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Nitrous oxide and the NZ ETS

Nitrous oxide and the NZ ETS. Prof. Tim Clough. IPCC AR4.

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Nitrous oxide and the NZ ETS

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  1. Nitrous oxide and the NZ ETS Prof. Tim Clough

  2. IPCC AR4

  3. Comparison of annual N2O ODP-weighted emissions from the 1990s [IPCC, 2007 (18, 23)] with emissions of other ozone-depleting substances in 1987, when the emissions of chlorine- and bromine-containing ODSs were near their highest amount, and for 2008. (Ravishankara et al. 2009, Science) N2O → N2 + O N2O + O → 2NO NO + O3 → NO2 + O2 O + NO2 → NO + O2 net: O + O3 → 2O2

  4. Between 1860 to 2005 Davidson (2009) suggests that roughly 2.0% of annual manure-N production and 2.5% of fertilizer-N production have been converted to N2O…these percentage contributions explain the entire pattern of increasing nitrous oxide concentrations over this period Nature Geoscience 2, 659 - 662 (2009)

  5. Wrage et al. 2001 Soil Biol. & Biochem. Nitrification

  6. Wrage et al. 2001 Soil Biol. & Biochem. Nitrifier-Denitrification

  7. Need to reduce agriculture’s impact on climate change • Greenhouse gas (GHG) emissions: • Agriculture accounts for 50% of NZ’s total GHG. • Nitrous oxide (N2O) has a global warming potential 298 times greater than CO2 over a 100 year period. Greenhouse gas emissions from NZ agriculture Nitrous oxide 34% (27% > 1990 levels) Methane 64% (10%>1990)

  8. In grazed pastures urine patches are the main sources of nitrous oxide emissions and nitrate leaching 1,000 kg N/ha in urine patch ( = 2 t Urea/ha) Urea fertiliser only applied at 30 kg N/ha

  9. What can we do about N2O?

  10. Covered feed & loafing pad (Cecile De Klein, AgResearch)

  11. Low-nitrogenpastureplants • A major new research programme is among the first to be funded by the New Zealand Agricultural Greenhouse Gas Research Centre. • Led by Dr Susanne Rasmussen, it focuses on the feasibility of growing high-yielding pasture species with a lower nitrogen content. • If results prove that growing the species will be viable, this would open up the possibility of farmers being able to maintain pasture productivity while reducing the amount of nitrogen excreted. • The outcome would be multiple environmental benefits, for example a reduction in greenhouse gas emissions. Low-nitrogen plants would also address the problem of nitrogen leaching into waterways, helping to improve water quality

  12. Nitrification rate is related to Ammonia Oxidising Bacteria (AOB) population(Di et al., 2009. Nature Geoscience: 2: 621-624 )

  13. Nitrification inhibitor temporarily blocks the active site of a specific enzyme (ammonia monooxygenase) inhibitor

  14. Nitrification inhibitors can reduce nitrous oxide emissions and nitrate leaching N2O NH4+ - - - - Cation exchange Nitrification inhibitor slows down the rate of nitrate production and thus reduces the nitrogen losses NO3-

  15. Nitrification inhibitor thus restricts ammonia oxidising bacteria (AOB) population growth in soil (Di et al., 2009. Nature Geoscience: 2: 621-624 )

  16. AOB activity data show response to urine and inhibition by DCD nitrification inhibitor(Di et al., 2009. Nature Geoscience: 2: 621-624 )

  17. Nitrification inhibitor reduces the nitrate concentration in soil(Di et al., 2009. Nature Geoscience: 2: 621-624 )

  18. CHRISTCHURCH: Mean Soil Temperature (at 10cm) and Estimated Drainage (mm) 50 20 45 18 40 16 35 14 0 30 12 Estimated Drainage (mm) Soil Temperature 25 10 20 8 15 6 10 4 Drainage (mm) 5 2 Soil Temp (C) 0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Months Inhibitor is applied in April/May and Julybecause most leaching occurs in the winter/early spring inhibitor inhibitor

  19. Nitrous oxide gas emissions from gas chambers placed on lysimeters for a standard 40 minutes each day.

  20. DCD reduced N2O emissions by 81% in the Waikato Horotiu soil (Di et al., 2010)

  21. A consolidated table of all NZ published data on N2O reductions by DCD (de Klein et al. 2011) . • Data from over 45 New Zealand trials under a wide range of soil, environment and management conditions. • The average N2O reduction with DCD was 57% ( 3.1). 57% ( 3.1)

  22. http://www.maf.govt.nz/news-resources/news/more-accurate-science-improves-agriculture%E2%80%99s-greenhttp://www.maf.govt.nz/news-resources/news/more-accurate-science-improves-agriculture%E2%80%99s-green “The United Nations Framework Convention on Climate Change (UNFCCC) Expert Review Team commended New Zealand for incorporating the effect of the nitrification inhibitor, dicyandiamide (DCD), into its country-specific emissions factors, as DCD represents a potentially significant mitigation option that may gain increased use over time”

  23. Nitrate leaching losses

  24. Soil lysimeter facilities in different regions Waikato: Horotiu soil Canterbury: Templeton and Lismore Taupo pumice soil

  25. DCD reduced nitrate leaching from a Canterbury Lismore soil (Di et al., 2009)

  26. Nitrate leaching losses reduced in a range of South Island soils (Di et al. 2009) Urine only Urine plus eco-n (May + Aug)

  27. Nitrate leaching losses reduced inNorth Island Soils Data from Shepherd et al. 2009 (AgResearch). FLRC Conference Proceedings. Urine only Urine plus eco-n (May + Aug)

  28. AgResearch study showed DCD reduced nitrate leaching lost by between 21 and 56%,depending on the year of study (P < 0.05) (Monaghan et al. 2009. NZJ Agricultural Research 52; 145-159)

  29. FertResearch Fact Sheet #11 “Nitrification Inhibitors” Paddock scale reduction in nitrate leaching PER HECTARE PER YEAR 10-30% North Island 25-40% South Island http://www.fertresearch.co.nz/code-of-practice/fact-sheets

  30. DCD degradation and soil temperature NZ data International literature (4 studies) Kelliher & Clough et al. Soil Biol. Biochem. 2008

  31. Inhibitor effects on other soil microbes?AgResearch study concluded that: • “DCD had little impact on the overall soil bacterial activity. • In contrast the microbes targeted by DCD, the ammonium-oxidising bacteria, were significantly affected by DCD with reductions in population size and altered activity. • The results suggest that application of DCD to pasture is a relatively benign intervention that has an important role to play in mitigating the environmental hazards imposed by ongoing land use intensification.” (O’Callaghan et al. 2010)

  32. Pasture Production

  33. Retaining more nitrogen in the soil can produce more pasture growth Lincoln University Control plot: no ‘eco-n’ Lincoln University ‘eco-n’ plot

  34. National Trial Series shows significant increases in pasture growth from dicyandiamide. (132 data sets from 37 large on-farm grazed pasture trials) Carey et al. (2011).

  35. Thank you

  36. Calculating DCD emission factors (EF) kg N2O/kg fertiliser-N kg N2O/kg excreta-N (Clough et al. 2007 Nutr. Cycl. Agroecosyst. 78:1-14. )

  37. Effect of eco-n on N2O inventory

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