot pens prone to gas emissions (odors, nutrients, and greenhouse gases) and evaluate the relationship between those areas and the spatial distribution of pathogens and fecal indicator microorganisms. Sub objective 1C: Determine the spatial distribution of contaminants, nitrogen-transforming activities, and microorganisms responsible for nitrogen transformation in a contamination plume originating from a cattle feedlot runoff holding pond. <P>
Objective 2: Develop land application practices that incorporate the use of manure as a nutrient source for crop production while minimizing potential adverse environmental impacts. Sub objective 2A: Utilize rainfall simulations tests to evaluate the potential for pathogen and nutrient runoff from manure applied to cropland. Sub objective 2B: Utilize laboratory soil columns to evaluate odor compound emissions after manure application to cropland. <P>
Objective 3: Develop manure management practices (e.g. vegetative treatment systems) to control gaseous emissions, nutrients, and microorganisms (e.g. E. coli O157:H7). Sub objective 3A: Determine the movement and persistence of nutrients, pathogens, and fecal indicator organisms within the vegetative treatment system (VTS) during standard and non-standard VTS operation. Sub objective 3B: Evaluate the antibiotic resistant phenotypes and genotypes of bacteria isolated directly from manure, and compare to bacteria from the corresponding feedlot runoff, and the agricultural fields to which the manure has been applied.
Approach:
Experiments will be conducted in the field and in the laboratory to evaluate gas emissions, nutrient transport, and microbial transport and fate associated with specific types of confined animal feeding operations and wastewater treatment processes. New high-throughput methods for the detection of specific fecal microorganisms and antibiotic resistance genes will be developed and applied towards this goal. In field studies, specific areas within manure-impacted environments (beef cattle feedlot pens, vegetative treatment areas for feedlot runoff treatment, a cattle feedlot holding pond groundwater contamination plume, and crop fields utilizing manure as fertilizer) will be identified that disproportionately emit gases (odor compounds, ammonia, and greenhouse gases) or have a large potential for nutrient or pathogen transport through the use of flux chambers and gas chromatography, by the use of artificial rainfall simulators, and by microbiological methods. In laboratory studies, molecular techniques will be used to assess microbial communities in order to understand the relationships between microbes and environmental processes affecting nutrients, emissions, and pathogen fate.