Lime and soil moisture effects on nitrous oxide emissions from a urine patch

Liming has been mooted as a mitigation option for lowering soil N₂O emissions. This study investigated the effect of soil pH and soil water content on N₂O and N₂ emissions following the addition of synthetic urine (500 kg N ha⁻¹) containing ¹⁵N-labeled urea-N. Soil pH treatments ranged from 4.7 to 7.2 with either saturated or field capacity soil. Dinitrogen and N₂O fluxes were measured from soil cores kept on water tension tables for 85 d following urine-N addition. Soil inorganic N transformations were also monitored over time by destructively sampling soil cores on five occasions over the 85 d. At field capacity, soil pH affected the N₂O fluxes with the lowest cumulative N₂O fluxes at soil pH 5.9. Nitrous oxide losses ranged from <0.1 to 0.4% of ¹⁵N applied in the field capacity treatment but this increased to be 0.4 to 1.7% of the ¹⁵N applied in the saturated treatment. Dinitrogen fluxes were low (