Winds of change: conservation tillage clears the air

Moisture conservation | Direct seeding and decline in summerfallow reduce soil erosion

Prairie farmers have moved from sodbusters to dustbusters.

A research paper published in January shows the increase in direct seeding and reduction in summerfallow have dramatically re-duced dust in the air.

That may seem obvious to some farmers, but research undertaken by Thomas Fox, Thomas Barchyn and Chris Hugenholtz confirms a marked reduction in airborne dust since 1990.

Hugenholtz, a University of Leth-bridge assistant professor and re-searcher, said the study was prompted by studies elsewhere in the world that showed major increases in dust levels. His research team decided to see if there was a similar trend on the Prairies, particularly in the Palliser Triangle and its environs.

They collected dust and climate statistics from seven prairie sites from 1961 to 2006 and got a surprise.

“When we put them all together, region wide, all of a sudden around 1990, it flat lined,” said Hugenholtz.

Given the variability seen in the 1961-89 period, his team initially thought something was wrong with the data. When that proved not to be the case, they attributed the marked change in 1990 primarily to the effects of conservation tillage.

Farmers, doff your hats.

“We believe they effectuated that change, which showed up in the dust at about 1990,” Hugenholtz said.

“The dust really changed, probably because enough of the land coverage had either adopted direct seeding or reduced summerfallow to really kind of suppress dust from that point forward.”

Agriculture Canada’s analysis of tillage trends shows no-till and reduced till practices became a statistical factor in the early to mid-1980s.

Benefits of increased crop yield associated with moisture conservation, reduced labour and reduced soil erosion became well documented.

“No till and reduced till systems have and will continue to be significant beneficial management practices across Canada,” said an Agriculture Canada report on reduced and zero tillage.

However, it also noted some constraints to further adoption, including excess crop residue, weed control issues and special crops that require different field operations.

Although there are still dust storms on the Prairies and dust in the air, Hugenholtz’s research shows there is definitely less dust than the pre-1990 period. He said the information is useful for future planning, but also for its confirmation.

“We often lack demonstrated evidence of efforts in soil conservation. You can see them sometimes at the field scale, but it’s hard to see it region wide. I think the outcome of this is really of demonstrating the success of (soil conservation) efforts.”

The research paper, Successes of Soil Conservation in the Canadian Prairies Highlighted by a Historical Decline in Blowing Dust, notes that 1990 was a threshold year, when soil conservation efforts materialized through a marked reduction in dust.

“This suggests that farmers on the Canadian Prairies are better equipped to handle conditions with moderate climatic erosion forcing now than in the 1980s,” the paper reads.

“However, results also show that it may be difficult to completely eliminate wind erosion; extreme droughts and/or windy periods will always result in some wind erosion as in the droughts of 2001–02, for example.…

“Our interpretation is that the strong reduction of dust after 1990 represents a region-wide threshold crossing, whereby the progressive shift in soil conservation practices began effectuating a change in the dust frequency.”

The report is available online.

About the author

Comments

explore

Stories from our other publications