Ammonia Emissions from Differing Manure Storage Facilities at Two Midwestern Free-Stall Dairies

Richard H Grant,Matthew T Boehm

doi:10.3390/atmos11101108

Abstract

Dairies contribute a major portion of agricultural ammonia emissions in the United States. Emissions were monitored over two years from an anaerobic lagoon receiving manure from cows in the milking parlor and holding area in Indiana (IN), USA and a storage basin receiving manure from cows in barns as well as the milking parlor and holding area in Wisconsin (WI), USA. Emissions were monitored using open-path tunable diode lasers, sonic anemometers, and two emission models. The mean annual daily emissions at the WI storage basins (30 µg m−2 s−1) was nearly equal to that at the IN lagoon (27 µg m−2 s−1). The mean annual daily ammonia (NH3) emissions on a per animal basis were greater at the WI basins (33 g NH3 hd−1 d−1; 26 g NH3 AU−1 d−1) (hd = animal; AU = 500 kg animal mass) than at the IN lagoon (9 g NH3 hd−1 d−1; 7 g NH3 AU−1 d−1). Emissions from both storage systems were highest in the summer, lowest in the winter, and similar during the spring and fall. Emissions were strongly correlated with air temperature and weakly correlated with wind conditions. Greater emissions at the WI basins appeared to be related primarily to the characteristics of the stored manure.

Highlights

While nitrogen is critical to life, excess nitrogen (N) in the environment has a wide range of negative impacts including the degradation of air, soil, and water resources
Assuming manure deposition was uniform throughout the day, a 24 h day time-weighted cow population loading the basins consisted of the time for all lactating cows (1506 hd) to be milked and the time that cows in two barns (496 hd) were present in those barns
Area-normalized NH3 emissions were higher at the WI dairy than at the IN dairy

Summary

Introduction

While nitrogen is critical to life, excess nitrogen (N) in the environment has a wide range of negative impacts including the degradation of air, soil, and water resources. Emission inventories for the United States estimate that the agricultural production sector of the economy contributes the largest portion of the total NH3 emissions, with livestock production being the dominant source of NH3 within this sector [1]. Ammonia emissions from livestock production result from the incomplete utilization of feedstock N in livestock growth and sustenance. Between 50% and 80% of N intake is excreted in manure (urine and feces) [2,3]. Dairy and cattle production accounts for about 40% of the national NH3 emission inventory [3]. Across the United States, a wide range of production management systems are used in dairies

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Conclusion