Irrigation Scheduling with Soil Gas Diffusivity as a Decision Tool to Mitigate N2O Emissions from a Urine-Affected Pasture

Pastures require year-round access to water and in some locations rely on irrigation during dry periods. Currently, there is a dearth of knowledge about the potential for using mitigate N2O emissions. This study aimed losses from intensely managed pastures by adjusting frequency soil gas diffusivity (Dp/Do) thresholds. Two regimes were compared; standard treatment based farmer practice (15 mm applied every 3 days) versus an optimised where was when Dp/Do ≈0.033 (equivalent 50% plant available water). Cow urine at rate 700 kg N ha−1 simulate ruminant deposition event. In addition fluxes, moisture content monitored hourly, modelled, pasture matter production measured. Standard practices resulted higher (p = 0.09) cumulative emissions than treatment. Pasture growth rates under treatments did not differ. Denitrification re-wetting events (irrigation rain) contributed These results warrant further modelling management as mitigation option soils, thresholds, rainfall, demands evapotranspiration.