Biochar – baked not burned

The Australia and New Zealand Biochar Researchers Network delivered a workshop on Monday 28 June – an opportunity to learn basic facts about biochar and its potential applications and benefits.

Biochar can be produced from a wide range of organic materials – wood waste, paper waste, municipal green waste, animal manures and crop residues, to name a few.

(Click on graphic to enlarge.)

Biochar is organic matter that has been “baked” in a low-oxygen environment to form “charcoal”. It is a very stable, carbon-rich (>50%) substance.

The biochar production process is detailed on the Pacific Pyrolysis web site:

How could biochar help the environment?

Biochar production converts relatively unstable, short-lived forms of carbon (such as vegetation) into stable, long-lived carbon compounds (100 to 1500 years typical lifespan). By converting atmospheric CO₂ into vegetation (a natural process), and vegetation into biochar, atmospheric carbon is “locked up” for centuries.

When feedstock materials are heated in a low-oxygen environment, a process called “pyrolysis”, they give off a range of flammable gases – “syngas”. Syngas from biochar generation is burned to produce heat and/or electricity for industrial and domestic use. Energy generation from syngas offers significant opportunities to offset generation from fossil fuels.

When biochar is added to soil, it may reduce “off-gassing” by the soil of nitrous oxide, a powerful greenhouse gas derived from conventional and organic nitrogen fertilizers.

If biochar production can use material from traditional waste-streams such as biosolids and municipal waste, then it offers opportunities to reduce landfill and sewage outfall.

How could biochar help agriculture?

Depending on the feedstock and pyrolysis process, biochar may offer a wide range of benefits as soil conditioner when incorporated in arable soils. Biochar applied at 10 to 50t/ha has been found to offer benefits including:

• Increased soil water holding capacity
• Increased crop production
• Increased soil carbon levels
• Increased soil pH
• Improved efficiency of fertiliser use by plants.

Can I make biochar at home?

No. Uncontrolled domestic production of “biochar” is polluting and is not a safe or sustainable practice.

Can I put charcoal from the fire on my garden or in my pot plants?

Yes, but it is unlikely to offer the benefits of biochar.