Application of biochar as a tool to mitigate non-co2 greenhouse gas emissions from soil

Transcription

1 Application of biochar as a tool to mitigate non-co2 greenhouse gas emissions from soil Per Ambus Risø National Laboratory for Sustainable Energy Technical University of Denmark Biochar sequesters carbon Biochar reduces soil GHG Biochar improves soil quality Biochar increases crop yields..

2 2 Risø DTU, Technical University of Denmark 2 Title of the presentation

3 Properties of dominant greenhouse gases Nitrous oxide (N 2 O) Methane (CH 4 ) Source [Atm.] (ppb) Radiative forcing (Wm -2 )* GWP Agriculture Combustion Atmospheric burden ~1510 TgN Agriculture Global source strength ~16.4 TgN Landfills Carbon dioxide Fossil Estimated fuel sources (CO 2 ) Forests 6 TgN ( ) Ag soils 4 TgN ( ) * The change in "Net Ocean irradiance, 3 Tg N(1-5) i.e. the difference between the incoming radiation Other energy 3 TgN and the outgoing radiation energy in a given climate system. Due to conc since yr Temp. impact ~0.5 K/Wm -2 : Global warming potential on 100 yr time horizon 3 Risø DTU, Technical University of Denmark

4 N 2 O production pathways in soils NH 4 + Ammonium Nitrification NH 2 OH Hydroxylamine NO 2 - Nitrite NO Nitric oxide N 2 O Nitrous oxide N 2 O Nitrous oxide NO 3 - Nitrate NO 2 - Nitrite NO Nitric oxide Dissimilatory Nitrate Reduction to Ammonium NO - 2 N 2 O NH + 4 Nitrite Nitrous oxide Ammonium N 2 O Nitrous oxide Chemical nitrite reduction N 2 Di-Nitrogen N 2 O Nitrous oxide Wrage et al., 2001 Nitrifier denitrification N 2 Di-nitrogen 4 Risø DTU, Technical University of Denmark Denitrification

5 Control of biogenic N 2 O production Nitrogen availability Fertiliser, Atmosphere, Soil quality Organic carbon availability Residue management, crop rotations, soil quality Oxygen availability Irrigation, precipitation, soil texture, soil WHC Physio-chemical environment Temperatur, ph NO N 2 O NO N 2 O NH 4 + NO 3 - Nitrification 5 Risø DTU, Technical University of Denmark Denitrification N 2 (Davidson & Firestone, 1989)

6 Biochar sequesters carbon Biochar interacts with soil nitrogen availability Returns nutrients to the field (ash part) Biochar increases ph in acidic soils due to BC s content of bases (Ca, Mg, K etc.). Short term liming effect. Forms aggregates with the soil particles and stabilizes the soil Increases the cation exhange capacity (CEC) of the soil Increase soil microbial biomass Increases water holding capacity Increases soil porosity and aeration 6 Risø DTU, Technical University of Denmark

7 250 ton C/ha 100 ton C/ha The Black Earth 7 Risø DTU, Technical University of Denmark

8 Source:http: cmc-indo.blogspot.com Biochar is not just biochar Source: earthportal.org Source: CarbonGold Source: infosdelaplanete.org 8 Risø DTU, Technical University of Denmark Source: Source:

9 Feedstock transformation Lehmann et al Risø DTU, Technical University of Denmark

10 Biochar microstructure a) Wheat straw c) SP-biochar e) FP-biochar (525 C) (525 C) 500 µm 500 µm 500 µm b) Wheat straw d) SP-biochar f) FP-biochar Beech wood 20 µm 20 µm 20 µm 10 Risø DTU, Technical University of Denmark Bruun et al. 2011b.

11 Biochars stability depends on pyrolysis temperature and feedstock 365 days incubation 115 days incubation 30 loss har-c) Cumulative C l (% of initial bioch C 500 C 525 C 550 C 575 C Biochar (wheat straw-based) Zimmerman 2010 Bruun et al Risø DTU, Technical University of Denmark Photo: Greenpeace

12 Biochar increases soil water holding capacity 1 mixture (dw) a) a 0 wt% 5 wt% 10 wt% ab b b c b bc ab b g -1 mixture (dw) b) Control soil SP-biochar (525) FP-biochar (500) FP-biochar (525) Straw 12 Risø DTU, Technical University of Denmark

13 Biochar and N 2 O emissions? 13 Risø DTU, Technical University of Denmark Photo: Greenpeace

14 N 2 O from various bio-energy residues Cayuela et al., Risø DTU, Technical University of Denmark

15 N 2 O with different qualities of biochar C/N ratio C/N ratio DNO3-N mg/kg Van Zwieten et al., Risø DTU, Technical University of Denmark

16 Biochar effects on N 2 O emissions Study Biochar added (% of soil DM) Duration Summary response Yanai et al. (2007) 8 10 % Short-term Up to 89% reduction Spokas et al. (2009) 20, 40 and 60 % 100 days Up to 74% reduction 2, 5 and 10 % 100 days No reduction = Cayuela et al. (2010) 50 mg/kg N 60 days Below background Clough et al. (2010) 4 % 53 days No reduction = Singh et al. (2010) 0.8 % Start of the exp. No reduction = Up to 73% reduction After two subsequent rewetting cycles (5 month) 120 days 21 to 58% reduction -/+ Zhang et al. (2010) 0, 10 and 40 t ha -1 N-fertilization Bruun et al. (2011) 0, 1 and 3% 55 days 47% reduction to 7X increase +/- slurry Clemens et al. (2011) 10 t ha month No reduction = Rogovska et al. (2011) 0, 0,5, 1 and 2% 414 days Up to 88% reduction +/- manure Taghizadeh-Toosi et al. (2011) 30 t ha days More than 50 % reduction 16 Risø DTU, Technical University of Denmark

17 FP-biochar effect on N 2 O soil emissions mg CO -1-1 soil mg CO 2 -C g 2 -C soil CO CO 2 2 N 2 O µg N -1 2 O-N g soil Bruun et al Control Biochar Biochar Grass- soil soil 5 5 wt% wt% wt% wt% Clover Grass- Clover + + Biochar wt% wt% (80% WFPS) 17 Risø DTU, Technical University of Denmark

18 Combine biochar with fertilizers to reduce N 2 O emission? b) 1. Soil; ( control soil ) % biochar ; ( biochar-low ) % biochar ; ( biochar-high ) 4. + slurry ; ( slurry ) 5. + slurry + 1% biochar ; ( blend-low ) slurry + 3 % biochar ; ( blend-high ) µg N 2 O-N g -1 soil h -1 High water content (80% WFPS) % WFPS, Slurry = anaerobically digested cattle slurry (low C, high N) Control soil Biochar-L Biochar-H Slurry Blend-L Blend-H 1 wt% 3 wt% 1 wt% 3 wt% Days 1.0 d) a Blend-L µg N 2 O-N g -1 soil ab ab ab b c Blend-H Risø DTU, Technical University of Denmark Days Source: traktor-hostspecialisten.dk

19 What caused the reduced N 2 O with addition of biochar to slurry? µg DOC g -1 soil a) Dissolved org C Control soil Biochar-L Biochar-H Slurry Blend-L Blend-H µg SMB-C g -1 soil b) SMB C Control soil Biochar-L Biochar-H Slurry Blend-L Blend-H µg NO 3 - -N g -1 soil a) Soil NO Days Days Bruun et al Days 19 Risø DTU, Technical University of Denmark

20 Combined GHG (N 2 O+CO 2 ) emissions mg CO e 2 g-1 soil 1.4 ) b) a 0.4 CO 2 N 2 O (CO 2 e) ab b bd c cd Control soil Slurry Biochar-L Blend-L Biochar-H Blend-H Bruun et al Risø DTU, Technical University of Denmark

21 Significant net GHG reduction with slurry + biochar c 1.4 b) cd 1.2 bd 1.0 b 0.8 ab 0.6 a Control soil Slurry y Biochar-L Blend-L L Biochar-H H b) Blend-H H mg CO2 e g-1 soil net mg CO2 e g-1 soil Control soil Slurry Biochar-L Blend-L Biochar-H Blend-H biochar substantially reduced net GHG emissions (Rogovska et al., 2011) Bruun et al Risø DTU, Technical University of Denmark

22 ! Biochar can induce soil N 2O emissions Application of C-rich biochar with organic fertilizer may decrease soil N 2 O emissions Results are ambiguous, and more research is needed to characterize mechanisms Biochar is not just biochar! Biochar short-term stability and properties in soil is strongly affected by pyrolysis technology and settings, which also affects influence on N 2 O. Considering also the C-sequestration potentials, biochar has strong reducing effect on net GHG emissions from agricultural soils. 22 Risø DTU, Technical University of Denmark

23 Contributors PhD Esben Wilson Bruun Dr Dorette Müller-Stöver Dr Henrik Hauggaard-Nielsen Tech staff Nina Wiese Thomsen Anja Nielsen 23 Risø DTU, Technical University of Denmark

24 Thanks for your attention!

25 25 Risø DTU, Technical University of Denmark