ARS | Publication request: Impact of amendments on microbial communities associated with nitrogen mineralization in poultry litter

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 27, 2011
Publication Date: N/A

Technical Abstract: As energy costs increase poultry litter is an ever more valuable commodity. Reducing ammonia volatilization from poultry litter becomes important not only to reduce ventilation costs and improve bird performance but also to retain the nutrient value of the litter as a fertilizer. The goal of this research was to better understand the association between ammonia-producing microorganisms and nitrogen dynamics in the litter in order to improve the value of the litter and reduce risk to the flock. A combination of molecular biological (quantitative, real-time PCR, DGGE), chemical (total N, NH4-N, NO3-N) and physical (pH, moisture) measurements were used to determine microbial population and nitrogen transformations in untreated litter or litters treated with acidifiers, biological treatments, urease inhibitor or adsorber amendments. Acidification of poultry litter resulted in > 3 log increases in total fungal concentrations, with both uricolytic (uric acid degrading) and ureolytic (urea degrading) fungi increasing by > 2 logs within the first 2 to 4 weeks of the incubation. Conversely, total, uricolytic and ureolytic bacterial populations all significantly declined during this same time period. Similarly, concentrations of the enteric pathogen Campylobacter jejuni and the indicator Escherichia coli also decreased in acidified litters. Increases in uricolytic fungi were highly correlated with the mineralization of organic nitrogen in the low-pH, high N litters. Application of litter amendments consistently reduced organic N loss (0% to 15%) as compared to unamended litter (20%). Chitosan, an adsorbent, reduced organic nitrogen loss without lowering pH or increasing fungal concentrations as occurred in the acidifier amendments. The use of efficient, cost-effective litter amendments to control N mineralization, pathogen survival and/or nutrient run-off upon land application provides environmental and financial benefits that are essential for the future of sustainable poultry production.