The Case for Biochar. Annette Cowie, Bhupinderpal Singh Lukas Van Zwieten

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1 The Case for Biochar Annette Cowie, Bhupinderpal Singh Lukas Van Zwieten

2 Amazonian Terra preta Terra preta (dark earth) soils High plant productivity High organic carbon stable char (black carbon) Source:

3 Recreate Terra preta? Pyrolysed biomass as a soil amendment Source: Adriana Downie Pacific Pyrolysis

5 Dynamotive - fast-pyrolysis Splainex Waste Pyrolysis Pacific Pyrolysis EEA Continuous Flow System - scrap tyres Adriana Downie June 2012

6 Recalcitrant National Biochar Initiative: E Krull CSIRO

7 Source: L. Van Zwieten

8 Recalcitrant Source: S. Joseph UNSW Source: E Krull CSIRO

carbon CO 2 - Mineralisation Labile carbon: Microbial biomass, Biomass C

9 Terrestrial Carbon Cycle Atmosphere Photosynthesis Respiration Substrate C litter Particulate & roots carbon Assimilation Death Humified Organic carbon carbon CO 2 - Mineralisation Labile carbon: Microbial biomass, Biomass C Soluble C Humification Fire Charcoal Charcoal After J. Skjemstad, CRC Greenhouse Accounting

10 Cumulative per cent of biochar-c decomposed BP Singh et al (EST) 10.0 Low-temperature (400 o C) biochars High-temperature (550 o C) biochars Poultry litter Papermill sludge 8.0 Cumulative % of added biochar-c mineralized Cow manure Eucalyptus leaf Eucalyptus wood Poultry litter Cow manure Eucalyptus leaf Cumulative % of added biochar-c mineralized 0.0 Eucalyptus wood Duration of incubation (days) 0.5% to 8.9% of biochar C mineralized over 5 years.

11 Biochar stability - a function of feedstock and pyrolysis conditions BP Singh et al (EST) Pyrolysis temperature Most stable (~2000 years) Carbon content 550 C leaf (A) 550 C poultry (A) 550 C cow (A) 400 C wood (A or NA) 400 C leaf (A) 550 C paper sludge (A)?? 400 C manures (poultry, cow) (NA) 550 C wood (A or NA) Fused aromatic rings Least stable (~100 years) Mineral nutrient content Synthesis: after E. Krull

12 Biochar can reduce soil N 2 O emissions Alfisol Control Vertisol Cumulative N2O emissions µg /m Poultry manure_400 Wood_550 Poultry manure_550 Wood_ % reduction in N2O 23-52% reduction in N2O 4-Aug 9-Aug 14-Aug 19-Aug 24-Aug 29-Aug 4-Aug 9-Aug 14-Aug 19-Aug 24-Aug 29-Aug 0 The day of gas sampling The day of gas sampling BP Singh et al (JEQ)

13 Nitrous oxide measurement

14 N 2 O (kg.ha 1.hr 1 ) N 2 O emissions Poultry Biochar+Urea Urea N 2 O-N (kg.ha -1 ) Calculated Emission Factor Biochar+ Urea Urea Poultry litter standard error = 1.0 least significant difference (5% critical value) = Rain (mm) Temp C 09 Dec 23 Dec 06 Jan 20 Jan 03 Feb Van Zwieten et al (2013) Science of the Total Environment.

15 Biochar impact on soil porosity National Biochar Initiative: Peter Quin et al UNE/NSW DPI

16 Cumulative priming of soil C by biochar 400 C biochars 550 C biochars Singh & Cowie (Unpublished) (c) (d) Cumulative primed soil CO2-C (mg g -1 soil C) Wood400 Leaf400A PL400 CM400 YWood450_2%LOM YWood450_4%LOM Wood550 Leaf550A PL550A CM550A YWood450_2%LOM YWood550_4%LOM Cumulative primed soil CO2-C (mg g -1 soil C) Duration of incubation (days) Biochar initially enhanced mineralisation of native soil C Native soil C was stabilised as biochar aged

17 GHG mitigation benefits of biochar Delayed decomposition of biomass Reduced nitrous oxide emissions from soil Increased soil organic matter Avoided fossil fuel emissions due to use of syngas as renewable energy Increased plant growth, plant health Avoided emissions from N fertiliser manufacture Reduced fuel use in cultivation, irrigation Avoided methane and nitrous oxide emissions due to avoided decay of residues

18 Biochar system Reference system Biomass residue Biomass residue Fossil energy/carbon source Transport Extraction Pyrolysis to biochar and syngas Transport Composting Transport Conversion to energy carrier Distribution of biochar Distribution of energy carrier Distribution of compost Distribution of energy carrier Fertiliser manufacture Distribution of fertiliser Soil amendment Energy service (heat, electricity) Soil amendment Energy service (heat, electricity)

19 Life cycle GHG emissions Maize Wheat

20 Poultry litter biochar applied to broccoli Factors contributing to mitigation Greenwaste biochar applied to canola

21 Potential mitigation through biochar - global Woolf et al 2010 Total mitigation predicted: 6 Gt CO 2 -e pa =12% current emissions

22 Interactions between herbicide and biochar National Biochar Initiative, Rai Kookana CSIRO

23 Contamination risk? National Biochar Initiative, Mark Farrell, CSIRO

24 Sustainability issues for biochar direct (1) Biomass procurement Residues: Soil erosion Soil compaction Nutrient depletion Soil carbon loss (GHG, productivity impact) Purpose grown: Water use Biomass and/or soil carbon decline GHG balance - N 2 O emissions

Sustainability issues for biochar direct (2)

Whole system: net mitigation benefit (incl

27 Sustainability issues for biochar direct (2) Biochar production GHG emissions particulate emissions Biochar application dust contamination (if feedstock contaminated) Whole system: net mitigation benefit (incl transport, plant construction) Compared with reference use

28 Sustainability issues for biochar indirect Indirect land use change Deforestation GHG emissions: loss of biomass carbon, soil carbon Biodiversity Air pollution Water quality Social community displacement, food security Economic competing uses of biomass

29 How can we encourage sustainability? Sustainability framework approach: Institutional systems: Regulation Incentives Standards Guidelines Certification Monitoring, assessment and reporting Criteria and Indicators Adaptive management

30 What do we know about biochar? Biochar can increase plant yield But not all plants / all soils Biochar is resistant to decomposition But some biochars are more resistant than others Biochar can reduce nitrous oxide emissions But not from nitrification Biochar can deliver net greenhouse gas mitigation Other options may give greater mitigation; each situation must be assessed separately Biochar could contaminate soil But only if made from contaminated feedstock Some unintended consequences Biochar can reduce efficacy of herbicides

31 Biochar can Contribute significantly to climate change mitigation Enhance agricultural productivity Restore degraded soils BUT ONLY IF produced in a facility that controls emissions and harnesses heat for efficient beneficial use applied with care, to responsive soil type / crop made from sustainably harvested and renewable biomass resources

32 More information: International Biochar Initiative

Biochar: Can it reduce pressure on the land? Annette Cowie National Centre for Rural Greenhouse Gas Research

Biochar: Can it reduce pressure on the land? Annette Cowie National Centre for Rural Greenhouse Gas Research What is biochar? Amazonian Terra preta Terra preta (dark earth) soils High plant productivity