Dana Miles1, Dennis Rowe2, and John Brooks1. (1) USDA-ARS, USDA-ARS, 810 Hwy. 12 East, Mississippi State, MS 39762-5367, (2) Experimental Statistics, Mississippi State University, Mississippi State, MS 39762-5367
Ammonia (NH3) generation from broiler litter/facilities and estimates of emission factors are central topics associated with forthcoming air quality regulations for meat-bird production. Cooling pad use in warm weather, when not operated properly, may cause wetting of the litter surface. Whereas, a minor water leak could cause subsurface wetting of the litter. Though it is known that increasing litter moisture beyond 30% can accelerate NH3 loss, management scenarios related specifically to the litter column have not been considered. A laboratory study was conducted to evaluate surface and subsurface moisture effects on litter NH3. Litter samples were weighed into cylinders with a surface area of 15.5 cm2 which were then placed inside 1000 ml containers. Supplied air (100 mL/min) and volatilized NH3 exhausted into boric acid traps. Traps were titrated each 24 hrs for 3 days. Treatments included control (no water addition), misting once or twice daily, and two levels to simulate pad infiltration (allowing 20 or 40 ml of water to move up the litter column). Two replicate studies indicated that surface misting increased NH3 generation on days 1 and 2, with a flattened response on day 3. Pad infiltration was similar to controls on days 1 and 2, but showed increased NH3 volatilization on day 3. The results indicate that mechanisms for NH3 release from litter can be affected by daily management of broiler facilities. Controlling excess moisture at the surface and base of the litter will reduce NH3 generation.