Reducing Phosphorus Runoff and Inhibiting Ammonia Loss from Poultry Manure with Aluminum Sulfate

Abstract

Applications of aluminum sulfate (Al₂(SO₄)₃ · 14H₂O), commonly referred to as alum, to poultry litter have been shown to decrease P runoff from lands fertilized with litter and to inhibit NH₃ volatilization. The objectives of this study were to evaluate the effects of alum applications in commercial broiler houses on: (i) NH₃ volatilization (inhouse), (ii) poultry production, (iii) litter chemistry, (iv) P runoff following litter application. Two farms were used for this study: one had six poultry houses and the 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 1816 kg/house, which corresponded to 0.091 kg/bird. Each year the houses were 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 applications 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. Broilers 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 indicate that alum‐treatment of poultry litter is a very effective best management practice that reduces nonpoint source pollution while it increases agricultural productivity.