|Bearson, Bradley - Brad|
|HUR, MANHOI - Iowa State University|
|WURTELE, EVE - Iowa State University|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/22/2016
Publication Date: 7/1/2016
Publication URL: http://handle.nal.usda.gov/10113/6471014
Citation: Trabue, S.L., Kerr, B.J., Bearson, B.L., Hur, M., Parkin, T.B., Wurtele, E.S., Ziemer, C.J. 2016. Microbial community and chemical characteristics of swine manure during maturation. Journal of Environmental Quality. 45(4):1144-1152. doi: 10.2134/jeq2015.09.0446.
Interpretive Summary: wine odor is a leading air quality issue at the local level and modifying diets is a low input strategy at reducing odor emissions. However, how people conduct feeding trials to determine the effectiveness of alternative diets needs to be standardize. An experiment was conducted to investigate how to properly conduct a feeding trial for evaluating odor emissions. It was determine that odor emission stabilize after five week so researchers running feeding trials should conduct studies for at least five weeks for valide results. This report supply needed information on swine feeding trials showing that feeding trials should be conducted for at least five weeks for odor emissions to stabilize. Information in this report will be of value for growers, engineers, and regulatory officials on guidelines in how to conduct swine emission feeding trials.
Technical Abstract: Standardizing diet formulation studies that are designed to lower emission is needed for properly evaluating the impact diets have on emissions. Three groups of 12 pigs (84 kg initial BW) were feed a standard corn-soybean mean diet over a 13 wk period to determine how the length of manure storage affects manure composition and gas emissions. Animals were fed and manure collected and transferred to 12 manure storage containers twice daily over the 13 wk experiment. Chemical compounds monitored in both the manure and headspace gas included ammonia, hydrogen sulfide, volatile fatty acids, phenol compounds, and indole compounds. In addition, chemical properties monitored in the manure alone included pH and conductivity, while gases monitored in the headspace alone were methane and nitrous oxide. Microbial analysis of the stored manure included: 1) biomass (plate counts); 2) community structure (denaturing gradient gel electrophoresis, DGGE); and metabolic function (Biolog). All odorants in both manure and headspace gas concentrations were significantly (p < 0.01) correlated using quadratic equations peaking between wk. 5 and 13. The exceptions to these were pH and methane which did not change from initial readings. Microbial analysis showed that numbers of anaerobes and aerobes significantly (p < 0.001) declined after 1 wk. with aerobes numbers dropping even after 9 wks. Microbial community structure and metabolic utilization patterns showed that duration of manure storage had the largest impact on the microbial community. DGGE species diversity patterns declined significantly (p < 0.01) with time as substrate utilization also declined for sugars and certain amino acids, but increased in utilization of short chain fatty acids. The data suggest that feeding trials which involve manure collection should be conducted for a minimum of 5 wks for emission studies and longer if the goal is to investigate impact on greenhouse gas emissions.