Effect of urease and nitrification inhibitors on N2O emissions in Mediterranean soils

The application of nitrogen (N) fertilizers is intrinsically linked to the emissions of nitrous oxide (N₂O) and ammonia (NH₃), making their mitigation a critical global concern. One effective strategy involves the use of urease and nitrification inhibitors. Over the past three years, we have conducted multiple field and pot experiments to evaluate the impact of urea combined with urease and nitrification inhibitors on N₂O emissions and NH₃ volatilization. These studies were performed on calcareous Mediterranean soils (pH ≥ 7.3). Our findings indicate that urease inhibitors reduced NH₃-N volatilization by 25-50%. Nitrification inhibitors significantly decreased N₂O emissions. The combined application of urease and nitrification inhibitors reduced N₂O emissions by up to 67% within the first two days post-application, with emissions returning to near ambient levels within four days. In contrast, N₂O-N fluxes following urea application alone took approximately seven days to return to baseline levels. N₂O-N emissions from the double-inhibited urea were highest following irrigation or precipitation in the weeks following N applications, yet with low values (<0.03 mg-N m⁻² d⁻¹). These results highlight the effectiveness of urease and nitrification inhibitors in mitigating N₂O and NH₃ emissions, contributing to more sustainable agricultural practices.