Reducing phosphorus runoff and inhibiting ammonia loss from poultry manurewith aluminum sulfate

Applications of aluminum sulfate (Al-2(SO4)(3). 14H(2)O), commonly referred to as alum, to poultry litter have been shown to decrease P runoff from la nds fertilized with litter and to inhibit NH3 volatilization. The objective s of this study were to evaluate the effects of alum applications in commer cial broiler houses on: (i) NH3 volatilization (in-house), (ii) poultry pro duction, (iii) litter chemistry, and (iv) P runoff following litter applica tion. Two farms were used for this study: one had six poultry houses and th e other had four. The litter in half of the houses at each farm was treated with alum; the other houses were controls. Alum was applied at a rate of 1 816 kg/house, which corresponded to 0.091 kg/bird. Each year the houses wer e cleaned in the spring and the litter was broadcast onto paired watersheds in tall fescue at each farm. Results from this study showed that alum appl ications lowered the litter pH, particularly during the first 3 to 4 wk of each growout. Reductions in litter pH resulted in less NH3 volatilization, which led to reductions in atmospheric NH3 in the alum-treated houses. Broi lers grown on alum-treated litter were significantly heavier than controls (1.73 kg vs. 1.66 kg). Soluble reactive phosphorus (SRP) concentrations in runoff from pastures fertilized with alum-treated litter averaged 73% lower than that from normal litter throughout a 3-yr period. These results indic ate that alum-treatment of poultry litter is a very effective best manageme nt practice that reduces nonpoint source pollution while it increases agric ultural productivity.