What is Biochar?

27th Nov 2022 | 

Biochar is a great tool in combatting climate change and soil infertility- so how exactly does it work?

“If you could continually turn a lot of organic material into biochar, you could, over time, reverse the history of the least two hundred years… We can, literally, start sucking some of the carbon that our predecessors have poured into the atmosphere down through our weeds and stalks and stick it back in the ground… We can take at least pieces of the Earth and… leave them better than we found them.”- Bill McKibben, author and climate activist. 

Image: Greenside Farm uses biochar as part of their sustainable agriculture practices.

What is Biochar?

Biochar is created when biomass (plant matter and agricultural waste) is burned in a low oxygen environment such as a kiln, turning it into charcoal. This process of pyrolysis creates charcoal which can be put back into the soil to improve its health- among other benefits.

History of Biochar

Indigenous cultures have been using biochar for thousands of years. In the Amazon, for example, the process is known as Terra Preta and could have started as early as 2,500 years ago! Back then, people are believed to have ignited and then buried organic material to create the low-oxygen environment required. This provided a solution for their soil infertility. Still to this day, Terra Preta soil is fertile and nutrient rich, much more so than the soil in nearby areas.

Nowadays, biochar is created in a kiln (below).

Image: Biochar Kiln Diagram Souce: Research Gate


Benefits of Biochar

Biochar is bustling with benefits. There are three top reasons that it's so valuable:

         1. It can improve soil quality on farms and in the garden, promoting crop growth and health.

         2. Biochar is very stable, and can store carbon for hundreds, even thousands of years, as opposed to releasing it into our warming atmosphere. This makes it a relatively immediate solution in reducing the impacts of farming (including agricultural waste) and climate change.  The Intergovernmental Panel on Climate Change's Special Report      On Climate Change and Land (2021) found that it can help build organic carbon in soil by up to 20%, and reduce nitrous oxide emissions from soil from 12%-50%.

         3. It is a source of renewable energy. While 50% of the kiln contents will be biochar, the other half is biofuel- which can be used as a fuel source.

Biochar has been known to reduce soil salinity and improve water retention. It helps people, but also our smaller friends- earth worms and fungi- benefit too!


Image: Mushroom has attached to biochar material. Source: Josiah Hunt

If you're interested in utilising biochar, Biochar International has a handy guide to get you started. 

Landcarers and Biochar

'Shit to Gold'- 24 Carrot Gardens 

24 Carrot Gardens are undertaking African Boxthorn removal from Green Point, working with social enterprise Your Town and Bridgewater Landcare Group to turn the weed into biochar.  This project is supported by our Tasmanian Landcare Fund round 24. 

Greenside Farm 

The Baxter family have a 'no-nonsense' approach to biochar making which they showcased at the 2021 Tasmanian Community Landcare Conference.  Sustainable agriculture is key to the way that Jenny, Brian and Will run their farm. Biochar, composting, riparian rehabilitation, and shelterbelt plantings are all part and parcel for this team. 

The New Black Biochar

The New Black Biochar is a Tasmanian organisation focused on the benefits of Biochar. Founded by Agricultural scientist Christina, and mechanical engineer Bodie, they connected through a shared set of values : environmental protection, sustainable resource use, and circular economies. They have now developed a biochar kiln, involving UTAS engineering students and partnering with Landcare Tas to deliver training workshops. You can read more about them here. They have lots of handy resources for getting started with biochar, including how to use biochar in your garden.