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Nitrogen Use and Climate Change Mitigation - Daniel Kindred (ADAS)
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Nitrogen Use and Climate Change Mitigation - Daniel Kindred (ADAS)

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This presentation formed part of the Farming Futures workshop for Lincolnshire Cereals and Oilseed Growers (22 October 2008)

This presentation formed part of the Farming Futures workshop for Lincolnshire Cereals and Oilseed Growers (22 October 2008)

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  • 1. Insert image here Nitrogen Use and Climate Insert image here Change Mitigation Daniel Kindred Insert image here ADAS Boxworth www.adas.co.uk
  • 2. Outline Background – Global drivers Nitrogen – problems & benefits Optimising N for GHG mitigation Optimising N for profitability Maximising use of non-fertiliser N Nitrogen Efficient crops Biofuels & Nitrogen Conclusion - What can the grower do?
  • 3. A Changing World? Climate Change Increasing Energy demands/Reduced energy supplies Economic changes
  • 4. Agriculture driving Climate Change Agriculture contributes ~14% to global GHG emissions ~1/3 due to methane (livestock) ~23x more potent than CO2 ~1/3 due to nitrous oxide (N fertiliser) ~300x more potent than CO2 … and drives Land Use Change ~15% global emmissions Pressures/Opportunities to reduce GHGs from Agriculture Carbon trading? Carbon labelling? Biofuels/Energy crops Carbon sequestration …. Economic incentives for mitigating GHGs? Total emissions 49000Mt CO2e IPCC 2007
  • 5. GHGs from crops overwhelmed by N fertiliser Pesticide P&K Diesel Drying 10% Seed 8% Over 70% GHG emissions 5% from wheat crop can be due directly or indirectly to N fertiliser Nitrous oxide ? N fertiliser 38% 38% Sylvester-Bradley & Kindred (2008) HGCA R&D Conference
  • 6. Changing agriculture? Increasing Demand for crop products Rising population & Rising affluence, especially in SE Asia Increasing consumption of energy, petroleum, edible oils & meat Biofuels Mainly from Maize, sugar cane & palm oil Constrained supply Finite crop land globally Yield increases have slowed or stopped Diminished world stocks Weather/Climate change Floods, droughts, extreme temperatures (Increased severity of pests, disease, weeds) Crop failures Productivity shortfall
  • 7. …Drives Land Use Change Loss of habitats & biodiversity Carbon lost from soils and canopy • 5900 Mt CO2eq per year • cf aviation of <3000 Mt per year Grassland to crop – 5t CO2/ha Forest to crop – 29t CO2/ha cf crop inputs GHG costs ~3t CO2e/ha
  • 8. N fertiliser – the problem: a) Manufacture 1. Fossil Fuel intensive Haber-Bosch process H2 from Natural Gas + N2 from atmosphere = ammonia (NH3) High temperatures, high pressure 3-4kg CO2/kg N Modern plants approaching max efficiency 2. N2O released from Nitric acid production Ammonia oxidised to form Nitric acid Produce ammonium nitrate ~ 3-4kg CO2e/kg N Can be reduced by abatement technologies in some plants
  • 9. GHGs of Fertiliser products Ammonium Nitrate (AN) 30 Ammonia loss (% N applied) 7-8kg CO2e/kg N Lower from some plants? 25 Lower for most UK AN? 20 Urea ~4kg CO2e/kg N 15 but greater volatilisation and ammonia loss 10 Risk failing National Emissions Ceilings Directive (2001/91/EC) 5 Need 10-20% more fertiliser than AN 0 Urea Urea+ UAN UAN+ AN Use Urease inhibitors? Agrotain Agrotain Defra Project NT26 (Dampney et al 2006)
  • 10. N fertiliser – the problem: b) Soil N2O emissions Denitrification, some nitrification Complex microbial processes Very variable & uncertain in the field Favoured by wet warm anaerobic conditions Needs source of C and N ~6kg N2O/ha/yr ~1800kg CO2e Baseline emissions? ~2kg N2O/ha? Related to crop residues? N2O from N fertiliser additions Artificial or organic 0.021kg N2O/kg N ~6.2kg CO2e/ kg N www.farmingfutures.org.uk
  • 11. N fertiliser – the problem Leaching and volatilisation Eutrophication Water quality - WFD Nitrate Vulnerable Zones Indirect emissions of N2O from leached nitrate and volatilised ammonia
  • 12. N fertiliser – the benefits IMPROVES YIELDS - sometimes by more than double - More efficient use of other high GHG inputs - Possible sequestration benefits?? 12 Grain yield (kg/ha) 10 8 6 4 2 0 0 100 200 300 400 N applied (kg/ha) Average response curve from HGCA Project Report 438 (Sylvester-Bradley et al., 2008)
  • 13. N fertiliser – Reduces land requirement yield, t/ha land required, ha/tonne Deforestation 0 N applied, kg/ha
  • 14. N effects on GHG emissions 1200 12 GHG emissions (kg CO2 e/t) 1000 10 Operations Agrochemicals 800 8 Yield (t/ha) Grain yield 600 6 400 4 200 2 0 0 0 50 100 150 200 250 300 350 400 N fertliser applied (kg/ha) Kindred et al. (2008) In prep
  • 15. N effects on GHG emissions 1200 12 GHG emissions (kg CO2 e/t) 1000 10 N fertiliser emissions 800 Agrochemicals 8 Yield (t/ha) Operations 600 Grain yield 6 400 4 200 2 0 0 0 50 100 150 200 250 300 350 400 N fertliser applied (kg/ha) Kindred et al. (2008) In prep
  • 16. Optimising N to minimise GHGs 1200 12 GHG emissions (kg CO2 e/t) 1000 10 Soil N20 emissions 800 N fertiliser emissions 8 Agrochemicals Yield (t/ha) Operations 600 Grain yield 6 400 4 Optima to minimise GHGs? 200 2 0 0 0 50 100 150 200 250 300 350 400 N fertliser applied (kg/ha) Kindred et al. (2008) In prep
  • 17. Optimising N to minimise GHGs 1200 12 GHG emissions (kg CO2 e/t) 1000 10 Land use change Soil N20 emissions 800 8 N fertiliser emissions Yield (t/ha) Agrochemicals Operations 600 Grain yield 6 400 4 Large uncertainties in ILUC 200 calculations, depending on assumptions 2 – optima can be >300kg/ha 0 0 0 50 100 150 200 250 300 350 400 N fertliser applied (kg/ha) Kindred et al. (2008) In prep
  • 18. Optima N to minimise GHGs Depends on your views of whether what you do on your farm effects what happens elsewhere in the world If ignore LUC, then need to cut back N fert dramatically to minimise GHGs If account for LUC, may need to increase N fert, depending on the assumptions made
  • 19. Optimising N for profitability Economic optima dependent on Soil N supply Shape of response curve Price of grain and fertiliser Breakeven ratio Amount of grain needed to pay for amount of N fertiliser Grain quality
  • 20. Change in prices 500 500 15 Straight Nitrogen Straight Nitrogen Straight Nitrogen Feed Wheat price index (2000=100) price index (2000=100) Feed Wheat 400 400 break-even ratio 400 12 price index (2000=100) break-even price ratio 300 300 9 ( N:grain ) 200 200 6 100 100 3 0 0 1985 1990 1995 2000 2005 0 2010 1985 1990 1995 2000 2005 2010
  • 21. Adjusting N for BER 12 10:1 5:1 3:1 15:1 400 14:1 10 15:1 Grain yield (kg/ha) 13:1 350 12:1 8 300 11:1 AN price £/t 10:1 6 250 9:1 8:1 Economic optima 4 close to GHG 200 7:1 6:1 optima? 150 2 5:1 4:1 100 0 3:1 50 75 100 125 150 175 200 2:1 0 100 200 300 400 Grain price £/t N applied (kg/ha) 10kg/ha less per point increase in BER ~0.07t/ha decrease in yield
  • 22. Soil N Supplies Maximise use of non-fertiliser N 20% of sites in HGCA Project Report 348 did not respond to N Soil organic matter Previous crop residues Peas & Beans Animal manures/compost/sludge Atmospheric deposition Over-winter leaching ADAS Terrington
  • 23. Soil analysis: the best index of soil N 300 Look-up tables (in N uptake with nil N applied (kg/ha) RB209) being revised Measuring SMN & crop N 200 Nov. to Feb. indicates soil N supply available to the crop 100 Rarely under-estimates crop-available N New HGCA Project 0 to improve soil N 0 100 200 300 measurements. SNS from soil analysis in autumn (kg/ha)
  • 24. N efficient crops N Use Efficiency (kg DM harvested per kg crop-available N) 0 20 40 60 80 Sugar beet Potatoes - maincrop Potatoes - seed Triticale Rye Triticale instead of second Spring barley - feed wheat? Winter oats Winter wheat - feed etc. Peas/beans instead of OSR Winter barley - feed etc. – GHG free N? Spring wheat - milling Potatoes - early Possible Spring oats Winter wheat - milling intercropping/under- Spring barley - malting sowing with clover etc? Winter barley - malting Oilseed rape - winter Oilseed rape - spring Linseed Peas - harvested dry Faba beans - winter Peas - vining Sylvester-Bradley & Kindred 2008 J Exp Bot
  • 25. Consider N efficient varieties? Seems to be little difference in N requirement in modern wheat varieties Breadmaking wheats needs more N than Feed wheat Question N efficiency and profitability of growing milling wheat at high fertiliser costs (economic and environmental)? Modern higher yielding wheat have higher N optima than older varieties But, NUE at optima no different Higher yielding varieties less GHG per t Modern spring barley varieties higher yielding, but optima not higher than older varieties HGCA Project Report 438 – Sylvester-Bradley et al 2008
  • 26. GREEN grain project Genetic Reduction of Energy use and Emissions of Nitrogen through cereal production Facilitate breeding of varieties that require less N fertiliser and are suitable for distilling, bioethanol and animal feed Cheaper to grow Greater end-use value Reduced N pollution GHG & Energy savings for bioethanol
  • 27. Breeding oilseed rape with a low requirement for nitrogen fertiliser Primary Objective Northeast Biofuels Breed varieties which require half of Elsoms Seeds the N fertiliser of current varieties www.adas.co.uk
  • 28. Breeding for N capture: new innovations Biological Nitrification inhibitors Root exudates can inhibit soil conversion of ammonium to nitrate Useful with urea fertilisers Stops leaching in wet soils CIMMYT, Mexico GM technology – faster ammonium assimilation Alanine aminotransferase OSR: 50% N required Now being transferred to rice, maize & wheat Arcadia Biosciences, CA
  • 29. Consider growing biofuels? Biodiesel – OSR Bioethanol – wheat/sugar beet Displace petrol/diesel Reduce GHG emissions But, over 50% of GHG intensity of biofuel comes from growing the crop Need to minimise GHG emissions from growing crop Need low inputs… And high yield!!! N strategy very important for growing Biofuel crops
  • 30. An ‘ideal’ biofuel wheat field-dry Minimum grain ... non-starch Minimum Nitrogen High Inputs yields 50% lots of >70% starch GH straw Ea Sav G sy ac c ed Efficient processing r Low land ed i requirements tatio n
  • 31. Nitrogen for biofuels 12 236 13 Grain N x 5.7 (% DM) 10 12 (t/ha @ 85%DM) Grain yield 500 8 8.6% 11 6 protein 10 Alcohol yield (litres / tonne, dry basis) 480 4 9 2 8 460 0 7 5,000 0 100 200 300 470 184 yield (litres / dry tonne) Alcohol production Alcohol processing 440 4,000 N applied (kg/ha) 460 (litres/ha) 3,000 420 450 2,000 440 1,000 400 4 6 8 10 12 14 16 18 0 430 grain protein (%, dry basis) 8,000 0 100 200 300 Greenhouse Gases N applied (kg/ha) (kg CO2 eq per ha) total saving Reduced protein = increased biofuel 6,000 91 cost 4,000 2,000 net saving 0 0 100 200 300 N applied (kg/ha)
  • 32. Improving N efficiency Targets: N capture Rooting Soil N ‘processing’ N assimilation N utilisation crop N storage canopy N activity oilseed photosynthesis etc. wheat rape Breeders and testers have used ample nutrients Now we must minimise crop ‘profligacy’ & ‘gluttony’
  • 33. Cultivations & straw Minimising fuel use No grain drying saves ~0.2 t/ha/yr CO2e early ripening crops ample combine capacity Minimum tillage saves ? ~0.6 t/ha/yr CO2e Can increase N2O? Straw disposal ? Incorporation saves ? ~0.7 t/ha/yr CO2e Bale, cart and use for fuel saves ? ~2.0 t/ha/yr CO2e
  • 34. Conclusions – Mitigating climate change on-farm Buy low GHG intensity fertiliser? Urea rather than AN? Use Urease inhibitors? Avoid applying more than the economic optimum This may be lower than you think! Make full use of non-fertiliser N Use SMN testing where appropriate Make full allowance of N in muck/sludge/compost etc Allow for N after peas & beans/potatoes/veg etc
  • 35. Conclusions – Mitigating climate change on-farm Consider changes to crops/ rotations Grow cereals with lower N requirements – oats & triticale Grow more legumes/less OSR Use of fertility building leys/undersowing/inter-cropping? Grow biofuels? Nitrogen use will be important Breeding likely to provide more N efficient varieties 5-10 years +
  • 36. Thankyou
  • 37. Developing N efficiency testing N efficiency yield RL trials breeding breeding RB209 N levels some 1st wheats 10 + 80 kg/ha N grain yield (t/ha) HGCA N-opts 8 Yield breeding: control + 15-20 kg N / t 6 NUE breeding 4 Needs low-N testing 2 0 0 100 200 300 N applied (kg/ha)
  • 38. Developing yields Light limit for UK wheat, 19 t/ha 18 On-farm No increase for >10 years Grain yield (t/ha, 3-year means) 16 Water limit Recommended varieties Increasing: 0.7 tonne / ha / decade 14 Possible causes Economics: low prices, cost cutting 12 Climate change ? new varieties in RL trials Technology gap ? 10 Can yields respond fast enough to farms cancel extra land requirements ? 8 6 4 1970 1990 2010
  • 39. UK agriculture: Nitrogen efficiency N inputs .. 1.8 Mt/year Deposition Imports in feeds Denitrifica- Food & Fixation tion Fertilisers materials Sewage Nitrate leached Ammonia N outputs .. 1.8 Mt/year
  • 40. UK agriculture: Nitrogen legislation Climate Change Nitrate & Water measures Framework Directives Denitrifica- Food & tion materials EC National EC National Nitrate leached Emission Ceilings Emission Ceilings Ammonia Directive Directive N outputs .. 1.8 Mt/year
  • 41. 14 UK wheat: efficiency 12 Grain yield (t/ha, 3-year means) 10 Potential UK yields are over 14 t/ha 8 6 4 Breeders increasing yields by 0.7 t/ha 2 per decade 0 1970 1980 1990 2000 2010 No yield increase on-farm for >10 years
  • 42. UK wheat: efficiency 200 100 No increase in N applied 0 1970 1980 1990 2000 2010 3.0 2.5 No trend in 2.0 grain N% 1.5 1.0 1970 1980 1990 2000 2010
  • 43. Nov / Jan: N management on- AssessMar: N Feb / soil farm example: wheat &ApplyNApril: plan 40rates Early kg/ha except if: st half Apply 1 Late April / .. of canopy N high soil N early May: Late May: .. too many shoots .. high lodgingN half Apply 2nd for Apply risk July: .. low take all riskN of canopy high yields /N to spray urea After harvest: …protein boost but adjust boost proteins? according to yields Review canopy& grain yield …… depends on if expected size N% over 9 t/ha premiums, yields, & … Were rates about past proteins right? … Adjust N strategy?
  • 44. Products: N efficiency Ammonia Emissions 10 cereal trials 30 Ammonia loss (% N applied) 25 20 15 10 5 0 Urea Urea+ UAN UAN+ AN Agrotain Agrotain
  • 45. N efficiency : effect of high prices ? Break-even ratios 10 (kg grain per kg N) 13 7 5 3 1 8 12 Yields only 6 slightly less 11 grain yield grain protein (t/ha) lower (N x 5.7, % ) 4 proteins 10 optimums 2 9 0 8 0 100 200 300 N applied (kg/ha)
  • 46. Setting N rates 50 recent HGCA trials Recommended N (difference from optimum) kg / ha -200 -100 0 100 200 £0 Average -£50 -9 kg/ha N -£14/ha -£100 Net profit £ / ha -£150
  • 47. Late N, to boost protein – 9 HGCA trials 14 Foliar urea 10% Foliar urea 20% AN + urea 10% grain protein (%) AN + urea 20% 13 AN at GS39 12 11 0 40 80 120 extra late N (kg/ha)
  • 48. Late N, to boost protein – 9 HGCA trials 16 Boxworth 2003 Essex 2005 15 Rosemaund 2003 High Mowthorpe 2004 14 grain protein (%) Boxworth 2004 13 Terrington 2004 High Mowthorpe 2005 12 Rosemaund 2004 Terrington 2003 11 10 New HGCA 9 research 8 to predict 0 40 80 120 protein extra late N (kg/ha)
  • 49. Reviewing Farm N efficiency Applying N cannot be accurate on every field every year But avoid cumulative errors Important for profit & environment To monitor overall N strategy, check: Soil mineral N Canopy sizes nil N patches ? Grain N% … above or