Ammonia volatilization from different pig slurries applied on wheat stubble using different land spreading techniques under French conditions

•Injecting pig slurry is an effective way to reduce the ammonia emissions.•Injection of the slurry was heterogeneous, which influenced ammonia reduction using this technique.•Reduction in ammonia emissions after injection depends on slurry characteristics (DM, NH4+). Field experiments were conducted in Brittany (western France) in 2012 to measure and compare ammonia emissions after surface application and injection of fattening and farrowing-gestating pig slurry. Experiments were conducted on wheat stubble. Ammonia emissions were measured using wind tunnels. The results showed a reduction in ammonia emissions after injection compared to broadcast spreading whatever the slurry. However, the reduction in ammonia volatilization using the injection technique was less with the farrowing/gestating slurry (65% reduction) than with the fattening slurry (97% reduction). The lesser reduction was associated with lower emissions of total ammonia nitrogen in farrowing slurry (16% of the N-NH4+ applied) compared to the fattening slurry (74% of the N-NH4+ applied). The lower ammonia emissions were attributed to lower dry matter content and less ammonium in the farrowing/gestating pig slurry compared to the fattening pig slurry.