Soil degradation is dirty business

Hey there, time traveller!
This article was published 26/8/2017 (1768 days ago), so information in it may no longer be current.

Opinion

Soil conservation advocates got tremendous media mileage out of the "soil your undies" campaign they mounted earlier this year.

Sexy it was not, but there was something about the idea of planting a pair of "tighty whities" in the dirt that captivated the public’s imagination. Farmers, urbanites, columnists, students and 4-H’ers across the country couldn’t resist the call to try it out.

The more chewed up the underwear emerged after being buried, the greater the microbiological activity, or life, there was beneath the surface, which is a measure of the soil’s health.

But as the Soil Conservation Council of Canada met in Guelph last week for a summit on Canada’s soil health in 2017, there was a high level of frustration over how protecting the soil continues to be a low priority after nearly a century of soil conservation efforts.

That’s not to say progress hasn’t been made. The situation today is a far cry from the Dirty Thirties, when wind erosion created creeping waves of soil that choked out vegetation, threatening to turn a vast area of the Canadian Prairies into a desert. Conditions were forcing outward migration with far-reaching impacts, both to the region’s and the country’s economy.

Governments moved in, primarily by creating the Prairie Farm Rehabilitation Administration (PFRA), an agency devoted to developing tools such as shelterbelts, on-farm water storage and ground-anchoring varieties of vegetation to reclaim the Prairies for agriculture.

In the 1970s, farmers graduated away from summerfallow to continuous cropping. The evolution of farm equipment — and better, more affordable herbicides — helped them reduce the deleterious impacts of tillage.

But it’s as though farmers and governments alike have concluded their work in this area is done.

The PFRA was disbanded. Shelterbelts are being ripped out across the Prairies almost daily and the amount of tillage taking place is on the rise, as are other soil-health indicators such as salinization. Instead of becoming more diverse, crop rotations on many farms are narrowing.

It’s generally accepted that the less tillage or soil disturbance that takes place on the land, the better it is for soil health.

Don Reicosky, a retired U.S. government soil scientist, said while the concept of zero tillage remains the ideal, most of what is practised today is called "conservation tillage," defined as leaving 30 per cent of the previous crop’s residue intact.

To him, the very phrase is an oxymoron because it still leaves 70 per cent of the surface exposed. As well, many of the tillage tools in use today destroy life below ground, even if they leave the surface relatively intact.

He’s calling for a much broader approach — more diversity in crop rotations, continuous plant growth and minimal soil disturbance.

David Lobb, a soil scientist with the University of Manitoba, said even though annual soil loss has been reduced significantly, degraded soils continue to cost Canadian agriculture a bundle.

The area threatened by soil erosion has shrunk, but more high-value crops such as potatoes are grown on highly erodible lands and under management that leaves those soils exposed to wind and water erosion.

As well, little, if anything, has been done to regenerate soils that were damaged in the past. Increased fertilizer use and genetics might help mask the effects, but common crop-production methods don’t contribute to healthy soil.

Lobb has used available data and modelling to place an economic value on the ongoing lost productivity due to degraded soils, such as those bleached-looking hilly knolls you see where the topsoil either blew away or was moved into gullies by tillage or water erosion.

Lobb measured only the cost to yields, not the indirect costs such as cleaning out ditches filled with drifted soil or the impact erosion has had on water quality.

Even so, the numbers are shocking. He estimates degraded soils are costing the agricultural economy more than $3 billion a year.

"We have reduced soil loss, but we haven’t reduced the history of soil loss," Lobb said.

It’s going to take more than a PR campaign to turn that around.

Laura Rance is editorial director for Glacier FarmMedia. She can be reached at laura@fbcpublishing.com or 204-792-4382.