Biochar amendment to improve soil properties and sequester carbon Soil Science in a Changing World, Wageningen, Sept 18-22, 2011 Biochar amendment to improve soil properties and sequester carbon Lewis Peake PhD project School of Environmental Sciences University of East Anglia Norwich, UK Supervisor: Dr Brian Reid

What is biochar 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

Why is biochar important? 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

The apparent benefits of Biochar 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

The research question 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

The approach 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

Soil type selection Some research evidence of sand/ clay differing responses to biochar + texture is stable property Loamy sand: acid, low CEC excessively drained Sandy loam: neutral pH, medium CEC, freely drained Loam: neutral pH, med-high CEC, imperfectly drained Silty clay loam: calcareous, high CEC, estuarine, poorly drained Biochar amendment to improve soil properties and sequester carbon Lewis Peake

Biochar 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

Laboratory experiment 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

Results: Soil Moisture @ Field Capacity Biochar amendment to improve soil properties and sequester carbon Lewis Peake

Results: Bulk Density Biochar amendment to improve soil properties and sequester carbon Lewis Peake

Results: AWC by weight Biochar amendment to improve soil properties and sequester carbon Lewis Peake

Results: AWC by volume Biochar amendment to improve soil properties and sequester carbon Lewis Peake

Outdoor pot trial 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

Long-term farm 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

Biochar – a solution in a changing world? 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