Aluminum sulfate and stocking density effects on poultry litter characteristics

Ammonia volatilization from poultry litter often causes high levels of atmospheric ammonia in poultry houses, which is detrimental to both farm workers and birds. Ammonia emissions from houses also aggravate environmental problems and result in a loss of fertilizer nitrogen. The aim of this study was to investigate the interaction between poultry litter treated with different levels of aluminum sulfate [Al₂(SO₄)₃?18H₂O] - (0, 200, 400 e 600 g/m²)and stocking density (12 and 14 birds/m²). Day-old chicks were used (n=532) presenting initial mean weight of 46g?2.3, in a completely randomized design in a 4x2 factorial arrangement with seven replicates per treatment. Broilers were fed ad libitum with the same diet containing ground corn and soybean meal. The litter material was rice husk. Litter samples were collected when birds were 21, 35 and 42 days old. pH and volatilized ammonia were measured at the same day, while nitrogen and dry matter samples were storage at -18?C. Statistical analyzes were performed using the proc MIXED of the SAS(R) program (version 9.2), including the fixed effect of factors (aluminum sulfate and stocking density) and interaction effect. Interaction wasn't detected for dry matter and nitrogen content (P<0.05). Interaction significant effect was observed for pH values (P<0.05), suggesting that at 35 days old, the high aluminum sulfate doses and stocking density increased these high pH values. At 42 days old, high aluminum sulfate doses and stocking density (14 birds/m²) decreased pH values. Interaction effects were observed (P<0.05) in all evaluated periods, showing decreased ammonia volatilized amount when aluminum sulfate doses were increased. Significant reductions in pH and ammonia levels were observed when litter was treated 600 g/m² of aluminum sulfate. Aluminum sulfate levels were efficient to decrease pH and ammonia volatilization to stocking density of 12 birds/m², therefore for higher densities poultry litter should be treated with quantities greater than 600 g/m².