Keeping it in the ground

A Dalhousie-led group of university researchers is working to map one of our biggest assets in our fight against climate change – our soil.

A map of soil organic carbon of the Maritime Provinces generated using remote sensing data and machine-learning approaches. Darker areas represent higher soil organic carbon. Photo courtesy of Travis Pennell

Soil is as critical as the air we breath and the water we drink. So says a 2024 Canadian Senate report on the importance of soil in terms of our country’s economic, environmental, human, and social health.

It’s also a critical nature-based solution for combating climate change.

Perhaps news to the average Canadian, it’s anything but to Dalhousie University’s Dr. Brandon Heung. An associate professor in the university’s Faculty of Agriculture, Heung, thanks to a $6.9 million Government of Canada grant awarded to the university in 2024, finds himself the lead researcher on a nation-wide, Dalhousie-led research program to monitor and map soil data across the country.

Heung and fellow researchers at Dal will be working with eight other Canadian universities to collect crucial data necessary to supporting mitigation strategies that recognize the potential of soil as a carbon sink.

Canada, says Heung, is about 20 years behind the rest of the world when it comes to soil surveying and mapping, with other countries having already transitioned to digital soil mapping techniques.

“So, the national project is really designed to bring us to that same level, to a point that is like Europe and Australia, for example, and we’ll be able to use the data to support climate change mitigation strategies using these soil-based approaches,” he says.

A complicated subject, the central tenant is that soil security, not only critical in terms of agricultural use and food production, is also crucial for the preservation of biodiversity, water security, climate change mitigation, and as Heung so eloquently points out, “All the other aspects of life [on this planet].”

At the heart of the project is the creation of the Canadian Soil Data Portal — a national soil database and mapping system created using new technologies such as satellite imagery and relatively new methods in digital soil mapping. A database that will allow researchers to know precisely where the opportunities for and the threats towards soil carbon sequestration are.

“The data infrastructure allows us to figure out how much and where we can put the carbon into the ground. Because it’s not going to be the same throughout the country,” Heung says.

The national soil mapping and indexing initiative is as a direct result of the report from Canada’s Standing Senate Committee on Agriculture and Forestry.

“In three of those senate report recommendations, they refer specifically to the need for better soil data in the form of a national soil database and they also talk about the importance of soil surveying to provide the basis for monitoring our resources,” says Heung. “Our project is really designed to address these goals.”

Heung says that given the size of our country the costs associated with nation-wide surveys of soil resources is economically unsustainable so it’s crucial to use data that’s been collected in the past, which, when combined with new data will allow the team to develop high-resolution national maps of critical soil properties

And in terms of the larger picture of climate change mitigation, its importance is in its potential.

“I think it will play a large part [in fighting climate change], because it allows us to pinpoint where on Canada’s landscape we should prioritize actions for addressing issues or implementing strategies that will improve uptake,” Heung says.

That uptake, says team member, Derek Lynch, is a somewhat complicated affair.

Lynch, a retired adjunct professor in the Dalhousie Faculty of Agriculture says one of the main groups they’re targeting in their work to sequester more carbon into the soil while limiting the release of CO2 into the atmosphere are farmers. Farmers, he says, are much more familiar with the term “soil organic matter,” which Lynch points out is “about 50 per cent carbon, so a big sink, technically, a big potential to store carbon”.

And that carbon, contained in that soil organic matter, says Lynch, is the literal energy for most of soil life.

An example of straw cover being placed on a harvested winter wheat field, with straw placed in rows called windrows. Photo courtesy of Derek Lynch

“It’s got a huge biological function, and acts as a kind of glue, holding soil structure together,” he says. “It really is the key to soil health.”

Much of the work with farmers, says Lynch, especially here in Atlantic Canada, is around working together to explore alternative possibilities to what he calls “intensive farming,” where very little residue is returned to the soil.

“There’s quite a bit of range of management, from one farm to the next, where you know, they’re producing the same crops, but one farm might be less intensive; in other words, using more regenerative agriculture processes,” he says.

Those regenerative processes include less tilling, adding cover crops into the crop rotation, leaving straw or other crop residues on fields, and possibly having a forage crop every few years.

“It’s four or five principles that all together are very soil-focused and very much actually about managing soil health and soil carbon,” Lynch says.

So, at the end of the day, it’s about creating a soil database, but it’s also about how to best keep carbon in that land and out of the atmosphere going forward.

“When it comes to carbon sequestration, soils are the largest terrestrial reservoir of carbon,” Heung says. “So, if we really want to fight and mitigate climate change, we have to find ways to put that atmospheric carbon back into the ground.”

Interested in this topic? Check out our 2024 article A More Sustainable Farming Model

Climate Stories Atlantic is an initiative of Climate Focus, a non-profit organization dedicated to covering stories about community-driven climate solutions.

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