OPTIONS FOR ABATEMENT
Purpose: To provide participants with an understanding of
the range of options available to land managers to
increase carbon storage and reduce emissions from
agricultural systems.
Source: University of Melbourne (UoM) June 2013
Indicative Abatement from CFI
Australia’s Annual Emissions
565 Mt CO2-e yr-1
DCCEE 2011
Indicative Abatement from CFI
Non-Forest sinks
• Options for increasing and managing
• Soil carbon
• Biochar
Soil carbon
Many AUS soils have low soil C levels
 old and weathered nature. Warm and dry climate
Large losses of soil C since conversion of native vegetation to
agriculture
AUS farmers have adopted practices that reduce soil disturbance
 Adoption of no-till and conservation farming practices
 Adoption levels 90% in some areas
 Rapid increases in last 5-10 years
Soil carbon loss can be reduced or soil carbon increased by:
 Promotion of more plant growth
 Adding organic matter from offsite sources
Garnaut Climate Change review update 2011
Soil carbon
Potential to increase soil carbon at any location depends:
 Soil type
 Water and nutrient availability
 Temperature
 Management history
Mitigation options with potential but little data:
 Addition of large amounts of organic materials
 Maximising pasture phases in mixed cropping systems
 Shift from annual to perennial species
Considerable uncertainties for all of these opportunities
Few studies have tracked effects of management changes on soil
carbon over an extended period
Risks – drought can reverse potential increases in soil carbon
Garnaut Climate Change review update 2011, Chapter 4
Can we quantify changes in soil carbon?
• Will not be able measure in short-term
• Will need to couple
Soil organic carbon
(Mg C/ha)
– Modelling and
– Measured points in time as means of
validation
60
50
40
30
20
10
0
0
5
10
15
Time (years)
20
Source: Jeff Baldock
Final Thoughts
• Building soil carbon is good practice
• Trading soil C is a separate discussion
– Non-Kyoto offsets may be lower priced
– Rate of change in Soil C is slow (decades)
– Reaches a saturation point, not
permanently increasing
– Rainfall and management are significant
determinant of input vs losses of soil
carbon
Biochar
Lehmann (2007) Front Ecol Env 5: 381
Biochar
Biochar can be produced from biological sources
 wood, agricultural crop residues, green waste,
biosolids
Gas produced in the biochar production process:
 Production of electricity, conversion to liquid fuels
Biochar has a greater stability than the material from which it is made
 Potential long-term carbon store
Biochar can improve soil fertility
 Potential biosequestration benefits through enhanced plant growth
Garnaut Climate Change review update 2011, Chapter 4
Biochar
Mitigation potential of biochar depends on life-cycle emissions from:
 production of biochar feedstock and changes in land-use
 production, transport and storage of biochar
 displacement of fossil fuel emissions
Economic viability of biochar production and application
 cost of feedstock and pyrolysis
 impact on crop yield and fertiliser requirements
 returns from renewable energy and a carbon price
Garnaut Climate Change review update 2011, Chapter 4
Biochar – life cycle analysis
Different models
to calculate
production
emissions
Waste biomass streams have greatest potential
Energy crops can be GHG positive, emit more GHG than they sequester
Agric residues have potential for GHG reductions, moderate potential to be profitable
Assumption: 80% of biochar is stable in soil! Roberts et al (2010) Env Sci Tech 44: 827
Biochar
Mallee species
Integrated tree processing:
 Produce eucalyptus oil, bioenergy & biochar
 only profitable if bioenergy production is
close to plantation
 due to high production cost (harvesting &
transport) & low product price for wood energy
In US:
Bioenergy & biochar production economically
attractive at emissions permit price >US$37
Polglase et al (2008)
Biochar
Biochar is a promising theoretical concept
 multiple environmental benefits
 reduced fossil fuel emissions
 C storage in soil
 potentially improved soil fertility
HOWEVER
• Most of the theoretical benefits need validation in the field
• Beware of perverse outcomes (sustainability issues)
• Economy of scale need to be tested
• Industry needs to develop
Forest sinks
Management of afforestation and reforestation for
generating offset credits
Managed existing forests
Conservation forests
Native forests cover 147 M ha of land in AUS = 20% of land mass
• 23 M ha in conservation reserves
• 9.4 M ha in public land timber production permitted
• Rest public land other purposes and private land
Forests (pre 1990)
136 Mt CO2-e yr-1 for 100 yrs, assumes C stocks at 40%
capacity, timber harvesting ceases in 14 M ha
CSIRO: if native forest harvesting is to cease = 47M t CO2 eq yr
Risks:
• Fire, Diseases
• Forests close to “carbon carrying capacity”
Managed existing forests
Total carbon in total tree biomass (above-ground plus roots) of Sequestration and emissions
native forests, 2000 to 2004, by forest vegetation group
in forests in 2005
Native forests stored 24.1 billion t of CO2 in biomass in 2004
 46 yr of total AUS emissions
Almost no change (a decrease of 0.7%) between 1989 and 2004 in
native forest total tree woody biomass
 some increases: woody thickening, increased extent (fire freq)
 some decreases: broadscale clearing, firewood, mortality (fire)
Only 0.06% of C stored in native forests was harvested (3.8 M t CO2)
~43.5 M t CO2 new growth in 2005
~31.9 M t CO2 of net sequestration
State of Forests Report (2008)
Non forest re-vegetation
Rangeland rehabilitation in Arid Australia
Vast areas of wooded land – red centre
Arid and semi arid rangelands
70% of AUS land mass - 550 M ha
 Restoration of rangelands by reducing grazing pressure
or palatable shrubs like saltbush, tagasaste, perennial
shrubs
286 Mt CO2-e yr-1 20-50 yrs
(improve degraded rangeland all grazing land
358 M ha = 0.2 t C ha-1yr-1)
CFI methodology for rangeland rehabilitation is being
developed at present
Non forest re-vegetation - biofuels
Biofuels
First generation biofuels = 1% of global transport fuel consumption
(sugarcane, corn, sugar beets, potatoes…)
To satisfy global demand = 75% of worlds agricultural land
Second generation biofuels:
 Waste biomass, lignocellulosic material, algae, Pongamia, Jatropha
Opportunity for Mallee species (coppiced)
Research needed to identify best cropping systems for AUS
Reforestation and afforestation
Plantation and production forests
Doubling the plantation estate could increase C sequestration in plantations
In AUS to 50 Mt CO2 by 2020
C storage by forest ecosystems:
1. Storage of C in forest biomass and soil
2. Storage of C in forest products – paper, furniture, construction
3. Displacement – use of biofuels to replace fossil fuels
4. Substitution – use of wood products that replace fossil fuel intensive
products (concrete, steel, aluminium, plastic)
Reforestation and afforestation
Carbon storage in forests and wood products, Australia
Large amounts of
carbon are stored in
wood products that are
in service and in landfill
Emission and storage of carbon in the
manufacture of building materials (kg/m3)
Concrete, steel and aluminium
have large emissions during
production processes
 Large substitution benefits
State of Forests Report (2008)
Reforestation and afforestation
Environmental carbon plantings
Revegetation of cleared or degraded land
Potentially available land = 200 M ha
• climatic suitability
• soil suitability
• species characteristics
• profitability compared to current land-use
• rainfall interception
Reforestation and afforestation
Environmental carbon plantings
Total carbon in live biomass for 20 y.o. environmental
plantings (t CO2-e ha-1yr-1) normalised for 20 yrs
Polglase et al. (2008)
Reforestation and afforestation
Carbon forest plantings
CSIRO (2009): at a C price of $20/t CO2 & incentives
for biodiversity benefits = 350 M t CO2 yr-1
•
•
•
•
•
Mixed native species
Mallees
Other benefits for biodiversity, NRM or farm productivity
Planted in blocks, widely spaced rows, along stream banks
Corridor for native species
At least 20 businesses & non for profit organisations are offering carbon
forest offsets in Australia:
Greening Australia, Greenfleet, Landcare Carbon Smart, CO2 Australia…
http://www.carbonoffsetguide.com.au/
 Opportunities in a wider range of climate zones
 In areas where agric. production is marginal and plantations fail
 Diversification of income for farmers
Reforestation and afforestation
Agroforestry
Farming practices and forestry options
Integration of trees and shrubs into farming landscapes for
conservation and profit
Using trees to improve the environmental, social and economic values
of their land
Greenhouse Gas Sources
• Options for reducing methane and nitrous oxide emissions
• Already registered as CFI offset methods
• In research towards imminent development as a CFI
method
• Longer term research to develop options for the future
Options for abatement – Methane – CFI methods
• Methane from
–
–
–
–
Piggeries biodigesters
Piggery manure
Dairy anaerobic ponds
Dairy cows through feeding high-oil by-products
• Savanna burning
• Methane from landfill
–
–
–
–
Avoided emissions to fuel manufacture
Avoided emissions through composting
Capture and combustion of landfill gas
Diverting waste to an alternative waste treatment facility
Full details on these methodologies can be found at:
www.climatechange.gov.au/government/initiatives/carbon-farminginitiative/methodology-development/determinations.aspx
Options for abatement – Enteric Methane
Technologies to Reduce
Enteric Methane Emissions
Animal
Manipulation
Diet
Manipulation
Rumen
Manipulation
Forage
quality
Animal
Breeding
Residual Feed
Intake
Biological
Control
Plant
Breeding
Bacteriophages
bacteriocins
Efficiency
Reductive
Acetogenesis
Dietary
Supplements
Management
Systems
Dietary Oils
Alternative
livestock systems
Vaccination
Probiotics
Unproductive
Animals
Enzymes
Chemical
Defaunation
Dicarboxylic
acids
Plant Secondary
Compounds
Tannin &
Saponin
Eckard 2008
Options for abatement – Nitrous Oxide
Technologies to reduce
Nitrous Oxide emissions
Animal
Soils
Physical
interventions
Restricted
Grazing
Feed Conversion
Efficiency
Breeding
Plant breeding
eg. tannins
Dietary
Interventions
Chemical
Intgerventions
Balancing
Protein: Energy
Salt
Nitrification
inhibitor in urine
Fertiliser
Rate
Waterlogging /
drainage
Source
Irrigation
Timing
Compaction
Effluent
Management
Controlled
Release
Nitrification
Inhibitors
Eckard 2008
Options for abatement – Enteric Methane
Mitigation %
“Silver bullet”
45
40
35
30
25
20
15
10
5
0
Biological control
Vaccination
Dietary
Supplements
Rumen manipulation
Breeding
BMPs
Herd Management
Low
Immediate
High
Medium
Likely
Impact
High
Timeline
Longer Term
Confidence
Low
Eckard, Grainger & de Klein 2010
Options for abatement – Nitrous oxide
“Silver bullet”
25
Biological control
Animal
Breeding
Mitigation %
20
15
Nitrification
Inhibitors
10
BMPs
5
Diet
Plant
Breeding
Soil Microbial
Manipulation
Secondary plant
compounds
Herd Management
0
Low
Immediate
High
Likely
Impact
Medium
High
Timeline
Longer Term
Confidence
Low
De Klein & Eckard 2008
Options for abatement – Methane – Short Term
• Feeding
– Feed quality
• Pasture improvement
• C3 pastures, legumes
– Dietary supplements
• Grain
• Tannins
• Oils
– 1% fat = 3.5% decrease CH4 /kg DMI
– Out for public consultation for dairy cows
Eckard et al. 2010; Moate et al. 2010
Options for abatement – Methane – Short Term
• Improving efficiency
– Improved feed conversion efficiency
– Cross-breeding/ hybrid vigour
– Earlier mating and earlier finishing
– Improved fertility and weaning rates
– Improved health
Eckard et al. 2010
Options for abatement - Methane
• Longer Term Research
– Animal Breeding
• Feed conversion efficiency
• Reduced methanogenesis
– Plant Breeding
• Improved energy to protein ratio
• Tannin, oils, sugars
Eckard, Grainger & de Klein 2010
Options for abatement - Methane
• Longer Term research
– Rumen manipulation/ biological control
• Vaccination
• Competitive or predatory microbes
• Microbial inhibitors
Eckard, Grainger & de Klein 2010
Options for abatement – nitrous oxide
• Nitrogen Fertiliser Rate
• Match to plant demand
• Similar with effluent
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Environment
11.7
8.1
30
Annual N2O emission (kg N/ha.y)
P redicted P asture G row th (t D M /ha.y)
Productivity
13.3
6.0
8.5
11.2
U rea
N itrate
Urea
Nitrate
25
20
15
10
5
0
0
100
200
300
400
500
600
A nnual N F ertiliser R ate (kg N /ha.y)
700
800
900
0
100
200
300
400
500
600
Nitrogen Fertiliser Rate (kg N/ha.y)
Eckard et al. 2006
Options for abatement – Nitrous oxide
• Nitrogen Fertiliser Rate
Nitrous oxide-N (kg/ha)
10
Cotton
8
Wheat-VetchCotton
Wheat-Cotton
6
4
2
0
0
100
N rate
200
300
Grace et al. 2007
Options for abatement – Nitrous oxide
• Nitrogen Fertiliser Source
• In wet soils
– N2O (nitrous oxide) from NO3-N (nitrate) source
– Denitrification or leaching
• In dry soils
• Nitrogen Placement
• Band, ridges
• Within paddock
Annual N2O emission (kg N/ha.y)
– N2O (nitrous oxide) from NH3 (ammonia)
30
– Volatilisation from urea
Urea
25
Nitrate
20
15
10
5
0
0
100
200
300
400
500
600
Nitrogen Fertiliser Rate (kg N/ha.y)
Eckard et al. 2006
Options for abatement – Nitrous oxide
• Nitrogen Source and Timing
1.8
Control
Ammonium nitrate
Urea
1.6
1.4
Nitrous Oxide loss (kg N/ha)
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Autumn
Winter
Spring
Summer
Eckard et al. 2002
Options for abatement – Nitrous oxide
• Fertiliser Formulation
– Urease inhibitors
• Reduces NH3 (ammonia) volatilisation
– eg. Agrotain®, Green UreaTM
– Nitrification inhibitors
• Reduces N2O (nitrous oxide) and
NO3 (nitrate) leaching
• Temperature sensitive
ENTEC®
– eg. DCD, Nitrapyrin, DMPP
De Klein & Eckard 2008
Options for abatement – Nitrous oxide
• Fertiliser Formulation
– Nitrification Inhibitor sprays on pasture
• 50% less N2O
– for 50 days mid-spring
• 25% less N2O
– for 25 days in summer
Kelly et al;. 2008
Options for abatement – Nitrous oxide
• Fertiliser Formulation
– Controlled Release/Coated Fertilisers
• Polymer or oil-based coating
– Controlled pattern/rate of release
– Slow Release Fertilisers
• Reduced solubility
– Chemical
– Physical mixing
• Slower release of N
De Klein & Eckard 2008
Options for abatement – Nitrous oxide
• Soil Water / irrigation management
Granli and Bøckman (1994)
Options for abatement – Nitrous oxide
• Soil Management
– Limited grazing on wet soils/ use of feedpads
– Soil structure
• Reduce waterlogging with N
• Reduce soil compaction with N
– Stubble management
• Retain stubble
• Conservation tillage and controlled traffic
• Build soil organic matter
– Reduce fallow
• Loss of unutilised N
• Cover crops
De Klein & Eckard 2008
Options for abatement – Nitrous oxide
• Longer term
– Plant breeding
• Tannin content
• Less N required
– Animal breeding
• More N efficient
– Microbial manipulation
• Soil
• Animal rumen
De Klein & Eckard 2008
Options for abatement – N2O
• Urine Management
• Ruminants excrete 75 to 95% of N intake
• Immediate
– Balancing ME:CP
– Feed tannins
– Animal numbers
• Reduce hot-spots
– Inhibitors
• Inhibitor spray
• Longer Term
Research
– Breeding
• Improve animal FCE
• Improve plant
– ME:CP
– tannins
Grainger et al. 2009; De Klein & Eckard 2008
© Copyright 2013 The University of Melbourne, The Carbon Market Institute and the Department of Agriculture, Fisheries and Forestry, Carbon Farming Futures, Extension and Outreach
Program