Organic fertilization as a mitigation option: ammonia and nitrous oxide emissions

Transcription

1 International Workshop: Greenhouse Gas Emission from Oilseed Rape Cropping and Mitigation Options Organic fertilization as a mitigation option: ammonia and nitrous oxide emissions Thomas Räbiger Monique Andres, Katharina Kesenheimer, Sarah Köbke, Hannes Hegewald, Teresa Suarez, Roland Fuß

2 Introduction Substitution of mineral N fertilizer by organic N fertilizer N efficiency? Gaseous N losses? Different calculation rules for GHGemissions? Accounting period/residual effects? 2

3 Introduction Substitution of mineral N fertilizer by organic N fertilizer N efficiency? Gaseous N losses? Different calculation rules for GHGemissions? Accounting period/residual effects? 2

4 3 Introduction N Efficiency of organic fertilizers Generally lower than mineral N

5 Yield (t ha -1 ) Introduction N Efficiency of organic fertilizers Fertilization total N-based 3 x split application 7 treatments: (0/0/0) (80/80/80) organic N (pig slurry) mineral N (CAN) N fertilisation (kg total N ha -1 ) Yield data: field trial at Hohenschulen ( ) (Sieling et al., 2014) 4

6 5 Introduction N Efficiency of organic fertilizers Generally lower than mineral N 2 major N components: N bound in organic fraction Plant available only after mineralization Risk of N leaching after harvest Ammoniacal N (NH 4+ ) N loss via Ammonia volatilization Indirect N 2 O emission

7 Introduction Ammonia volatilization: main factors Fertilizer properties Total ammoniacal nitrogen ph-value Dry matter content Weather after application Air temperature Wind speed Rain events Application technique 6

8 7 Introduction Fertilizer properties: cattle slurry vs. biogas digestate Parameter Ammoniacal nitrogen Cattle slurry* Biogas digestate 58% 55% ph-value Dry matter content *Source: Vandre & Clemens (1996) 9.0% 7.5%

9 NH 3 loss [% NH 4 -N ] Introduction Fertilizer properties: cattle slurry vs. biogas digestate Parameter Ammoniacal nitrogen Cattle slurry* *Source: Vandre & Clemens (1996) Biogas digestate 58% 55% ph-value Dry matter content 9.0% 7.5% 45% NH 3 - loss Higher ammonia emission potential of biogas digestate! ph ph 8.2 (modified after Jarvis and Pain, 1990)

10 NH 3 -loss [% broadcast] Introduction Application technique Ammoniakverlust [% Verlust Breitverteiler] Breitverteiler broadcast trail hoses trailing shoes Schleppschlauch Schleppschuh Applikationstechnik Injektion injection (modified after Steffens and Lorenz 2011) 8

11 Introduction Substitution of mineral N fertilizer by organic N fertilizer N efficiency? Gaseous N losses? Different calculation rules for GHGemissions? Accounting period/residual effects? 9

12 Introduction Calculation rules for GHG emissions in Europe Biograce Standard calculation tool for biofuel GHG emissions No GHG emissions for organic N fertilizer production (RED) Residual effects of organic N components are considered and calculated different time horizon between annual measurement and biograce calculation 10

13 Introduction Calculation rules for GHG emissions in Europe Direct N 2 O emission: 1% of N input (fertilizer + crop residues) Indirect N 2 O emisson: Ammonia volatilization Mineral: 10% of total fertilizer-n Organic: 20% of total fertilizer-n 1% of ammonia volatilization as indirect N 2 O N-leaching: 30% of N input (fertilizer + crop residues) 0.75% of N leached as indirect N 2 O 11

14 Material & Methods 15

15 Project description Oilseed rape wheat barley Randomized block design N fertilizer levels: Oilseed rape Mineral N (CAN): 0, 60, 120, 180, 240 kg N ha -1 yr -1 Biogas digestate: 180 kg NH 4 -N ha -1 yr -1 (total N: 330 kg N ha -1 yr -1 ) (without and with nitrification inhibitor (NI)) Wheat & barley: site-specific N fertilization Grassland (0 kg N ha -1 yr -1 ) as reference system 13

16 14 N 2 O emissions Manual chambers Flux measurements: Starting in late 2012 / early 2013 weekly intervals Event specific intensive measurement campaigns

17 NH 3 -Measurement Method: NH 3 -Measurement Dräger Tube method Period: 3-5 days after fertilization Unfertilized OSR as reference 1 replicate Automatic pump (Pacholski et al. 2006) 15

18 16 NH 3 -Measurement Dräger-tube-method Measuring NH 3 concentration of defined air volume flowing through the chambers Calculation of NH 3 fluxes depending on actual weather data

19 Results NH 3 flux example Ammonia emission N 2 O emission Yield Calculated GHG-emissions for cultivation () 17

20 Accumulated NH 3 -Nloss [kg N * ha] 18 NH 3 flux example Site: Hohenschulen Day of fertilization: Air temperature: 12 C; wind speed: 6 m*s Time after application [h] 90 kg NH 4 -N 90 kg NH 4 -N +NI

21 Accumulated NH 3 -Nloss [kg N * ha] 18 NH 3 flux example Site: Hohenschulen Day of fertilization: Air temperature: 12 C; wind speed: 6 m*s Time after application [h] relative N loss [% total N] 15% 16.4% 90 kg NH 4 -N 90 kg NH 4 -N +NI

22 Ammonia emissions Approx. 43 kg NH 3 -N-loss (relative loss: 13% total N) Lower losses after rainfall (Hohenheim; Merbitz 2013) 19

23 N 2 O emissions Very low N 2 O emissions Only marginal differences between mineral and organic fertilizers Only marginal effects of nitrification inhibitor Residual effects? 20

24 Yields Moderately lower yields with organic fertilization Exception Bornim: significantly lower yields in organic treatments No yield advantage with nitrification inhibitor 21

25 Yield (t * ha -1 ) Yield response curve OSR Hohenschulen CAN biogas digestate biogas digestate +NI n = 20 R 2 = 0,91 *** RMSE = 0,2546 t/ha N fertilization (kg mineral N ha -1 ) 22

26 Specific GHG-emission [gco 2 -eq./mj] Calculated GHG emissions for cultivation () Hohenschulen, experimental year kg N 180 kg N(CAN) 180 kg NH4-N (BD) 180 kg NH4-N (BD+NI) direct N2O indirect N2O vol indirect N2O leach fertilizer production remaining emission 23

27 Specific GHG-emission [gco 2 -eq./mj] Calculated GHG emissions for cultivation () Hohenschulen, experimental year kg N 180 kg N(CAN) 180 kg NH4-N (BD) 180 kg NH4-N (BD+NI) direct N2O indirect N2O vol indirect N2O leach fertilizer production remaining emission 23

28 Specific GHG-emission [gco 2 -eq./mj] Calculated GHG emissions for cultivation () Hohenschulen, experimental year kg N 180 kg N(CAN) 180 kg NH4-N (BD) 180 kg NH4-N (BD+NI) direct N2O indirect N2O vol indirect N2O leach fertilizer production remaining emission 23

29 Specific GHG-emission [gco 2 -eq./mj] Calculated GHG emissions for cultivation () Hohenschulen, experimental year % GHG saving 0 kg N 180 kg N(CAN) 180 kg NH4-N (BD) 180 kg NH4-N (BD+NI) direct N2O indirect N2O vol indirect N2O leach fertilizer production remaining emission 23

30 Specific GHG-emission [gco 2 -eq./mj] Calculated GHG emissions for cultivation () Hohenschulen, experimental year % GHG saving Measured direct N 2 O emissions very low Ammonia emissions lower than calculated Organic fertilizer: No emissions from fertilizer production, but higher N input higher direct and indirect emissions 0 kg N 180 kg N(CAN) 180 kg NH4-N (BD) 180 kg NH4-N (BD+NI) direct N2O indirect N2O vol indirect N2O leach fertilizer production remaining emission 23

31 Summary Organic fertilizers with lower NUE Ammonia volatilization Ammonia emission 13% total N N 2 O: marginal differences between mineral and organic fertilizers on generally low level No advantages with nitrification inhibitor GHG emissions for biogas digestates: Higher than for mineral N fertilizer using EFs Lower than for mineral N fertilizer with emissions 50% GHG emission saving with calculated emissions not achievable 24

32 Thank you for your attention!

33 Acknowledgements