Broiler farming is a significant source of gaseous emissions. The aim of this study was to assess the effects of different litter additives on the emission of NH₃, N₂O, CO₂, and CH₄ during broiler housing and subsequent manure storage. The gaseous emissions from the housing facilities were evaluated during one fattening cycle in environmentally controlled rooms with three different additives applied to the litter material (10% w/w aluminum sulphate or biochar and 2.50 mg m⁻² urease inhibitor), as well as a control. A storage experiment was conducted under laboratory conditions for 90 days to evaluate the influence of these three additives on gaseous losses. During broiler housing, the results indicated that NH₃ emissions were reduced significantly (40–60%) by litter additives, while global warming potential (GWP) emissions were reduced significantly (31%) by Alum. The addition of Biochar (a 58% reduction) had the same significant effect as Alum (a 60% reduction) to mitigate these losses. The re-application of Urease (a 41% reduction) may be required to reach an equal or higher reduction. During storage, NH₃ and GWP emissions were not significantly affected by the litter additives. During broiler housing and subsequent manure storage, NH₃ emissions were reduced significantly (22–41%) by litter additives, whereas GWP emissions did not decrease significantly. Globally, it can be concluded that Biochar appears to be a good alternative to Alum due to its equal effectiveness in mitigating NH₃ losses, without increasing the GWP potential in the housing and avoiding pollution swapping.

Background: The application of animal slurry to the soil improves its quality, as manure contains many nutrients for plants. However, this could negatively impact the environment. Objective: This field study investigated the effects of the addition of biochar after the mechanical separation of Whole pig Slurry (WS) into Solid (SF) and Liquid Fractions (LF) on Greenhouse Gases (GHG) emissions (N₂O, CO_2, and CH₄) and ryegrass (Lolium multiflorum Lam. cv magnum) yield. Methods: Biochar (1.0 kg m^-2) was applied in plots alone or together with each of the three slurries (80 kg N ha^-1) in a total of eight treatments with three replications, including just soil with and without biochar as controls. Soil properties, Greenhouse Gas (GHG) fluxes, and yield were measured during theautumn/winter growing season. Results: The results showed that the addition of biochar to these three slurries significantly increased the soil pH and showed no impact on the other physicochemical properties. The GHG emissions were not significantly different between treatments with and without biochar. The N use efficiency increased significantly in SF > WS > LF, whereas no differences were observed among these three slurries with and without biochar. Conclusion: It can be concluded that the addition of biochar combined with WS or SF/LF to sandy-loam soil appears to have no impact on GHG emissions and ryegrass yield during the autumn/winter season. Overall, this finding suggests that amounts higher than 1.0 kg m^-2 of biochar combined with SF may need to be applied to soil to reduce GHG emissions and nitrate leaching and increase N use efficiency and crop yield.