Broiler chicken (Gallus gallus domesticus) production is one of the largest agricultural sectors in the state of Georgia. Broiler litter produced by broiler facilities is rich in organic nitrogen (N), specifically urea, which can be mineralized by poultry litter urease-producing bacteria (PLUP) forming ammoniacal-N (NH3/NH4+). A large portion of NH3/NH4+ can be lost as ammonia (NH3) gas, which negatively impacts bird health and profitability. The release of NH3 from litter is strongly influenced by the pH of the litter. Flue-gas desulfurization gypsum (FGDG) has been suggested as a potential amendment to reduce NH3 volatilization from broiler litter due to the pH buffering capacity of calcium carbonate (CaCO3) precipitation. However, its effect on litter pH is not as pronounced as acidifying agents, such as aluminum sulfate (alum). The main objective of the present study was to develop an acidified-FGDG amendment that has a more pronounced effect on litter pH and NH3 volatilization than FGDG alone. We conducted a 33-d incubation in which litter pH, NH3 volatilization, PLUP-ureC gene abundance, and CaCO3 precipitation were measured. Treatments in the study included: broiler litter (control) (BL), broiler litter + 20% FGDG (BL+FGDG), broiler litter + FGDG-alum mixture (BL+FGDG+A6), broiler litter + 6% alum (BL+A6), and broiler litter + 10% alum (BL+A10). Our results indicated that ammending broiler litter with the FGDG+alum decreased litter pH (0.68 pH units) and PLUP-ureC gene abundance (> 1 log) compared to FGDG alone and the control (p < 0.05). This led to a 25% decrease in cumulative NH3 loss after 33 d. The addition of FGDG alone did not have an effect on litter pH (p = 0.36) or cumulative NH3 loss (p = 0.29) due to a lack of significant CaCO3 precipitation. Alum 6% and 10% were the most effective amendment for reducing cumulative NH3.
Chapman, Taylor; Burt, Christopher D.; Bachoon, Dave; Cabrera, Miguel L.; and Horacek, Christopher, "The Effect of an Acidified-Gypsum Mixture on Broiler Litter Urease-Producing Bacteria and Nitrogen Mineralization" (2021). Graduate Research Posters. 13.