Mitigation strategies for NH₃ and N₂O emissions in greenhouse agriculture: Insights into fertilizer management and nitrogen emission mechanisms

To derive localized emission coefficients and identify key influencing factors and emission mechanisms of ammonia (NH₃) and N₂O in greenhouse agriculture, we studied the emission characteristics of N₂O and NH₃, soil nitrogen changes, and soil microbial metagenomics under various fertilizer treatments. The results indicated that the N₂O and NH₃ emission coefficients for the HF and OF groups were 0.51 %, 0.26 % and 0.33 %, 0.32 %, respectively. The application of organic fertilizers significantly reduced N₂O emissions by lowering the levels of ammonium (NH₄⁺) in the soil. Organic fertilizers mitigate N₂O and NH₃ emissions by reducing the nitrification process and ammonium nitrogen in the soil. Network analysis further revealed that organic fertilizer application decreased the abundance of functional genus involved in ammonia oxidation (e.g., Nitrospira and Nitrososphaera ) while increasing the abundance of functional genes (e.g., nxrA and nxrB ) in nitrite oxidation. This shift reduces N₂O emissions during nitrification and facilitates the conversion of NH₄⁺ to NO₃⁻, which participates in the denitrification process, thereby reducing soil NH₃ emissions. Meanwhile, the organic fertilizer treatment group significantly enhanced the abundance of denitrification microorganisms, but there was no significant increase in N 2 O production. In the greenhouse agricultural ecosystem, the nitrification-derived N 2 O was predominated. • The application of organic fertilizer can significantly reduce the emission of N 2 O and NH 3 . • Organic fertilizers application diminished the abundance of ammonia oxidation functional genus. • Organic fertilizer treatment increases NH₄⁺ oxidation to NO₃⁻, reducing NH₃ emissions. • The nitrification-derived N 2 O predominates within the greenhouse agricultural ecosystem.