Australian N2O Research Program Highlights Top Findings

1. n2o.net.au N2O Network The Australian Nitrous Oxide Research Program (NORP) Peter Grace

2. Acknowledgements • Graeme Schwenke (NSW I&I) • Louie Barton (UWA) • Clemens Scheer (QUT) • Sally Officer & Kevin Kelly (Vic DPI) • Weijin Wang (Qld DERM) • Deli Chen & Helen Suter (Uni Melb.)

3. Why N2O? • Global warming potential is 300 x CO2 • Principally emitted from N sources applied to soils • Intimately linked to crop and pasture production and resource use efficiency (profitability) • Mitigation is a permanent, avoided emission

4. Fertiliser etc Why N2O? N2O N2O NH4+ NO3+ N2 Nitrification Denitrification

5. Why N2O? N2O N2O NH4+ NO3+ N2 Nitrification Denitrification < Field capacity Saturated Soil water content

6. Why N2O? LABILE N2O N2O CARBON NH4+ NO3+ N2 Nitrification Denitrification < Field capacity Saturated Soil water content

7. Why N2O? N2/N2O = 30+ N2O N2O NH4+ NO3+ N2 Nitrification Denitrification < Field capacity Saturated Soil water content

8. NORP Objectives • Reduced uncertainty re the magnitude of N2O, CH4 and CO2 emissions in response to management. • Evidence based mitigation practices and systems. • Improve the accuracy of simulation models and the national greenhouse gas inventory. • Provide technical support for NAMI (National Adaptation and Mitigation Initiative)

9. NORP Core Field Sites Mackay Kingsthorpe Wongan Hills Tamworth` Hamilton Terang

15. NORP Core Field Sites Mackay Rainfed grains Kingsthorpe Wongan Hills Tamworth` Rainfed grains Hamilton Rainfed grains Terang

16. Wongan Hills, Western Australia Louise Barton, UWA Rainfed, lupin-wheat & wheat-wheat rotation •Reducing N2O emissions by raising soil pH (via liming). •Reducing CO2 emissions from urea by substituting urea with grain-legume fixed N.

17. Tamworth, New South Wales Graeme Schwenke, I&I NSW Rainfed grains •Reducing N2O emissions through inclusion of grain. legumes to reduce N fertilizer inputs within a rotation.

18. Hamilton, Victoria Sally Officer, DPI Vic Rainfed, legume/wheat rotation after pasture •N2O and CO2 emissions from direct drilled and conventionally sown legume/wheat rotations, with and without the use of nitrification inhibitors. Late August Early October Late November

19. NORP Core Field Sites Rainfed grains/sugar cane Mackay Irrigated grains/cotton Rainfed grains Kingsthorpe Wongan Hills Tamworth` Rainfed grains Hamilton Rainfed grains Terang

20. Kingsthorpe, Queensland Peter Grace, Queensland University of Technology Irrigated cotton-grains •Reducing N2O emissions through irrigation and nitrogen management.

21. NORP Core Field Sites Rainfed grains/sugar cane Mackay Irrigated grains/cotton Rainfed grains Kingsthorpe Wongan Hills Tamworth` Rainfed grains Hamilton Rainfed grains Dairy Terang

22. Terang, Victoria Kevin Kelly, DPI Victoria Pasture systems •Impact of inhibitors on N2O emissions following the application of urine to high rainfall dairy pastures.

23. NORP Core Field Sites Rainfed grains/sugar cane Mackay Rainfed grains Kingsthorpe Wongan Hills Tamworth` Rainfed grains Hamilton Rainfed grains Terang

24. Mackay, Queensland Dr Weijin Wang, Sugar Research & Development Corporation Rainfed, sugar cane • Reducing N fertilizer inputs through use of legume-fixed N. •Impact of nitrification inhibitors on N2O emissions.

25. NORP Core Field Sites + Mackay Kingsthorpe Wongan Hills Wollongbar Narrabri Tamworth` Hamilton Griffith Terang

26. Daily N2O flux (+/- inhibitor) - dairy Terang (Vic) 240 0.60 200 0.50 Soil water (mm3/mm3) Flux (g N2O-N/ha/d) 160 0.40 120 0.30 80 0.20 40 0.10 0 - Aug-09 Oct-09 Dec-09 Feb-10 Apr-10 Jun-10 Aug-10 Oct-10 Urine day 1 Urine day 1 + DCD day 1 Urine day 28 Urine day 28 + DCD day 1 average SW Kelly et al. unpublished

27. Hourly N2O flux – wheat Wongan Hills (WA) 140 Wheat (+lime) Wheat 120 Fertiliser N2O Flux (ug N2O-N m h ) -1 100 -2 80 60 40 20 0 -20 Jun-09 Aug-09 Oct-09 Dec-09 Feb-10 Apr-10 Jun-10 Aug-10 Oct-10 Dec-10 Feb-11 Barton et al. unpublished

28. www.N2O.net.au Repository

29. Top 10 findings to date • Wide range in N2O emissions – 0.06 kg N/ha/annum in coarse textured soils of the WA wheat belt to > 1 kg N/ha/day from high carbon soils of SE Victoria. • Highest emissions – High rainfall pasture (dairy) systems (SE Aust.) – High rainfall residue retained cane systems (NE Aust.) – High rainfall cropping systems after pasture (SE Aust.) • Semi-arid continuously cropping systems of Australia are historically low emitters of N2O. • Irrigated cotton/cereal systems (NE Aust.) historically have low N2O emissions due to residue removal.

33. Top 10 findings to date • Nitrification inhibitor dicyandiamide (DCD) potentially reduces N2O emissions from urine deposition by 40%. • Residue retained soils in cane have sufficient C inputs to produce of CH4 if waterlogged for prolonged period. • Enhanced Efficiency Fertilizers (EEFs) have potential for reducing N2O emissions but highly variable and site specific. • Farming system history plays a highly significant roles in the magnitude of N2O emissions.

37. Top 10 findings to date • Magnitude of N2O emissions is heavily dependent on the ability to produce and retain significantly large amounts of biomass and readily decomposable carbon. • Tendency for increased inputs of carbon in irrigated and medium-high rainfall cropping systems of NE Aust. (i.e. retaining residues and use of legume N sources) will potentially increase N2O emissions.

38. Top 10 findings to date • Magnitude of N2O emissions is heavily dependent on the ability to produce and retain significantly large amounts of biomass and readily decomposable carbon. • Tendency for increased inputs of carbon in irrigated and medium-high rainfall cropping systems of NE Aust. (i.e. retaining residues and use of legume N sources) will potentially increase N2O emissions.

39. Labile carbon and N2O emissions in cropping systems 150 130 N emissions 110 N2O – without carbon 90 70 50 30 22 42 62 N rate

40. Labile carbon and N2O emissions in cropping systems 150 130 N emissions 110 N2O – without carbon 90 70 50 N2O – with carbon 30 22 42 62 N rate

41. Labile carbon and N2O emissions in cropping systems 150 130 Yield/N emissions 110 YIELD 90 70 50 N2O 30 22 42 62 N rate

42. Nitrogen Use Efficiency (Cereals)* 80 NUE 70 (kg grain/ 60 kg N applied) 50 40 30 20 10 0 2000 2001 2002 2003 2004 2005 2006 2007 2008 *FAOSTAT

43. Regional N2O Emission Potential Low Medium High No data/uncertain Grace et al. unpublished

44. Conclusions • Increased emphasis on carbon farming and a wide variety of carbon enhancing strategies (proven and unproven) will potentially have a major impact on N2O emissions. • Maintaining profitability requires an emphasis on reducing emissions intensity (GHGs/unit product) not just GHGs in isolation. • The significant variability in the impact of management practices, rotations, EEFs and nitrogen inputs across a wide range of climates and soils underscores the need for increased use of a variety of simulation modelling techniques to predict the behaviour of mitigation practices in different situations.

45. Conclusions • Increased emphasis on carbon farming and a wide variety of carbon enhancing strategies (proven and unproven) will potentially have a major impact on N2O emissions. • Productive and profitable farming requires an emphasis on reducing emissions intensity (GHGs/unit product) not just GHGs in isolation. • The significant variability in the impact of management practices, rotations, EEFs and nitrogen inputs across a wide range of climates and soils underscores the need for increased use of a variety of simulation modelling techniques to predict the behaviour of mitigation practices in different situations.

46. Irrigation management – wheat Kingsthorpe (Qld) Treatment Irrigated Optimum Dryland Average Flux 5.5 3.2 3.3 (g N2O-N/ha/day) Seasonal Flux 0.75 0.43 0.45 (kg N2O-N/ha) Emissions factor (%) 0.38 0.22 0.23 Irrigation/rain (mm) 417 315 219 Yield (t/ha) 3.1 1.9 1.6 Emissions intensity 0.25 0.27 0.33 (kg N2O-N/t yield)

49. Conclusions • Increased emphasis on carbon farming and a wide variety of carbon enhancing strategies (proven and unproven) will potentially have a major impact on N2O emissions. • Maintaining productivity & profitability requires an emphasis on reducing emissions intensity (GHGs/unit product) not just GHGs in isolation. • Variability in the impact of management practices, rotations, EEFs and nitrogen inputs across climates and soils emphasises the need for increased use of a variety of simulation modelling techniques to predict the behaviour of mitigation practices in different situations.

50. THANK YOU

Australian N2O Research Program Highlights Top Findings

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