1. Reducing Nitrogen Losses from Agriculture Using a Nitrification Inhibitor (eco-n) Professor Keith Cameron, Professor Hong Di and Dr Jim Moir Centre for Soil and Environmental Quality Lincoln University, Canterbury New Zealand

2. Two main nitrogen losses from agriculture Nitrate leaching in drainage water causes pollution of surface and groundwater Nitrous oxide (N 2 O) is given off by soil and is a potent greenhouse gas. NZ agricultural greenhouse gases

3. How do you measure nitrate leaching losses from a grazed pasture?

4. Collecting 1- tonne Templeton soil lysimeters

5. Underground laboratory constructed to house lysimeters under typical soil and environmental conditions

6. Surface of lysimeters level with surface of paddock. Typical rainfall, temperature, irrigation, fertiliser, pastures, and urine applied.

7. Going downstairs into the underground laboratory

8. Drainage water is collected in the underground laboratory to measure nitrate leaching losses directly from soils.

9. Robotic cow hoof used to simulate trampling during grazing

10. Results show that in dairy farming urine patches are the main sources of nitrate leaching and nitrous oxide emissions

11. Most nitrate leaching comes from urine patches not from fertiliser Ledgard et al, 2005

12. Improved nitrogen management is now possible with the newly developed eco-n nitrification inhibitor.

13. NH 4 + - - NO 3 - Cation exchange Nitrate ions (NO 3 - ) are not held by soil particles and can easily be leached when drainage occurs The Nitrogen Cycle (McLaren & Cameron, 1996)

14. NH 4 + - - NO 3 - Cation exchange Nitrification inhibitor ‘eco-n’ slows down the rate of nitrate production and thus reduces the nitrate leaching loss The Nitrogen Cycle (McLaren & Cameron, 1996)

15. The inhibitor temporarily reduces the activity of the nitrosomonas bacteria in the soil (Bacteriostatic effect)

16. Nitrification inhibitor (‘eco-n’) is applied as a fine suspension spray to improve soil N cycle efficiency and reduce the risk of nitrate leaching

17. Eco-n is applied in May and July/August because most losses occur between late autumn and early spring Drainage eco-n

18. HAMILTON: Mean Soil Temperatures (at 10 cm) and Estimated Drainage (mm) 0 20 40 60 80 100 120 JanFebMarAprMayJunJulAugSepOctNovDec Months Estimated Drainage (mm) 0 2 4 6 8 10 12 14 16 18 20 Soil Temperature ( 0 C) Drainage Soil Temp (C) Drainage eco-n In North Island Eco-n is applied in May and July because leaching also occurs in the winter/early spring

19. Nitrate leaching

20. Eco-n applied twice (May plus August) reduced the nitrate concentration from urine applied in May (Templeton soil) (Di and Cameron, 2004. NZ J Agr. Res. 47) Urine only Urine plus eco-n (May + Aug)

21. Eco-n reduced the nitrate leaching loss by 76% (Templeton soil) (Di and Cameron, 2004). Urine only Urine plus eco-n (May + Aug)

22. Eco-n reduced nitrate leaching by 30 – 40% 3 year trial shows that eco-n inhibitor significantly reduced nitrate leaching losses from Taupo pumice soils

23. Nitrous oxide greenhouse gas emissions

24. Nitrous oxide gas emissions are measured using gas chambers placed on the lysimeters for 30 minutes each day.

25. Source: National Inventory Report: 1990-2003 (Ministry for the Environment, April 2005)

26. Eco-n reduced N 2 O emissions by 73% on Templeton soil in Canterbury, NZ (Di et al. 2007).

27. Eco-n reduced N 2 O emissions by 61% in the Waikato Horotiu soil (Di et al., 2006) eco-n

28. National Inventory Report: 1990-2005 (Ministry for the Environment, April 2007) 2005 scenarios NZ’s Agricultural nitrous oxide emissions reduced with ‘eco-n’

29. Pasture production

30. Lincoln University Control plot: no ‘eco-n’ Lincoln University ‘eco-n’ plot Retaining More Nitrogen in the Soil Produces More Pasture Growth

32. Average Annual Pasture Yield – LUDF South Block 4 Years - 2002/03 to 2005/06 Seasons Moir et al., 2007

33. Equally high ME with eco-n

34. Conserving N with the inhibitor grows more pasture (Moir et al. 2007)

35. Summary

36. Decrease in nitrous oxide emissions Increase in annual farm pasture production Decrease in nitrate leaching Research results show:

37. Eco-n is based on New Zealand research trials published in internationally peer reviewed science journals 1.Di HJ and Cameron KC (2002) Soil Use and Management 18: 395-403. 2.Di HJ and Cameron KC (2003) Soil Use and Management 19: 184-290. 3.Di HJ and Cameron KC (2004a) Soil Use and Management 20: 2-7. 4.Di HJ and Cameron KC (2004b) NZ Journal of Agricultural Research 47: 351-361. 5.Di HJ and Cameron KC (2004c) Australian Journal of Soil Research 42: 927-932. 6.Di HJ and Cameron KC (2005) Agriculture, Ecosystems and Environment 109: 202-212. 7.Di HJ and Cameron KC (2006) Biology and Fertility of Soils 42: 472-480. 8.Di HJ, Cameron KC and Sherlock (2007) Soil Use and Management 23: 1-9. 9.Moir JM, Cameron KC and Di, HJ (2007) Soil Use and Management 23: 111-120. 10.Clough TJ, Di HJ, Cameron KC, Sherlock, RR, Metherell AK, Clark H and Rys, G (2007) Nutrient Cycling in Agroecosystems 78: 1-14. 11.Di HJ and Cameron KC (2007) Nutrient cycling in Agroecosystems 79,281-290. 12.Di HJ and Cameron KC (2008) Australian Journal of Soil Research 42: 927-932.

38. Lincoln University would like to thank Ravensdown Fertiliser Co-operative Ltd, and the Pastoral Greenhouse Gas Research Consortium (PGGRC) for funding this research.