BIOCHAR FOR SOIL FERTILITY AND CARBON SEQUESTRATION

Dr S. Joseph

The Carbon Equation

Source; Amonette J (US Dept of Energy), Joseph S, Lehmann J; Biomass carbonization: The dark side of terrestrial carbon sequestration. NSCE meeting 2007

What is Biochar ?

Biochar is the Solid Product Derived Thermal Decomposition of Biomass , Peat and Lignite for Use (Mainly) in Agriculture and Soil Decontamination.

Both Wood and Many Sources of Rural and Urban Wastes Can be Converted into Biochar.

Forest and Field Fires Produce Biochar. This Biochar is Important to Regenerate and Maintain the Health of the Forests and the fields.

Charcoal Is also Derived From The Thermal Decomposition Of Biomass but it is Further Used as a Source Of Energy.

Processing of Biochar Takes Place in an Environment where All or Most of the Oxygen is Excluded. Char, a Hydrogen Rich Gas, and a Bio-oil are Produced. The Gas and Oil Can be Used to Produce Energy or as a liquid Fuel.

This Process is Known as Pyrolysis.

UNIQUE PROPERTIES OF BIOCHAR

Source and AcknowledgementDiscussion paper for an Agricultural Research Western Australia workshop on potential benefits of Biochar; 20th June 2007, University of Western Australia. Dr Paul Blackwell, W.A. Dept of Agriculture, June 2007Lukas Van Zweiten; Putting carbon back in soil through the generation of renewable energy; DPI 2006

Biochar has a carbon content (on an ash free basis) of greater than 80%. It is usually dry and can be compressed Very Stable Resulting in Long-term Increases in Soil Organic CarbonC Sequestration and Greenhouse BenefitsImproving Soil Physical Chemistry by

1) increasing cation exchange capacity of soils with low clay content,

2) reducing acidity and exchangeable aluminium, 3) potentially increasing water-holding capacity.

Facilitating Growth of Beneficial Soil Microbiology to Enhance Supply Of Water, N,P,K and Other Nutrients into Plant Roots, Improved Crop Yields and Can Enhanced Effect of Organic and Inorganic Fertilisers (including Compost)Slow Release and Higher Plant Available NPK from High Mineral Ash Chars Derived from ManuresReduced Off-site Migration of Agro-chemicals

CHARACTERISATION OF BIOCHARS;THE CONCEPT OF FIT FOR PURPOSE; Summary ANZBRN/IBI Discussion

1) Feedstock for biochar should be residues with no higher value, or sustainably grown resource (e.g. manures, agrowastes from processing plant, greenwaste)

1) Biomass from non-sustainable sources, or high conservation value ecosystems should not be used.       

2) Biochars from different feedstocks and process conditions vary widely in properties e.g. nutrient and liming value, and stability of carbon. Different biochars are suitable for different applications.

3) Biochar must be safe: must pass standard ecotoxicity (eg earthworm avoidance) and germination tests       

4) Minimise Greenhouse Gas Foot Print Through using Local Biomass Resources, using energy efficiently

5) Production process and biochar product must Comply With relevant OHS requirements, Waste Management Guidelines and EPA Standards

6) Biochar production and utilisation should support sustainable development (e.g. involve local community) and enhance soil health

IMPROVEMENT IN CROP YIELDS

Growth of radish seedlings with biochar from poultry manure with either no nitrogen fertiliser (blue) or applied N fertiliser (red) at 100 kg N/ha. From Chan et al. 2007.

with biochar

without biocharLehmann et al, 2003 Amazonian Dark Earths Photo Julie Major

SEM photographs of the microorganisms in the pore of charcoal of compost in Suwa City. (Shuji Yoshizawa et al)

Effects of Soil Microbial Fertility by Charcoal in Soil, Presentation by, Makoto OgawaProf. Oosaka Institute of Technology

Recent Research Findings

Carbon Turnover Rates

WOOD AND PLANT CHAR TRANSFORMED TO STABLE CHAR

Outside of Terra Preta Particle

Inside of Terra Preta Particle

Corn Stover Char

Wood Char

GREENHOUSE GAS BENEFITS FROM BIOCHAR AND ENERGY

0 5 10 15 20 25 300

20000

40000

60000

80000

100000C

O2 e

quiv

alen

ts (C

O2 a

nd N

2O)(

g/H

a/d)

Time (Days)

Litter Green Waste Control Soil Atmospheric

Lukas Van Zweiten; 2007; Putting carbon back in soil through the generation of renewable energy

Biomass Carbonisation Concept

Source; Amonette J (US Dept of Energy), Joseph S, Lehmann J; Biomass carbonization: The dark side of terrestrial carbon sequestration. NSCE meeting 2007