Frequent removal of manure from laying hen houses greatly improves indoor air quality and reduces air emissions at the house level. Low ammonia (NH3) emission is critical for meeting certain regulatory limits of emissions from animal feeding operations. While manure removal, via manure belt system, is effective in improving indoor air quality and reducing house-level emissions, the challenge remains to control emissions from manure storage. Many factors affect NH3 volatilization of stored poultry manure, such as moisture content, pH, and temperature, all of which contribute to the microbial activities inside the manure stack. In this study, the effects of two manure stack surface area to volume ratio (α) (1.2 or 2.3) and two air exchange rates (β) (10 or 20 ACH) on NH3 emission of laying hen manure stacks were evaluated during a 40-d ventilated storage period. The study was carried out using environmentally controlled chambers. The results revealed that air change rates of 10 or 20 ACH had no significant effect on NH3 emission; that total NH3 emission was 2.2 g/kg manure and 3.6 g/kg manure, relatively, for α = 1.2 and 2.3 during the 40-d storage period.
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