How your fallen leaves can be used to fight climate change

A man from Almonte, Ont., wants people to donate bags of fallen leaves so he can use them to make a fungal dominant compost he says can both increase productivity on farms and fight climate change.

Scott Hortop says fungal dominant compost has potential to increase crop yields, too

Scott Hortop shovels leaves into his Johnson-Su bioreactor where they will break down into a fungal dominant compost. (Robyn Miller/CBC)

Instead of bagging up and hauling fallen leaves to the curb, Scott Hortop hopes you dump them on his property.

Hortop, who lives in Almonte. Ont., just west of Ottawa, says he wants to use the leaves to make a fungal dominant compost he says can both increase productivity on farms and fight climate change.

"I have got 13 grandchildren and I feel a compulsion to do something for the climate emergency," Hortop said.

His backyard will soon have eight bioreactors to make the compost. The cylinder-shaped containers each have about six chimney-like pipes stuck in the middle to allow airflow and prevent the compost from having to be turned.

These pipes act like chimneys to allow the material to be composted aerobically. (Robyn Miller/CBC)

After about 18 months Hortop said the result will be soil rich with fungi, featuring an equal amount of bacteria.

He said the compost acts as an inoculant for degraded soil, which improves both crop yields and carbon sequestration.

"I feel very fortunate to have something real and something physical I can do about climate because I think we're all sort of caught waiting for policy leadership ... and this is something many people can do," Hortop said.

'Agriculture of the future'

The method called Biologically Enhanced Agricultural Management (BEAM) was developed by David Johnson and his wife Hui-Chun Su Johnson.

Johnson, a molecular biologist and research scientist at New Mexico State University in Las Cruces, N.M., said farmers around the world are experimenting with the compost on their crops and seeing positive results.

"Since it is more profitable, we think that it will be adopted by a lot of people," Johnson said.

"I think that it will become the agriculture of the future."

Hortop wets the leaves before he puts them in the bioreactor. (Robyn Miller/CBC)

Johnson pointed to a rancher in Australia who applied the compost to one side of a fruit tree and watched it blossom out one month ahead of the other side.

"This is not your normal compost. We don't apply it tonnes per acre. We apply at two kilograms per hectare. And with that, just at two kilograms per hectare, we are seeing results," Johnson said.

He said a project in Wilcox, Ari., showed an increase of about 10 tonnes of carbon per hectare in just one year.

"This will handily solve our issue with atmospheric CO2 (carbon dioxide)," he said.

WATCH | The benefits of the method: 

Why your fallen leaves could play a small part in mitigating climate change

1 year ago
Duration 1:18
Almonte, Ont. resident Scott Hortop takes fallen leaves and makes a compost rich with fungus that helps add nutrients to depleted soil and reduce its carbon emissions.

Since the pandemic began, Su Johnson said she and her husband have been inundated with questions from people watching their YouTube videos who want to make their own Johnson-Su Bioreactors.

"The end result is that we have happy farmers, we have [a] better environment and we have better food," she said.

Convincing farmers to give it a try

Alberto Suarez Esteban runs Nature's Apprentice, a small organic farm in Pakenham, Ont. He said he plans to make his own fungal dominant compost.

Esteban said he already saw results when he tested some of Hortop's compost on a few of his vegetable beds this spring.

The owner of Nature's Apprentice farm in Pakenham, Ont., said he plans to make his own fungal dominant compost. (Robyn Miller/CBC)

"You could really tell the difference between the plants that had the compost and the plants that didn't have the compost," he said.

Esteban, who also teaches conservation biology at Carleton University, said he began to farm to help support biodiversity and mitigate climate change, so being able to store as much carbon in the soil as possible is "crucial."

"Also, because of my sandy soil, the more carbon I have in the soil, the more water stores and the less I need to irrigate," Esteban said.

Now he and Hortop are trying to spread the word about the benefits of fungal dominant compost to other farmers in the area.

Alberto Suarez Esteban said he began to farm to help support biodiversity and mitigate climate change. (Robyn Miller/CBC)

While some have shown interest, Hortop said others are more hesitant, a sentiment Esteban understands.

"It's a very risky profession. Like you can do everything right and then not get a crop. So I guess that's a barrier for people," Esteban said.

"But I think it'll take a few of us to try it out and show that it has benefits and hopefully people will sort of pick [up on] it and try it."


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