Reducing nonpoint source phosphorus runoff from poultry manure with aluminum sulfate

Phosphorus (P) is generally considered to be the limiting nutrient for eutr ophication in lakes and rivers. Phosphorus runoff from soils fertilized wit h animal manures, such as poultry manure, can be relatively high even when moderate application rates are used. Recent research has indicated that tre ating poultry manure with aluminum sulfate (alum) can reduce phosphorus run off and decrease ammonia volatilization. The objectives of this study were to evaluate the effects of alum applications to poultry manure on (1) ammon ia volatilization rates from manure, (2) atmospheric ammonia levels in poul try houses, (3) poultry performance (weight gains, feed conversion, etc.), (4) energy use, and (5) P runoff from small watersheds. Two farms in NW Ark ansas, USA, were utilized for this study. Alum was applied at a rate of 181 6 kg house(-1) in half of the houses at each farm after each flock of birds and incorporated into the manure. The other houses were controls. Ammonia volatilization rates were reduced by 97% with alum applications for the fir st four weeks of each growout. Birds grown on alum-treated manure were sign ificantly heavier and had better feed conversion that birds grown in contro l houses. Energy use was also lower in alum-treated houses due to reduced v entilation requirements to remove ammonia (NH3). An economic analysis indic ated that this best management practice was very cost-effective, with a ben efit/cost ratio of 1.96. Phosphorus runoff from normal and alum-treated pou ltry manure was evaluated from field-sized plots (1 acre each) for 3 years. Phosphorus concentrations in runoff water from alum-treated manure were 75 % lower than normal manure. These results indicate that treating poultry ma nure with alum is a cost-effective best management practice that reduces no npoint source P runoff.