A recent Manitoba study shows wind erosion may not be the soil stealer it’s cracked up to be.
“It’s a perception issue,” said David Lobb, a soil scientist from the University of Manitoba.
“In terms of soil loss, which is how wind erosion is almost always characterized, there is very little evidence that wind erosion results in significant soil loss,” Lobb said.
Lobb recently wrapped up a two-year study on how land rolling for soybeans affects wind erosion. This was done near Brunkild.
Just under 1.8 million acres of soybeans were seeded in Manitoba in 2018, according to MASC statistics. It’s common to roll soybean fields to flatten the ground and make harvest easier, especially in stonier areas.
However, considerable concern has been expressed that rolling contributes to wind erosion, according to a handbook for a recent Soil Conservation Council of Canada conference. Reduced surface roughness allows wind to gather more speed along the soil surface.
The study assessed the effects of land rolling on soil properties like surface roughness, surface moisture and crop residue cover. It studied the actual transportation of wind-eroded sediment and potential for soil loss.
It also looked at the abrasion of soybean plants by windblown sediment to assess the impacts of wind erosion on crop health and yield.
“There is wind erosion and sediment blowing occurring,” Lobb told the Manitoba Co-operator. “Just not much during the growing season — when wind erosion risk is high is often before seeding and land rolling occurs.”
Lobb added that there is increased risk of erosion from rolling for two to four weeks after seeding, but once the soybeans sprout, this risk decreases. The exception might be a large wind event, but even then the loss may not be substantial.
“Last year when we had our biggest wind erosion event in recent memory, we saw almost no sediment coming off the fields we were monitoring and very few fields across the (Red River) valley. There was dust in the air, but this does not always mean a lot of soil loss.”
Lobb said they went into the study not anticipating much evidence of massive wind erosion, and warned the soybean producers of this. However, he said a “non-result” is valuable too.
He added that “snirt,” the typical example of wind erosion, is conspicuous but may represent “next to nothing” in actual soil loss.
In contrast, Lobb said tillage is an actual soil movement problem. Tillage, rather than wind, fills in surface drains and causes soil to roll into ditches “every year along every mile,” said Lobb.
However, Lobb said wind erosion does cause problems that should concern farmers.
“Abrasion of crops is a concern even if the soil loss rates are low,” he said. “So are health and visibility concerns. These can be serious concerns even if the soil loss rates are very low.”