An initiative by a South West Landcare group more than ten years ago has stimulated significant change in both the avocado and dairy industries.
In 2010, Kathy Dawson of Southern Forests Community Landcare (SFCL, then Warren Catchments Council) held a workshop featuring Dr Syd Shea, who was with the Rainbow Bee Eater Project at the time) to speak about biochar research in the Wheatbelt, including the work being undertaken by Dr Paul Blackwell.
“We had local members very keen on utilising biomass to make biofuels and biochar,” Kathy said. “There were also sawmillers looking at it as a value adding opportunity.”
With the emergence of carbon farming around that time, some attendees saw biochar as a potential carbon sequestration method, including local farmer Doug Pow.
“I didn’t know Doug before that. We started talking about biochar and dung beetles, and other applications for biochar. There was a bit of a groundswell. We started a group we called Warren Biochar and joined the International Biochar Initiative, which is an enormous font of information.”
Doug started feeding biochar to cattle by mixing it with molasses (later glycerine), feeding it out in drums and promoting dung beetles to bury the biochar. He received funding from South West Catchments Council (SWCC) to attend the Biochar Fest in Mullumbimby in 2014 where he met Dr Stephen Joseph, professor at the University of New South Wales, who went on to conduct research on Doug’s property into the effect of feeding cows biochar.
To raise its profile and interest from research organisations, SFCL received a small State NRM grant to replicate Doug’s practice at local dairy Bannister Downs, where it could be implemented on a large commercial scale.
“We described the demonstration at Bannister Downs to the Australia New Zealand Biochar Conference which led to the practice being adopted by the Fleurieu Milk Company who did further testing.”
While news of Doug’s feed innovation was circulating, he was looking at other applications, including whether the physical properties of biochar could be incorporated into an avocado orchard to mimic volcanic andosol soils from the avocado tree’s natural habitat where soil bulk density is low and oxygen high.
In 2014, SFCL received funding from SWCC for the biochar in avocado orchards project to test Doug’s theory.
“It was a small budget over 4 years, so there was a lot of volunteer work. But without the funding, the practice may never have got off the ground.”
Doug planted two new rows of avocados, 36 in each row in November 2014. Before planting, the soil was removed from one row to a depth of 600 mm, biochar added, and soil backfilled to form two layers. Both rows were then rotary hoed.
“By September 2016, measurements showed that treatment trees were more advanced with average girth and height both greater compared to the control trees.
“Fruit was harvested in 2018, with counts indicating earlier development. The biochar treatment row yielded 3,200 avocados compared to 1,208 in the control. Then in 2019, the biochar row yielded 6,321 compared to 5,306, again out-yielding the control despite avocados typically being biennial bearers.
“Farmers coming along to field days were convinced that there was something in it.”
Kathy doesn’t know exactly how widely the practice has been adopted, but says a lot of semi-trailers with biochar fines have come in from Simcoa in Kemerton where the biochar is produced. The fines are a waste product from Simcoa’s smelting operation because they are too small to be used as a reductant agent.
“In addition to avocado growers, biochar has since been used in citrus, kiwi fruit, stone fruit, olives with a salinity problem and vineyards.”
Kathy engaged local engineers to fabricate a kiln to make her own biochar. While personal kilns may reduce freight costs, quality control is an important aspect of production.
“Different facilities have different capabilities and the more they are refined, the better they can remove contaminants from the product. Mine is not capturing condensates and converting them into pyroligneous acid (wood vinegar), which is another product.”
Spreading is another barrier because biochar needs to be incorporated into the soil.
“Broadcasting it is a waste of time, it just blows all over the place. Carbon Ag Solutions have agreed to incorporate it in their compost granule, and this is how it needs to be used, or as a seed coating mix or a fertiliser granule so it can go through machinery.
“The process needs to be fit for purpose. In the broadacre situation, a machine, such as the Krone 5000 can follow the harvester and pelletise the waste. Ideally a mobile pyrolysis unit can batch process the uniform-sized feedstock and produce biochar that can be re-incorporated on-farm, closing the carbon loop. In the South West, where timber waste is more likely to be the feedstock, the wood would need to be chipped for it to be augered into a mobile unit.
“A standalone unit that supplies heat or energy to a co-located operation as well as producing biofuel, syngas, biochar and wood vinegar is an ideal set up.”
Biochar is still finding its feet, but it’s a credit to Kathy and the Landcare community to have sown the seeds of innovation, developed networks, raised awareness and helped farmers like Doug achieve their aspirations. Landcare groups don’t purport to be research organisations, but they can help industry and research organisations recognise the possibilities and partner with them to help innovations grow.