Timmerman trains the Tiger Hills of Treherne

A Manitoba farmer has seen major yield improvement by recapping his hills with topsoil from his lower land

Dallas Timmerman farms in the Tiger Hills around Treherne, Man., and sometimes those tigers need training.

“We have a lot of hills and sometimes you need to be aggressive with them,” he says.

Timmerman’s chair and whip are a Leon scraper and Versatile 4WD. He started training his hills over a decade ago, working on just a few at a time. “I was motivated because I saw these hilltops eroded down to gravelly shale and clay, and I had nearby waterways that were full of topsoil,” he says. “So I borrowed my uncle’s scraper and took soil from the in-field surface drains and field edges and put it on the hilltops.”

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It seems so simple, and he says it works.

“I definitely see a difference. By clearing out the water runs, I have better drainage so the low areas are more productive, and I get better yields on the hilltops.”

Timmerman estimates he has rejuvenated 50 acres of hilltops. He puts six to eight inches of topsoil on each hill and then cultivates it to even it out and break up clumps. “Working in the fall, soil can be moist and almost frozen. You need to use the cultivator or a couple passes with the harrows before seeding or you won’t see much benefit that first year.”

As for a time commitment, “it takes me about 30 minutes per hill,” Timmerman says. He also spreads manure from his cattle operation on the hilltops, which adds to their increased productivity.

Keys to regeneration

These steps — adding soil and manure to hilltops — are essential to regenerate our degraded soils, says David Lobb, soil scientist and professor of landscape ecology at the University of Manitoba. “Farms on the Canadian Prairies are still suffering from soil degradation that occurred up to the 1970s and ’80s, and just going to zero tillage didn’t solve the problem,” he says. “We still can’t grow a crop on those degraded hilltops.”

He says farms need something more dramatic than zero tillage, and adding soil to hilltops is an instant and effective measure.

Erosion estimates from University of Manitoba soil specialist David Lobb. Even though the amount of high-eroding cropland was reduced significantly from 1971 to 2011, the 9.5 per cent of high-eroding cropland in 2011 is much more severely eroded after 40 years and the resulting yield loss is much worse, Lobb says. Therefore, 36.8 per cent of the land area suffering a 17 per cent yield loss in 1971 is about the same as 9.5 per cent of the land area suffering a 60 per cent yield loss in 2011. But, he adds, with the overall increase in yields through technological advances and adoption of higher-value crops, the value (in 2016 dollars) of the 2011 loss is higher than in 1971. This is reflected in the bottom two lines, where Lobb compares actual value of the crop versus an estimated value based on potential yields if degraded areas were improved. Note: Low-eroding cropland is classified as having “negligible” to “low” levels of soil erosion. High-eroding cropland has “moderate” to “high” to “very high” levels of soil erosion. This is tracked by province.

To test the benefit, University of Manitoba graduate student Diane Smith ran four trial sites in Manitoba (including one at Timmerman’s farm) in 2008. Smith found that when soil is added back to the hilltops, seedlings emerged faster and more consistently, and plant population was 60 per cent higher than in the control plots. The yield increase was equally encouraging. At the Timmerman trial site, addition of topsoil increased yields by 31 per cent in the first year post-restoration and by 64 per cent the following year. Yield increases for the other sites ranged from 10 to 133 per cent.

Smith also compared yields in the low areas where soil was removed. She concluded that for the most part, removal from the low areas had no effect on yield because these areas generally have more topsoil than needed. One site did show a 20 per cent yield reduction in the lower slope positions where topsoil had been removed, but the net benefit was a 74 per cent increase in crop productivity within the landscape.

In her summary, Smith wrote “Landscape restoration is an innovative, logical, and practical land management practice to restore crop productivity on severely eroded hilltops and requires further attention from researchers and equal consideration from agricultural producers.”

Lobb says soil conservation measures in Western Canada have not improved recently. “Current high-speed vertical tillage tools and high-speed drills move as much soil as a plough ever did.” He notes that while most of that soil stays on the field, its movement reduces crop productivity. What happens is that the A horizon (best) soils erode from the hilltops and are dragged down to the low areas by high-speed soil disturbance. So the low areas get more and more topsoil and the hilltops continue to lose productivity. That sounds bad enough, but as this process continues, the low-productivity B and C horizon soils on the hilltops erode into the depressions, covering up that extra-thick layer of rich topsoil.

Lobb says some of the worst soil erosion in the world has occurred in the “hummocky land of the Prairie pothole region.” The climate is semi-arid, so the hilltop soils don’t have the moisture needed to support crops. And because yields on these hilltops are so low, crops don’t produce enough organic matter to turn the situation around, even with no till.

“We need to redefine or redesign conservation tillage,” he says.

Lobb is surprised by results from an Agriculture and Agri-Food Canada Farm Environmental Management Survey of 2014. In the section on land management practices, the survey found that five per cent of Canadian crop farms were placing eroded soil back on hilltops. That’s higher than Lobb expected, which he finds encouraging, but it’s still a low number. He’d like to see more farmers taking Timmerman’s active approach to hilltop restoration.

What advice does Timmerman have for farmers who might want to train their hills to be more productive? “Get a scraper, and plan to do a small amount each fall,” he says. “It’s more economical to do a little each year on your own than to hire someone to do a lot of acres all at once.”

The UN soils panel

David Lobb is one of two North American soil scientists on the United Nations Intergovernmental Technical Panel on Soil (ITPS). “For most people of the world, healthy soil is an extremely important resource,” Lobb says. “Without productive soil there is a lack of food, and a lack of food brings political instability.”

The safety and security of most countries depends on good soil. “Soil erosion is considered to be the number one threat to soil productivity and health worldwide,” he says. A major focus of this year’s ITPS activities has been controlling soil erosion through sustainable soil management practices.

“Canada is the only country that has a properly validated erosion model combining the effects of wind, water and tillage erosion, and this model is linked to models of soil organic matter and crop productivity and market values, giving us an accurate assessment of the economic impact of soil loss on crop production,” Lobb says. This information greatly supports the need for practices that restore eroded soils. Moving topsoil back to the eroded hilltops is one example.

About the author

Contributor

Jay Whetter is communications manager for the Canola Council of Canada.

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