Urine patch and fertiliser N interaction: Effects of fertiliser rate and season of urine application on nitrate leaching and pasture N uptake

These results indicate that the potential for leaching of fertiliser N, applied to a urine patch, is low, and that avoiding fertiliser application over urine patches, reduces leaching losses of fertiliser-N by <2%, which is minimal in terms of total N loss mitigation. However, at high fertiliser application rates to urine patches (i.e. 400 kg N ha−1), the total N leaching from non-fertiliser (non 15N-enriched) sources can increase. Further work is required to quantify these effects at the paddock scale. The results also show that NO3− leaching losses were greater from autumn applied urine compared to spring applied urine by up to 306 kg NO3−-N ha−1.