Lewis Peake PhD project School of Environmental Sciences University of East Anglia Norwich, UK Supervisor: Dr Brian Reid Soil Science in a Changing World,

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)

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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

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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

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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?

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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

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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

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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

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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)

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Laboratory experimentLaboratory experiment

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Results: Soil Moisture @ Field CapacityResults: Soil Moisture @ Field Capacity

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Results: Bulk DensityResults: Bulk Density

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Results: AWC by weightResults: AWC by weight

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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

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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

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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

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Biochar – a solution in a changing world?Biochar – a solution in a changing world?