Chikazhe, TBeukes, PBryant, RachealKok, JLedgard, SEdwards, JPPhyn, C2024-02-022023-11-1020232463-2872https://hdl.handle.net/10182/16839The aim of this project was to model combinations (“stacks”) of cost-effective nitrogen (N) leaching mitigations within a dairy system that could reduce N leaching by 40-60%, whilst minimising losses in profitability. A FARMAX and OverseerFM combination was used to model a baseline farm representing a typical Canterbury system, and seven sequentially “stacked” mitigated systems. The mitigations were combined and stacked in the following order based on mechanism(s) of action, practicality, and cost-effectiveness: 1) reduced synthetic N fertiliser input (from 190 to 100 kg N/ha/year); 2) including Italian ryegrass in the pasture sward; 3) including plantain in the pasture sward; 4) earlier calving and drying off (by 10 days); 5) wintering on pasture and baleage; 6) standing cows off-pasture; 7) using new-generation nitrification inhibitors. The most cost-effective stack combined mitigations 1 to 5. We estimated that N leaching was reduced by 57% relative to baseline, with an 8% reduction in operating profit. Greenhouse gas emissions were reduced by 8%. The largest single reduction in N leaching was from stack #5, and it coincided with no/little change in milk production pasture eaten and had no capital cost. A careful selection of complementary mitigations could achieve significant reductions in N leaching without compromising greenhouse gas emissions and, to any great extent, profitability.pp.301-307en© The authors & the New Zealand Grassland Association.complementaritycost-effectivenessmechanismspracticalityStacking nitrogen leaching mitigations in a Canterbury dairy system whilst minimising profitability lossesJournal Article10.33584/jnzg.2023.85.36382463-2880ANZSRC::300404 Crop and pasture biochemistry and physiologyANZSRC::300406 Crop and pasture improvement (incl. selection and breeding)ANZSRC::300407 Crop and pasture nutritionANZSRC::300411 Fertilisers (incl. application)ANZSRC::300302 Animal managementANZSRC::300301 Animal growth and developmenthttps://creativecommons.org/licenses/by-nc-nd/4.0/Attribution-NonCommercial-NoDerivatives