Nitrous oxide emissions from urine and dung Dave Chadwick Laura Cardenas, Neil Donovan, Tom Misselbrook, John Williams, Rachel Thorman, Karen McGeough, Catherine Watson, Madeleine Bell, Steve Anthony, Bob Rees
Content Context UK GHGPlatform Urine & Dung experiments Methods Results Synthesis Summary
Urine and dung - sources of N 2 O Grazing livestock convert pasture biomass N into N r Urine and dung deposition represent hotspots of N (300-1000 kg/ha N in a pat(ch)) IPCC default N 2 O EF (2006 GL): 2% (cattle), 1% (sheep) Pasture, Range and Paddock represents significant proportion of total N 2 O from national agricultural emission inventories 25% 13% 1% 22% 5% 0% 1% 6% 9% 13% 5% N 2 O emissions UK agriculture (2013). Total 71.5 kt Histosols Field burning Mineralisation Atmospheric deposition Manure management systems Animal manure applied to soil Crop residues Grazing Synthetic fertilisers Leaching and runoff
Luxemburg Slovenia Iceland Estonia Croatia Latvia Norway Austria Slovakia Portugal Lithuania Hungary Sweden Bulgaria Belgium Finland Greece Czech Republic Denmark Romania Netherlands Ireland New Zealand Japan Kazakhstan Italy Poland Australia Turkey Ukraine UK Spain Germany France Russia National N 2 O emission (kt/yr) Grazing as % total N 2 O emission Grazing as % of total agriculture N 2 O emission from different nations (UNFCCC, 2016 - year 2013) 300 70 250 60 200 50 150 40 30 100 20 50 10 0 0 % of total agricultural N 2 O emitted from grazing varies between nations depends on livestock systems (housing vs grazing period)
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Mt CO 2 e / year Trends in UK GHG emissions from agriculture (IPCC 2006 Guidelines) 35 30 25 20 15 10 5 0 Methane Nitrous oxide N 2 O Tier 1 with CS activity data (N excretion, livestock numbers, fertiliser use) CH 4 Tier 2 for enteric emissions for dairy cattle, other Tier 1 with CS data on livestock numbers, distribution of MMS
Why change to a Tier 2 approach? UK set challenging targets Industry GHG roadmaps Tier 1 is a blunt reporting tool Need a reporting tool that better reflects: Soil types & Rainfall zones Management of nitrogen sources Management of grassland and livestock (diet, breed, upland/lowland) Specific mitigation strategies Apportion uncertainty to specific parts of the inventory
UK GHGPlatform Nitrous oxide Data synthesis Methane New inventory structure
Nitrous oxide (InveN 2 Ory) project - N sources N sources Nitrogen fertilisers (ammonium nitrate and urea) Livestock manures (slurry, FYM, poultry manure) Urine & dung (grazing) N management Rate of application (fertiliser N) Timing of application (manures, urine) Method of application (slurry) Mitigation Nitrification inhibitor More frequent, smaller doses of N fertiliser Cardenas et al. (2010)
InveN 2 Ory network of experimental sites Represent the principle geoclimatic zones that support agricultural production in the UK Address the gaps identified in the initial analysis of current/recent research which has generated IPCC compliant emission factors 9 sites: 5 grass and 4 arable
InveN 2 Ory urine & dung treatments 5 treatments: Dung Urine Synthetic urine Urine + DCD Control 3 blocks 5 static chambers/plot Dung and real urine: Collected from dairy cattle < 7 days prior to experiment Synthetic urine: Recipe (Kool et al., 2006) Mean application rates (for all sites): Urine: 455 kg N ha -1 Dung: 855 kg N ha -1
InveN 2 Ory field experiments - Urine and dung *Chadwick et al. (2014) Common experimental protocol (plot layout, treatments, method of application, chamber deployment*, data processing) Urine and faeces applied to plots separately Nitrification inhibitor (DCD) mixed with urine at equivalent rate of 10 kg / ha 5 sites, spring, summer and autumn applications, 15 experiments in total
Results site characteristics Site Clay content (%) Soil ph Average annual rainfall (mm)* Average annual air temp. ( o C)* Crichton 15 5.6 1244 8.8 Hillsborough 23 5.9 1140 8.2 Pwllperian 30 5.6 1869 10.4 Drayton 59 7.6 756 11.2 North Wyke 37 5.7 1253 9.7 *Annual rainfall and air temperature of the experimental periods
Crichton - SP Crichton - SU Crichton - AU Drayton - SP Drayton - SU Drayton - AU Hillsborough -SP Hillsborough -SU Hillsborough - AU North wyke -SP North wyke - SU North wyke - AU Pwllpeiran - SP Pwllpeiran - SU Pwllpeiran - AU Creatanine /Allantoin concentration (mg/l) Hippuric acid (mg/l) DM (%) and ph Total N and Urea-N (g/l) Results urine composition 10 8 6 4 DM ph 12.0 10.0 8.0 6.0 4.0 Total N Urea-N 2 2.0 0 0.0 5000 4000 3000 2000 1000 0 Allantoin Creatinine 10000 8000 6000 4000 2000 0 Hippuric acid
Results N 2 O emissions (site level) North Wyke N 2 O flux (g N 2 O-N ha -1 d -1 ) N 2 O flux (g N 2 O-N ha -1 ) 800.0 Spring application 700.0 600.0 500.0 400.0 300.0 200.0 100.0 N 2 O lost as % of N applied 0.0-100.0 EF Urine 2.96 Urine + DCD 1.00 Artificial urine 2.23 Dung 0.14 16,000 14,000 12,000 10,000 8,000 6,000 Control Urine Urine + DCD Artificial Urine Dung 05-May 24-Jun 13-Aug 4,000 02-Oct 21-Nov 10-Jan 01-Mar 20-Apr 09-Jun 2,000 0 Control Urine Urine + DCD Artificial Urine Dung
N 2 O EF (%) Results summary data 1.6 Effect of application timing (across all sites) on N 2 O EFs 1.4 1.2 1.0 b b 0.8 0.6 0.4 0.2 a a ab a a b ab a a a 0.0 Early Mid Late Early Mid Late Early Mid Late Early Mid Late Urine Artificial urine Dung Urine+DCD Urine Urine Urine Artificial Urine Artificial Urine Artificial Urine Dung Dung Dung Urine+DCD Urine+DCD Urine+DCD Means with different letters within each treatment are significantly different (P<0.05)
Crichton Drayton Hillsborough North Wyke Pwllpeiran Crichton Drayton Hillsborough North Wyke Pwllpeiran Crichton Drayton Hillsborough North Wyke Pwllpeiran Crichton Drayton Hillsborough North Wyke Pwllpeiran N 2 O EF (%) Results summary data Site differences in N 2 O EFs (across all timings) 2.4 2.0 1.6 1.2 0.8 0.4 0.0 IPCC default N 2 O EF for cattle excreta (PRP) b b ab ab ab ab a b a ab a ab a ab b ab ab b a a UrineUrineUrineUrineUrine Artificial Artificial urine Artificial urine urine Artificial urine urine DungDungDungDungDung urine Urine Urine + DCD Urine + Urine+DCD + + DCD + DC Means with different letters within each treatment are significantly different (P<0.05)
InveN 2 Ory combined excretal (urine + dung) EF = 0.57-0.59* *depends on proportion of N excreted in urine vs dung (75:25 or 80:20) Results - synthesis N 2 O EF (%) average standard error Urine (15) 0.69 0.12 Urine + DCD (15) 0.37 0.06 Dung (15) 0.19 0.02 Recent NZ data Kelliher et al (2014) Topography Urine N 2 O EF Dung N 2 O EF Dairy Lowland 1.16 (55) 0.23 (20) Dairy Hill (low slope) 0.84 (16) 0.20 (4) Beef Hill (low slope) 0.99 (4) 0.21 (12) Beef Hill (medium slope) 0.32 (4) 0.06 (4) Sheep Lowland 0.55 (4) 0.08 (12) Sheep Hill (low slope) 0.40 (12) 0.11 (8) Sheep Hill (medium slope) 0.16 (8) -
Relationships statistical models Urine N 2 O EF = f Ammonium-N, Creatinine, Urea-N r 2 =0.724 r 2 =0.864 if air temperature and rainfall included Dung N 2 O EF = f Rainfall, %Clay, %DM, %WFPS, SOC, BD, soil ph, ph r 2 =0.688 Urine N 2 O EF predominantly controlled by urine composition Dung N 2 O EF predominantly controlled by physical environment
Wider synthesis - additional data sets UK InveN 2 Ory 15 experiments + UK additional 2 experiments + Irish - 12 new experiments - Agricultural Greenhouse Gas Research Initiative (AGRI-I) +? e.g. New Zealand (Kelliher et al., 2104)
Summary Urine and dung N 2 O emissions vary across sites and seasons Urine N 2 O EF of 0.69% significantly greater than that for dung (0.19%) Produce a combined excretal EF for cattle of 0.57-0.59%, which is much lower than IPCC default (2% cattle and 1% sheep).implications DCD efficacy variable but with average reduction of 38% from urine (range 0-75%)
Understanding what controls efficacy of inhibitors Future research Sheep urine/dung (assume the same N 2 O EF as for cattle)? Effect of stocking density urine patch overlap? Upland soils / extensive systems e.g. acid soils, cooler/wetter soils, reduced palatability of vegetation Uplands-N 2 O Mitigation strategies (manipulate urine composition and/or livestock movement, targeted use of inhibitors)
Thanks!! Organisers of the GGAA2016 Conference InveN 2 Ory project field and lab teams Dr Dan Dhanoa (statistics) Funders
Literature cited Chadwick, D.R., Cardenas, L., Misselbrook, T.H., Smith, K.A., Rees, R.M., Watson, C.J., McGeough, K.L., Williams, J.R., Cloy, J.M., Thorman, R.E. and Dhanoa, M.S. (2014) Optimizing chamber methods for measuring nitrous oxide emissions from plot-based agricultural experiments. European Journal of Soil Science 65, 295 307. Kelliher, F.M., Cox, N., van der Weerden T.J., de Klein, C.A.M., Luo J. and Cameron, K.C. (2014) Statistical analysis of nitrous oxide emission factors from pastoral agriculture field trials conducted in New Zealand. Environmental Pollution 186, 63-66. Kool, D.A., Hoffland, E., Sander, A. and van Groenigen, J.W. (2006) What artificial urine composition is adequate for simulating soil N 2 O fluxes ands mineral N dynamics. Soil biology and Biochemistry 38, 1757-1763. UNFCCC (2016) National greenhouse gas emission submissions for the year 2013. http://unfccc.int/national_reports/annex_i_ghg_inventories/national_inventories_sub missions/items/8812.php [accessed on 11th January 2016)