Quantifying ammonia lost to the atmosphere during manure storage on a dairy farm as influenced by management and meteorological parameters

Abstract

Storing manure provides opportunities for dairy farms to maximize using the manure value as a fertilizer, reduce handling costs, and minimize its potential to pollute the environment. However, it also presents the potential to lose the nitrogen in manure to the atmosphere through volatilization as ammonia. Knowing the quantities of nitrogen lost is critical to inform the decision-making process related to developing mitigation strategies. This study aimed to quantify ammonia lost at the farm scale level from manure stored in a clay pit at a dairy farm during two storage periods. The ammonia concentrations, manure temperature, and local meteorological factors were measured and used to calculate the ammonia flux. Further, the crusting on stored manure surface was characterized and related to ammonia loss. The ammonia flux ranged from 0.26 ± 0.01 g m−2 d−1 to 1.30 ± 0.05 g m−2 d−1, averaging 0.57 ± 0.02 g m−2 d−1. Of the local meteorological factors, the wind speed influenced ammonia loss the most, but the ammonia flux patterns were related more closely to the manure temperature than other meteorological factors. The crusting of the manure suppressed the ammonia loss. However, manure agitation before land application accounted for about 25% of the nitrogen loss. The ammonia lost during storage accounted for about 5% of the total nitrogen in the manure going into storage. The outcome of this work contributes knowledge that farmers, practitioners, and policymakers can use to design and improve the guidelines to formulate effective farm manure management and mitigation practices and regulatory programs to minimize ammonia loss from dairy farms using manure scrapers and clay storage pits as part of their manure management system.