Submitted to: Natural Resources Research Update (NRRU)
Publication Type: Research Technical Update
Publication Acceptance Date: 1/24/2012
Publication Date: 1/30/2012
Citation: Cook, K.L., Rothrock Jr, M.J., Lovanh, N.C., Sistani, K.R. 2012. Amending poultry litter to reduce ammonia producing bacteria. Natural Resources Research Update (NRRU). Technical update. Interpretive Summary: As fertilizer costs increase, poultry litter has become an increasingly valuable commodity. Reducing ammonia (NH3) volatilization from poultry litter is therefore important not only to reduce ventilation costs and improve bird performance but also to retain the fertilizer value of the litter. The goal of this research was to understand the association between ammonia producing microorganisms and nitrogen dynamics in poultry litter in order to improve the value of the litter and reduce risks to the flock. Ammonia is produced by mineralization of urea and uric acid. Despite the fact that it is a microbial process, little was previously known about microbial populations responsible for ammonia production in poultry litter or how they respond to litter amendments. While most litter amendments are designed to attenuate or eliminate ammonia already present within the poultry litter, the focus of this work was to identify and control the microbial communities responsible for its production.
Technical Abstract: Poultry litter is a valuable nutrient source for crop production that requires proper management to garner environmentally and financially sustainable benefits. Successful management to reduce ammonia (NH3-N) and its harmful side-effects for poultry and the environment can be aided by the use of litter amendments. The purpose of this study was to evaluate alternative litter amendments for effects on nitrogen and on microbial communities responsible for ammonia production in poultry litter. In this laboratory incubation study acidifiers, biological treatments, chemical inhibitors and adsorber amendments were added on day 0 prior to incubation. Three acidifier treatments were added: Al+Clear®, Poultry Litter Treatment®, and Poultry Guard®. Two biological treatments were included: an anti-fungal and a biological treatment containing a bacterial-enzyme-nutrient mix. A commercial urease inhibitor, and two adsorbents, wastewater treatment residual and chitosan, were added to separate treatments. Total and organic N loss, total bacteria and fungi, and microbial groups specifically associated with N transformation (i.e., organisms that produce the urease and uricase enzymes) were measured at the beginning and the end of the study. Application of litter amendments consistently reduced N loss as compared to no amendment at all. Acidification of litter reduced N loss, but also resulted in a fungal bloom (3 orders of magnitude or greater). Chitosan was the only litter amendment to perform as well as acidifiers and without the unwanted side-effect of the fungal bloom. Chitosan is readily available, cost effective, and environmentally safe. Future research should be directed toward optimization of this amendment for poultry litter treatment. The use of efficient, cost-effective litter amendments that have the potential to control not only N mineralization and loss but also pathogen survival and nutrient run-off upon application will provide environmental and financial benefits that make this research essential for the future of poultry production.