AbstractThis study investigated the effects of irrigation frequency on N₂ and N₂O emissions from an intensively managed pasture in the subtropics. Irrigation volumes were estimated to replace evapotranspiration and were applied either once (low frequency) or split into four applications (high frequency). To test for legacy effects, a large rainfall event was simulated at the end of the experiment. Over 15 days, 7.9 ± 2.7 kg N₂ + N₂O-N ha⁻¹ was emitted on average regardless of irrigation frequency, with N₂O accounting for 25% of overall N₂ + N₂O. Repeated, small amounts of irrigation produced an equal amount of N₂ + N₂O losses as a single, large irrigation event. The increase in N₂O emissions after the large rainfall event was smaller in the high-frequency treatment, shifting the N₂O/(N₂O + N₂) ratio towards N₂, indicating a treatment legacy effect. Cumulative losses of N₂O and N₂ did not differ between treatments, but higher CO₂ emissions were observed in the high-frequency treatment. Our results suggest that the increase in microbial activity and related O₂ consumption in response to small and repeated wetting events can offset the effects of increased soil gas diffusivity on denitrification, explaining the lack of treatment effect on cumulative N₂O and N₂ emissions and the abundance of N cycling marker genes. The observed legacy effect may be linked to increased mineralisation and subsequent increased dissolved organic carbon availability, suggesting that increased irrigation frequency can reduce the environmental impact (N₂O), but not overall magnitude of N₂O and N₂ emissions from intensively managed pastures.