A review of ammonia emission measured using wind tunnels compared with micrometeorological techniques

Ammonia (NH3) emission from livestock manure constitutes a loss of crop‐available nitrogen (N) and poses a threat to the environment. Therefore, low NH3 emission slurry application technologies have been developed, the reduction efficiency of which has typically been estimated through measurements using wind tunnels or integrated horizontal flux (IHF) micrometeorological techniques. A recovery of 100% of released NH3 can be obtained if wind tunnels are designed to avoid pulses of wind into the tunnel through the canopy opening and leaks from the tunnels. The NH3 emission measured with wind tunnels adjusted to an air flow of 1 m/s deviated significantly (P