Biochar trials food for thought

Biochar researcher Dr Lukas Van Zwieten (right) and senior technical officer Josh Rust with a handful of the black gold.

Biochar researchers have expanded their research to around 350 sites on the North Coast, including coffee, macadamia and sugar cane farms.

Principal research scientist Lukas Van Zwieten said trials at the Wollongbar Primary Industries Institute had shown a 100% increase in the production of corn and faba beans and significant increases in nitrogen in the soil, whereas other trials had shown no significant influence from the biochar.

Biochar is a charcoal-like substance made from organic waste that can enhance soil productivity and store carbon.

“Different biochar have different properties depending on the material they are made from and the processing conditions,” he said.

Biochar is made from a process called pyrolysis, which is the decomposition of organic matter at high temperatures in the absence of oxygen. The biochar used in the field studies has come from Sydney, or in some cases has been imported from the Philippines, which makes it very expensive.

“It limits the size of the trials we can do,” Dr Van Zwieten said. “We’d love to do large field trials, but we’re limited to scientific rather than farm demonstration trials.”

Dr Van Zwieten said many of the practices and principles they are developing here will be applicable across Australia and on a global scale to boost food and fibre production, and they have a joint project with the Australian Centre for International Agriculture, where they are trialling the technology in Vietnam.

Dr Van Zwieten has also been involved in researching 34 sites along the Murray River near the Victorian and NSW border, where they have discovered terra preta soils, similar to those created by the ancient Aztecs in the Amazon basin.

“These sites date back 1600 years when Aboriginal people were cooking in earthen ovens and the charcoal would build up over years. We found that the carbon concentration in the soils there is five to six times higher than in the soils next to it, which adds to the evidence that biochar or charcoal can be used to store carbon in temperate soils,” he said.