Data for: Large aquatic nitrous oxide emissions downstream of intensive horticulture driven by rain events

N2O fluxes experienced large variations (~800 fold) between dry and rain periods. Observed N2O emissions and IPCC EF5 N2O emissions were 6.27 N2O-N yr-1 and 26.5 kg N2O-N yr-1, respectively. Estimated N2O emissions ~2 km downstream of farms were 0.79% of DIN loads and 0.004% of applied fertiliser.

Aquatic N2O emissions represented ~10% of the total (CO2 + CH4 + N2O) CO2 equivalent emissions which is ~60% higher than the IPCC global N2O average. Episodic rain events rather than groundwater seepage traced by radon were the major drivers of both NOX and N2O, highlighting the importance of detailed sampling approaches to capture extreme variability in heavily fertilised catchments.