An experiment was conducted using 81 commercial laying hens to determine if application of an aluminum sulfate (Standard liquid [48% Al₂(SO₄)₃·14 H₂O]) based commercial product (AL⁺Clear®) to their manure would influence ammonia generation rate proportional to the concentration at which is was applied. In order to evaluate the relationship between concentration of AL⁺Clear® and ammonia generation rate the following daily manure treatments were used:

1. Water - manure sprayed daily with 40 ml of deionized-distilled water;
2. Reduced - manure sprayed daily with 40 ml of aluminum sulfate Standard liquid diluted 50%, by volume, with deionized-distilled water; and
3. Standard - manure sprayed daily with 40 ml of aluminum sulfate Standard liquid.

Regardless of AL⁺Clear® concentration all treatments were sprayed daily with 40 ml of deionized-distilled water or AL⁺Clear® aqueous solution, over approximately 1.6 ft² of manure collection area. The treatments were applied for two weeks and ammonia generation rate was measured in specialized emissions calorimeters on Day 1, 7, and 14, and manure properties were analyzed from Day 7 and 14 collections, following the start of the experiment. The results indicated that daily spraying of Reduced and Standard AL⁺Clear® treatments reduced ammonia generation rate. The percent reduction in ammonia generation (mg NH₃/h/kg manure) averaged 89 and 97% for the Reduced and Standard treatments throughout the entire experiment, respectively. There was a noticeable difference in visual appearance of the Standard treated manure when compared to the Water and Reduced treatments. The Standard treatment appeared lighter in color and was less porous on the surface. Nitrogen and phosphorus levels obtained from manure samples indicated that these factors were affected by treatments and age.

The only strong linear correlation (R² = 0.95) between the variables was between pH and soluble P₂O₅. All other linear correlations had R² values that were less than 0.40. These data indicate that the mass generation rate of ammonia production from laying hen manure may be reduced by using an aluminum sulfate topical treatment of at least 50% concentration.

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