More agricultural sectors are trialling biochar to improve soils and production and recycle carbon back into the soil, as beef, dairy and cropping studies continue to show promise.
Biochar looks like charcoal but has a large surface area that is porous and bioactivated.
It is produced through the pyrolysis of biomass waste like grape marc, wood chips, almond hulls, fruit peels and straw.
It contains up to 80pc carbon and has been shown to enhance soil health, nutrient retention and water holding capacity.
A farm manager, consultant, researcher and Australia New Zealand Biochar Industry Group chair Melissa Rebbeck says the product also had big benefits on animal health and production in Fleurieu Peninsula beef and dairy trials.
ANZBIG hosted a biochar field day and forum in SA facilitated by Ms Rebbeck, including a visit to Metamorf Engineers, makers of CharCell biochar machines that are in use in fruit, almond and vineyard settings.
In beef and dairy settings, Ms Rebbeck has led trials using biochar as a feed additive and also as a soil additive in a bid to improve pasture production.
In a trial on a 250-cow dairy herd on the Fleurieu Peninsula, biochar was incorporated into a feed mix at 150 grams a head per day.
Across a 12-month period, milk production was increased by 0.4 to 1.4 litres per animal per day.
Ms Rebbeck said the overall profit increase equated to $35,000 plus fodder savings.
"We didn't include improvements in pasture production (in the trial) but we did some anecdotal tests in the soil and we also found there was improved pasture health and biomass," she said.
"Hence we went on to do a further replicated trial to validate these findings.
"Because he had populations of dung beetles, we believe the biochar in the manure was being buried by the dung beetles.
"We tested the manure and even that was higher in nitrogen, phosphorus, potassium and calcium compared to the manure of animals that hadn't been fed biochar."
In the subsequent trial at Mark Higgins's beef enterprise, Ms Rebbeck investigated the potential soil health benefits of incorporating biochar into paddocks through dung beetles.
Plots were established with biochar in manure, biochar under manure, straight manure and no manure.
This was followed by pasture health and production tests some time later.
"We found better phosphorus in the plots where biochar was in the manure, we found increased soil pH, increased production, more mycorrhizal fungi and most importantly increased carbon," Ms Rebbeck said.
"The plots with straight manure did ok and increased soil carbon but didn't have that multiplier effect the biochar provides."
So what is it about biochar that leads to these improvements?
"One gram of biochar has the surface area of a house and that whole surface is electron mediating and is redox active," Ms Rebbeck said.
"In high energy diets like feedlots and dairies that redox active process is really important for nutrient and mineral uptake, in addition to absorption of heavy metals and toxins."
While the impact of biochar can vary on what biomass is put through the pyrolysis process, Ms Rebbeck said there were "five-fold benefits" for beef and dairy pasture production systems - increased production, increased water-holding capacity, improved soil health, increased nutrient retention and a potential payback from soil carbon increase.
Ms Rebbeck said the ability to increase soil carbon was a reason biochar could also play a role on broadacre cereal farms.
BUSINESSES LOOK AT PRODUCTION FIT
Agricultural businesses with significant waste and the need for heat energy are in the early stages of investigating how biochar production could fit as another arm of their enterprise.
Riverland Almonds Hulling has a CharCell Three pyrolysis unit turning almond hulls into biochar, while there are also trials happening in winemaking and forestry enterprises.
Metamorf Engineering managing director Steven Hill said there were currently two CharCell Three units being used in Australia and a third in New Zealand.
Agricultural waste like wood chips, grape marc, nut shells or oat husks are put into the CharCell through a feed system and the material is pyrolyzed without oxygen, using thermal energy from the self-sustaining combustion, to produce biochar.
The process also produces significant thermal energy so Mr Hill said businesses who were able to harness that energy - like food processors - could make the economics stack up and receive significant revenue from biochar sales and carbon removal certificates..
"The Charcell Three is robust and engineered for 24x7 operation. It's low cost and compact in size," Mr Hill said.
"Some of the projects we're looking at are about a year to payback the machine costs, particularly where you've got full utilisation of the heat being produced."
