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 Risø DTU, Technical University of Denmark 2 Title of the presentation
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 314 0.15 296 Agriculture 1745 0.48 23 Global source strength ~16.4 TgN Landfills Carbon dioxide Fossil Estimated fuel sources 365000 1.46 1 (CO 2 ) Forests 6 TgN (3.3 9.7) Ag soils 4 TgN (0.6 14.8) * 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 1750. Temp. impact ~0.5 K/Wm -2 : Global warming potential on 100 yr time horizon 3 Risø DTU, Technical University of Denmark
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
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)
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
250 ton C/ha 100 ton C/ha The Black Earth 7 Risø DTU, Technical University of Denmark
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: www.carbon-negative.us Source: www.carbon-negative.us
Feedstock transformation Lehmann et al 2009. 9 Risø DTU, Technical University of Denmark
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.
Biochars stability depends on pyrolysis temperature and feedstock 365 days incubation 115 days incubation 30 loss har-c) Cumulative C l (% of initial bioch 20 10 0 475 C 500 C 525 C 550 C 575 C Biochar (wheat straw-based) Zimmerman 2010 Bruun et al. 2011 11 Risø DTU, Technical University of Denmark Photo: Greenpeace
Biochar increases soil water holding capacity 1 mixture (dw) 50 40 30 a) a 0 wt% 5 wt% 10 wt% ab b b c b bc ab b g -1 mixture (dw) 70 60 50 40 b) Control soil SP-biochar (525) FP-biochar (500) FP-biochar (525) Straw 12 Risø DTU, Technical University of Denmark
Biochar and N 2 O emissions? 13 Risø DTU, Technical University of Denmark Photo: Greenpeace
N 2 O from various bio-energy residues Cayuela et al., 2010 14 Risø DTU, Technical University of Denmark
N 2 O with different qualities of biochar C/N ratio C/N ratio 34 16 533 300 DNO3-N mg/kg 34 +65 16 +63 533 +46 300-5 +40 Van Zwieten et al., 2009 15 Risø DTU, Technical University of Denmark
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 -1 2-3 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 -1 86 days More than 50 % reduction 16 Risø DTU, Technical University of Denmark
FP-biochar effect on N 2 O soil emissions mg CO -1-1 soil mg CO 2 -C g 2 -C soil 0.0030 0.0025 0.0020 0.0015 0.0010 0.0005 CO CO 2 2 N 2 O 0.012 0.010 0.008 0.006 0.004 0.002 µg N -1 2 O-N g soil 0.0000 Bruun et al. 2011 Control Biochar Biochar Grass- soil soil 5 5 wt% wt% 10 10 wt% wt% Clover 0.000 Grass- Clover + + Biochar 10 10 wt% wt% (80% WFPS) 17 Risø DTU, Technical University of Denmark
Combine biochar with fertilizers to reduce N 2 O emission? 0.016 b) 1. Soil; ( control soil ) 2. + 1% biochar ; ( biochar-low ) 3. 0.012 + 3% biochar ; ( biochar-high ) 4. + slurry ; ( slurry ) 5. + slurry + 1% biochar ; ( blend-low ) 0.008 6. + slurry + 3 % biochar ; ( blend-high ) µg N 2 O-N g -1 soil h -1 High water content (80% WFPS) 0.004 80% WFPS, Slurry = anaerobically digested cattle slurry (low C, high N) 0.000 Control soil Biochar-L Biochar-H Slurry Blend-L Blend-H 1 wt% 3 wt% 1 wt% 3 wt% 0 2 4 6 8 10 50 60 Days 1.0 d) a Blend-L µg N 2 O-N g -1 soil 0.8 0.6 0.4 0.2 ab ab ab b c Blend-H 0.0 18 Risø DTU, Technical University of Denmark 0 10 20 30 40 50 60 Days Source: traktor-hostspecialisten.dk
What caused the reduced N 2 O with addition of biochar to slurry? µg DOC g -1 soil 200 150 100 a) Dissolved org C Control soil Biochar-L Biochar-H Slurry Blend-L Blend-H µg SMB-C g -1 soil 300 250 200 150 100 b) SMB C Control soil Biochar-L Biochar-H Slurry Blend-L Blend-H µg NO 3 - -N g -1 soil 100 80 60 40 a) Soil NO 3-50 50 20 0 0 10 20 30 40 50 60 Days 0 0 0 10 20 30 40 50 60 0 10 20 30 40 50 60 Days Bruun et al. 2011 Days 19 Risø DTU, Technical University of Denmark
Combined GHG (N 2 O+CO 2 ) emissions mg CO e 2 g-1 soil 1.4 ) b) 1.2 1.0 0.8 0.6 a 0.4 CO 2 N 2 O (CO 2 e) ab b bd c cd 0.2 0.0 Control soil Slurry Biochar-L Blend-L Biochar-H Blend-H Bruun et al. 2011 20 Risø DTU, Technical University of Denmark
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 0.4 0.2 0.0 0-10 -20-30 -40 b) Blend-H H mg CO2 e g-1 soil net mg CO2 e g-1 soil -50-60 Control soil Slurry Biochar-L Blend-L Biochar-H Blend-H biochar substantially reduced net GHG emissions (Rogovska et al., 2011) Bruun et al. 2011 21 Risø DTU, Technical University of Denmark
! 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
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
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25 Risø DTU, Technical University of Denmark