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Lewis PeakeLewis PeakePhD project PhD project
School of Environmental SciencesSchool of Environmental Sciences
University of East AngliaUniversity of East Anglia
Norwich, UKNorwich, UK
Supervisor: Dr Brian ReidSupervisor: Dr Brian Reid
Soil Science in a Changing World, Wageningen, Sept 18-22, 2011
• Essentially a type of charcoal, but two distinctions:
– Created by thermal decomposition of biomass with little or no oxygen (pyrolysis or gasification)
– Intended as a soil amendment and a means of storing carbon
• Scientific study of biochar is about ten years old
• Terra preta de índio (Indian black earth)
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 2
What is biocharWhat is biochar
• Global soil reserves represent a large potential carbon sink BUT... traditional manures break down and oxidize rapidly
• Contains C in a form which is highly resistant to degradation
• Potential to sequester large amounts of C in the soil with a residence time of hundreds and possibly thousands of years
• Potential to be a C negative form of geo-engineering
• Research suggests that biochar use has many other soil benefits: chemical, physical and biological
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 3
Why is biochar important?Why is biochar important?
• Sequesters carbon in the soil
• Improves soil productivity, especially on poor soils
• Improves water retention / reduces water demand
• Improves water quality / less downstream pollution
• Reduces emissions of greenhouse gases from the soil
• Increases microbial activity
• Biofuel as a by-product and a renewable means of sustaining further biochar production
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 4
The apparent benefits of BiocharThe apparent benefits of Biochar
• If biochar is a viable means of boosting crop yields:
– What specific changes occur? – What rates of application are appropriate?
– Do different types of soil respond in different ways? – If, e.g. sand and clay soils respond in different ways, how would
a transitional soil type behave – a loam or a silt or a sandy clay?
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 5
The research questionThe research question
• To compare the physical and chemical responses to biochar of four contrasting agricultural soil types
• To use one type of biochar at a range of doses
• Laboratory experiment to test physical and hydrological effects, e.g. AWC
• 2-year outdoor pot trial to test mainly chemical effects
• 2-year farm trial to test range of effects
• Ultimate aim: strategic advice on biochar application
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 6
The approachThe approach
• Some research evidence of sand/ clay differing responses to biochar + texture is stable property
1. Loamy sand: acid, low CEC excessively drained
2. Sandy loam: neutral pH, medium CEC, freely drained
3. Loam: neutral pH, med-high CEC, imperfectly drained
4. Silty clay loam: calcareous, high CEC, estuarine,
poorly drained
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 7
Soil type selectionSoil type selection
• Ready supply on our “doorstep”:– UEA Combined Heat & Power biomass plant– Uniform feedstock of softwood sawmill waste – Gasification at 800 o C– Output 300 t/yr biochar
• Project limited to one type of biochar– Feedstock & production temperature important BUT...– Different types of biochar beyond scope– Project includes n soils / doses / replicates– Impossible to study multiple biochars as well
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 8
Biochar selectionBiochar selection
• Physical & hydrological testing with winter wheat
• Tested 5 soils for:
– Field Capacity– Bulk Density– Available Water Capacity
• Biochar doses: 0/0.1/0.5/2.5 % (≈ 0/4/20/100 t ha-1)
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 9
Laboratory experimentLaboratory experiment
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 10
Results: Soil Moisture @ Field CapacityResults: Soil Moisture @ Field Capacity
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 11
Results: Bulk DensityResults: Bulk Density
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 12
Results: AWC by weightResults: AWC by weight
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 13
Results: AWC by volumeResults: AWC by volume
• Mainly chemical testing with winter wheat
• Quarterly sampling over two years
• Biochar doses: 0/0.1/0.5/2.5 % (≈ 0/4/20/100 t ha-1)
• 4 soils x 4 treatments x 4 replicates = 64 pots
• Comprehensive analysis: cations, anions, pH, CEC
• Collaborating with U/G project on one soil type:– Includes fertilized treatments
– Analyses includes CO2 emissions
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 14
Outdoor pot trialOutdoor pot trial
• Local farm estate which includes the 4 core soils
• 3 of these soils are naturally low in organic matter:– Aggravates drought risk which climate change has increased– Structural problems– Erosion risk– Buyers discouraging use of organic manures
• Scaled-up version of lab and pot trials:– 3 soils to receive single dose; one to have 4 doses– Emphasis will be on physical & hydrological properties– Soil moisture release curves using Tempe cell cores
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 15
Long-term farm trialLong-term farm trial
• Global Food Security:– Increased yields; Reduced erosion risk
• Water Resources:– Enhanced water retention; Improved water quality
• Biodiversity:– Enhanced microbial activity; Reduced downstream pollution
• Governance & Policy:– Strategic geo-engineering; C credits opportunity
• Climate Change:– Carbon sequestered; N2O & CH4 emissions suppressed;
– Part of a sustainable biomass/biofuel system
Biochar amendment to improve soil properties and sequester carbon Lewis Peake 16
Biochar – a solution in a changing world?Biochar – a solution in a changing world?