The goal is to create stable soil carbon that is not affected by drought or moisture
An unusual approach to slowing climate change is being implemented on 100,000 acres (40,468 hectares) of Australia’s vast agricultural heartland.
Farmers are trying to take advantage of the superpowers of the small underground branches of fungito extract carbon dioxide from the air and hide it underground.
Entrepreneurs and investors around the world are using various technologies on farmland not only to grow food, but also to “eat” the excess carbon dioxide produced by more than a century of burning fossil fuels and intensive agriculture.
Why fungi? Because fungi act as carbon traders in nature.
While sowing their crops, farmers add a pulverized powder of fungal spores.
The fungus latches onto the crop’s roots, takes the carbon that the plants absorb from the air and locks it in underground storage in a form that can keep it underground much longer than the natural carbon cycle.
The mushroom venture, by an Australian company called Loam Bio, is among several startups that have raised hundreds of millions of dollars in investment in attempts to use the soil to remove carbon dioxide from the atmosphere.
“It’s pretty simple,” is how a fifth-generation Australian farmer named Stuart MacDonald described his experience while sowing fungal spore dust with his wheat and canola seeds on his farm near Canowindra this year. “We are not asked to do anything special. It’s not a big capital outlay, either.”
Soils are the second largest store of carbon after the oceans
The potential to remove carbon from soils is enormous.
Soils contain three times more carbon than the atmosphere and can potentially absorb more than 5 gigatons of carbon dioxide per year, or one-seventh of all the carbon dioxide that human activity injects into the atmosphere, according to the Intergovernmental Panel on Climate Change.
This makes them the second largest carbon store in the world after the oceans.
“I think soils will play a key role,” said Rob Jackson, a climate scientist at Stanford University, although he was skeptical about whether the promise of fungal supplements in field tests could have a statistically significant effect on working farms.
Loam Bio’s fungal talc has been spread over 100,000 acres in Australia this year, with 250,000 acres expected to come online next year.
Half a dozen farmers in the United States are trying the product in their soybean fields.
Field tests are underway in Canada and Brazil.
Critics are concerned that new technologies are treating the symptom, not the cause, of climate change.
Why Australia?
Not all farmers “sow” fungi out of altruism.
More carbon means better soil health and better yields.
But in Australia, farmers have another motive.
They hope to profit from government-issued credits if they can prove they have stored carbon underground.
Critics said carbon credits were awarded not for substantive changes but for seasonal fluctuations in weather: In unusually wet years, carbon builds up in the soil, only to dissipate in dry years.
A study has warned that the number of carbon credits issued for agricultural projects is inflated.
The different forms of carbon
Accounting for soil carbon is complicated by the fact that it comes in different forms.
Most of the carbon in soil is in the form of highly volatile organic matter.
In agricultural land this would be crop residues or manure.
Carbon can return to the atmosphere after a few years, or a drought or fire can burn it even faster, releasing carbon dioxide back into the air.
But there are more stable types of soil carbon, including some that attach to minerals and stay there for a century or more.
Loam Bio says its fungal spores can help build this more stable soil carbon.
They measure it for their farmer customers using soil cores one meter deep.
Fungi do the vital work underground.
They take the carbon dioxide that plants extract from the air during photosynthesis, hide it underground, and return the nutrients that plants need.
Patience is needed for the result
For Alan Richardson, a soil biologist at the Commonwealth Scientific and Industrial Research Organisation, a government agency in Australia, the concept of using fungi to store carbon underground makes sense.
But this will only work if farmers apply the fungi year after year, allowing the soil to accumulate carbon over many years.
“The fundamental principle behind it is sound, but whether it will translate into practice, we don’t know,” he said.
Still, Steve Nicholson, a farmer near the town of Forbes, is so optimistic about the prospect that he signed a 25-year contract with Loam.
“It’s a bet,” he said. “But it’s a very, very good bet.”
Loam technicians measured his baseline soil carbon in February, at the peak of the hot, dry season.
They will return next February to find out if its soil carbon has increased and to determine how much of it is in the more stable forms.
Loam Bio tells its customers they can expect to store one to two tonnes of stable carbon per hectare.
Australia’s state-owned Carbon Credit Agency will have to check how much carbon Nicholson has added before issuing credits.
Nicholson hopes to win by next July.
Its income will depend on the price of carbon in Australia at the time.
He expects more than A$100, or about $65, per hectare.
A New York Times publication
#Australian #farmers #sow #fungi #wait #profits #carbon #credits
