Carlton, AJCameron, KeithEdwards, GRDi, HongClough, TimothyCurrie, LDSingh, R2020-05-2120160112-9902https://hdl.handle.net/10182/11908Nitrate (NO₃⁻) leaching, associated with urine nitrogen (N) deposition during grazing is recognised as a significant environmental problem. In this study it was hypothesised that optimum irrigation could increase plant growth and uptake of urine-N deposited, thereby reducing NO₃⁻ leaching over winter. The objective of this research was therefore to determine the effect of optimum vs. deficit irrigation regimes on N uptake and dry matter yields from diverse and standard pasture species and their effects on annual NO₃⁻ leaching losses from soil. In this study ruminant urine was applied at two rates of N, 500 and 700 kg N ha⁻¹, to soil monolith lysimeters in late spring. Urine was labelled with ¹⁵N stable isotope at 5 atom% prior to application. Irrigation water was applied at optimum vs. deficit rates. Measurements of NO₃⁻ leaching, ¹⁵N abundance and pasture N uptake were undertaken for a 10 month period following urine application.4 pagesen© The Authors and FLRCnitrate (NO₃⁻)nitrate leachingruminant urine¹⁵N stable isotopepasture NirrigationConference Contribution - publishedANZSRC::079901 Agricultural Hydrology (Drainage, Flooding, Irrigation, Quality, etc.)ANZSRC::079902 Fertilisers and Agrochemicals (incl. Application)ANZSRC::0703 Crop and Pasture ProductionANZSRC::0702 Animal ProductionANZSRC::070101 Agricultural Land Management2230-3944