Effect of Chemical Amendments on Ammonia Volatilization from Poultry Litter

Ammonia (NH3) volatilization from poultry litter results in a buildup of atmospheric NH3 in chicken houses, which is detrimental to both farm laborers and birds. Ammonia loss from litter is detrimental to the external environment because it results in acid rain, as well as low N/P ratios in litter, which increase the likelihood of excessive P runoff into adjacent water bodies. The objectives of this study were to determine the effect of various chemical amendments on NH3 volatilization and selected litter characteristics after 42 d. A laboratory study was conducted using the following amendments: Ca(OH)2 (calcium hydroxide), A12(SO4)~’lSH20 (alum), alum + CaCO3, FeSO4-7H20 (ferrous sulfate), and MLT (Multi-purpose Litter Treatment, commercial product). Ammonia-free air was continuously passed through air-tight chambers containing amended litter and any NH3 volatilized from the litter was trapped in boric acid solutions, which were titrated daily for NH~ content. The study was carried out for 42 d. At this time, the litter was analyzed for pH, electrical conductivity (EC), soluble, organic C (SOC), metals, and soluble and total forms of N and P. The results of this study indicated that the addition of alum to poultry litter dramatically reduces NI~ volatilization (up to 99% less volatilization than controls). Decreases in volatilization resulted in higher total and soluble N in litter, which increased NIP ratios. Several of the compounds studied (particularly alum) were effective in decreasing water-soluble P levels in litter. Therefore, we are proposing the use of alum as a litter amendment in poultry houses. W THE CURRENT SYSTEM used for poultry production, a bedding material such as wheat straw, rice hulls, or wood shavings is added to the floor of poultry houses, and five or six flocks of broilers are grown on it over a 1-yr cycle. After that time, the litter is removed and is normally land-applied as fertilizer. This re-use of litter for several flocks results in the production of NH3 gas, which can be produced in high quantities in poultry houses. For >30 yr, researchers have known that NH3 levels build up in poultry-rearing facilities, and this buildup adversely affects chickens. Scarborough (1957) and Valentine (1964) both observed NH3 levels in the 60 to 70 IxL L-~ range in the atmosphere of poultry houses. Anderson et al. (1964b) showed that NH3 levels reached 100 ~tL L-~ in the atmosphere of commercial poultry houses. In Europe, COSHH (Control of Substances Hazardous to Health) has set the limit of human exposure to NH3 at 25 ~tL L-1 for an 8-h day and 35 ~tL L-l for a 10-min exposure (Williams, 1992). Reece et al. (1979) and Anderson et al. (1964a) indicated high NH3 concentrations in poultry houses are more common i the winter, since the curtains on the houses are closed and high ventilation rates increase energy