Martin Wynne pulls what appears to be no more than a lump of blackened wood from a fire with his gloved hands. It’s still steaming from an 800 degree burn followed by a liberal soaking with water.
He breaks it open like a stick of dry bread and crumbles the fresh charcoal into fragments.
“From waste to wealth,” he says. “Black gold.”
Wynne, with the assistance of vigneron Shane Mead from Quartz Hill vineyard, has just made over 1000 litres of biochar in just on four hours.
But what is biochar exactly?
AN ANCIENT METHOD OF SOIL ENHANCEMENT
Biochar is a conglomerate word made from biomass and charcoal.
At its simplest – and the process is inordinately simple – biochar is the end product of burning wood or other plant-based material to a point where it is reduced to charcoal, and not ash.
This is done by subjecting the matter to pyrolysis: decomposing it by introducing gradual degrees of heat. The process of making biochar begins at around 200°C and continues up to a maximum of around 800°C, depending on the matter.
Evidence of the production of biochar has been found in Pre-Columbian cultures, and it’s believed to have originated in Amazonian culture.
I first read about biochar in 1986, but it wasn’t until the drought really kicked in here that my imagination fired up. I thought, ‘I really need to do something’.Martin Wynne
Known as terra preta, Portuguese for ‘black earth’, it has an amazing ability to continually reproduce itself and to revitalise previously poor soil. It attracts and stabilises mycorrhizal fungi, a kind of fungus which allows the transfer of nutrients between a plant’s roots and fungus. It also helps earthworms by grinding nutrients in their digestive system. eliminating the need for them to produce their own calcium.
MARTIN WYNNE – SOIL AND COMPOST GENIUS, GARDENER AND POET
Almost 20 years ago, a fifth-generation Bendigo farmer and gardener and his partner took up 14 hectares of degraded sheep grazing land at Lamplough, between Lexton and Avoca in central Victoria.
Martin Wynne and Pamela Farrelly had met in Victoria’s Yarra Valley, but economics pushed them west – at the height of the millennium drought. Through that awful decade of heat, drying wind and bushfire, the couple persisted with their strategy of ripping the clay soil and loading it with straw and hay; overplanting it with lupins and green manures, and introducing worms and fungi.
Nearly two decades later and the verdant farm is astonishing to behold. Conventional wisdom, indeed even the most passionate of gardeners, would say Wynne and Farrelly have achieved something which should not be possible. In an environment where water is scarce and gum trees take what there is, they have transformed the earth into a garden reminiscent of the south of England.
Fruit trees and swales of lush grass spill over bluestone fences. Vegetables and fruit of remarkable size and flavour grow readily. There is a 30 to 40-centimetre of topsoil: rich, dark, damp and writhing with earthworms, reeking of fecundity.
“I've got some of the best soil on the planet and I've created it myself over 18 years, from marginal, shit country, pardon my French,” Wynne says without a hint of hubris. Rather, his passion shines through. He knows he’s making a difference.
Wynne writes and recites poems of adoration of the earth and the soile. He knows them off by heart, and holds audiences transfixed by his whimsical delivery at open days and farmers’ markets.
Goats, chickens and wildfowl graze contentedly. Weeds are regarded for their beneficence rather than their nuisance value, and dealt with according to the season.
BUILDING A BIOCHAR BONFIRE
It’s a freezing cold morning among the vines of Quartz Hill Vineyard. A chill wind slips through the wires of the naked, pruned syrah. Martin Wynne and Shane Mead, the vigneron and owner of Quartz Hill, clap their gloved hands together, condensation streaming from their mouths. Shane’s dog Monty, a collie-cross, assists by sitting on everyone’s feet at each available opportunity.
There’s a huge pile of torn-out vines lying on the frosty earth next to a rusted-out water tank. Inside the tank is a pile of dry gum leaves and twigs, and alongside it is a metal bucket full of white earth. Wynne quickly lights the pile inside the tank.
“Too cold not to get started,” he says.
As soon as the fire is blazing, Wynne and Mead begin to throw armloads of cut vines into the flames.
“It has to get to a certain heat to begin the process of pyrolysis,” says Wynne.
“We don’t want it to burn too slowly, or all the cellulose won’t be converted; but if it burns too quickly we’ll just get ash. Ash is mostly salt, which is not good for the soil, it’s detrimental.”
For the next four hours the fire is loaded with the waste vines, which settle into a steady and thankfully warming conflagration, stoked by the men. At intervals Wynne and Mead pause to grabs handfuls of the white earth which they toss into the flames.
I've got some of the best soil on the planet and I've created it myself over 18 years, from marginal, shit country, pardon my FrenchMartin Wynne
This is diatomaceous powder, a silica-rich conglomerate formed from the fossilised bodies of tiny sea creatures. It has many uses, but Wynne believes adding it to the fire as a catalyst assists in the better creation of charcoal.
“Well it's because it's silica, I think what's happening is it's melting,” he says.
“And the biochar is sucking it in and giving it more thermal mass, giving it more temperature, because the silica heats more than the carbon. I'm only guessing, but I know it works. It works on the big logs without splitting them.
“All the videos that I've seen on YouTube and on the Internet of people making biochar, it's all been split wood and I thought, ‘well I'm lazy, I can't be bothered splitting it’. So I went back to my encyclopaedia of nature and science and I read about pyrolysis and using a catalyst and I thought, ‘Well I'll give it a go’, and I knew I could get some diatomaceous earth. The first time I tried it, it worked beautifully; I was amazed. I've been doing it ever since.”
The vine pile gradually disappears, and the suffering water tank, glowing red and gradually beginning to disintegrate, fills with blazing charcoal. With a practised eye, Martin Wynne calls a halt when he’s satisfied the biomass is sufficiently pyrolysed.
A SILKY FLOW OF WATER
Shane Mead has the pump in the dam, ready to deliver water as Wynne calls it up. Plumes of steam cascade skywards as the 600°C to 800°C pile is suddenly cooled. Miniature volcanic explosions can be heard as the steam mixes with exploding gases. For about 20 minutes water is poured onto the black coals, killing the pyrolytic decomposition.
At the start most of this water is evaporated by the heat of the pyre. As the biochar cools it begins to soak up the flow. This is the great physical value of biochar, says Wynne: its astonishing capacity to attract and retain amounts of water far in excess of its own size and weight.
As the water flows through charcoal, Wynne gestures to feel it. It has a silky, oily texture, smoother than pure water.
“That’s amazing,” he says.
“That’s the silica mixing into the water,
DON’T JUST BURN OFF
“I'm an environmental emergency worker,” Wynne says. “I'm trying to help the environment, help farmers. Farmers are burning their crops and it's just stupid. It's just a waste of resources; they're depleting their land every time it rains. The soil's washing away, the nutrients are washing into the creeks. Something as simple as making biochar can stop soil degradation.
“I first read about biochar in 1986, but it wasn’t until the drought really kicked in here that my imagination fired up. I thought, ‘I really need to do something’.”
And Martin Wynne is doing something marvellous.