Strip tillage and cover crops are two techniques being tested in southern Alberta applied research trials, seeking practices that will help reduce the risk of soil erosion.
Farmers on the Prairies — and across North America — have made huge strides over the past 40 years in reducing soil losses by applying conservation farming practices such as continuous cropping along with zero and minimum tillage and direct seeding.
However, when growing row crops such as corn, potatoes, sugar beets, seed canola and, in some areas, even commodity canola, tillage is still needed to manage crop residue and prepare seed beds — and those two or sometimes three tillage operations can leave soil exposed. Then any strong winds blasting across the Prairies, especially in early spring just before or as crops are emerging, can result in blowing soil and crop damage.
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Southern Alberta winds, which some days can range from 50 to 100 km/h, may blow shallow-seeded seed out of the soil — and on the fly, that soil can sandblast exposed plant seedlings, often requiring acres to be reseeded. Hilltops are particularly vulnerable.
So how do you get row crops seeded while still reducing the risk of soil erosion?
The applied research group, Farming Smarter, has a number of trials looking at the role of strip tillage as well as cover crops in protecting the soil, says Lewis Baarda, manager of field scale research trials.
More western Canadian farmers are becoming aware of strip tillage, which was developed in U.S. corn and soybean growing regions about 35 years ago.
Strip tillage takes a specially designed tillage tool that works up the soil in a strip where a crop row will be planted. While a vacuum planter is an excellent tool for seeding many row crops, it is not particularly well adapted to working through crop residue, so some degree of tillage to manage residue is needed.
From among the different designs of strip tillage machines, Farming Smarter is working with a unit that on each row has a coulter up front to cut through crop residue, followed by a row cleaner to move residue, followed by a shank opener than can be adjusted to run at various depths to loosen the seed bed and often used to place fertilizer in the seed row. A packer wheel or rolling basket, to further condition the soil, are optional features on strip tillage machines.
Baarda started with a strip tillage trial in small research plots in 2023 and this year is working with a field-scale trial.
“We are working with a producer north of Lethbridge, for example, who is seeding crops with a vacuum planter on 22-inch row spacing,” he says.
The strip tillage machine is also set on 22-inch spacing. It works up the soil disturbing about a 10-inch-wide strip of soil, leaving a 12-inch strip of undisturbed soil between the tillage rows.
“The value is that with the strip tillage tool you are only exposing between 30 and 40 per cent of the field to the risk of soil erosion, rather than 100 per cent,” he says.
In the 2024 on-farm research trial, the producer first made a pass over a 160-acre field with a strip tillage tool, at the same time placing fertilizer below the seed row. About 10 days later he came back with the vacuum planter and seeded commodity canola. This research trial will be monitored through to harvest, to see how well the crop performed.
How it’s going
Did the strip tillage treatment reduce the risk of soil erosion and crop damage? “It is only an anecdotal experience, but I believe it did make a difference,” Baarda says. “I travelled to the research trial this spring after the crop was seeded, and on that day the wind was blowing and there was a lot of soil blowing off nearby fields that were conventionally farmed and seeded, but no sign of any soil moving off the field that was strip-tilled. It wasn’t a scientific measurement, but it appeared that something made the difference.”
Baarda says from the 2023 small plot research trials, he compared a crop grown on strip tillage with other plots seeded by direct seeding, as well as conventional or full tillage.
“The results showed there really wasn’t much difference between the three treatments in terms of crop performance and yield,” he says, noting that in small plots, it’s difficult to observe whether any soil erosion occurred.
“That small research trial showed us there was really no disadvantage in using the strip tillage tool, so on a field scale level, if strip tillage helps to reduce the risk of soil erosion, that in itself is a benefit.”
Finding the cover crop fit
In other research projects, Baarda wants to see whether cover crops can be used to protect the soil after row crops have been harvested. Cereal crops and corn, for example, leave behind stubble and stalks after harvest which help protect the soil, while with row crops such as dry beans, sugar beets and potatoes, there isn’t much ground cover left once beans and root crops are harvested.
“They are what we describe as high-disturbance special crops,” he says. “And the big challenge in terms of cover crops is that potatoes and sugar beets are harvested later in the season. It doesn’t leave much time to get a cover crop established. Potatoes often come off in September, but sugar beets usually aren’t harvested until October.
“Some years we are lucky and there is no frost until quite late, but it’s not something we can count on.”
Among the options he says he hopes to try, with potatoes and sugar beets in particular, is to direct-seed or broadcast-apply either a cereal crop seed, such as barley, or winter peas or camelina, on potatoes and sugar beets during the growing season, to catch and hopefully hang in to provide a cover crop once the crop is removed.
“We did try using a planter to seed winter wheat and barley in sugar beets in June, but it might have been too late,” Baarda says. “We will try interseeding a cover crop a bit earlier. The cover crop may compete with the sugar beets a bit, but that is something we’ll have to evaluate.”
With dry beans usually harvested in August, there’s more of a window to get a cover crop growing. He says it may work to use a box seeder to plant barley in a bean field before the crop is combined, but with any field operations made before the beans are combined comes the need to protect crop quality.
“I have also heard of using drones to seed a cover crop, and that may be something to consider as well,” Baarda says. “Our objective is to try different types of cover crops at different times to see what might work the best and hopefully provide farmers some options to reduce the risk of soil erosion.”
ALSO: Erosion may be more about soil quality than wind
With increasingly volatile weather around the world being blamed on the effects of climate change, are the prevailing chinook winds across southern Alberta and the rest of the Prairies getting stronger or more intense?
While a couple of years ago there was a record-setting gust of wind as high as 204 km/h at Pincher Creek in southern Alberta, longer-term weather data shows overall that wind intensity across Western Canada has changed very little over the past 40 years.
Colorado-based weather specialist Matt Makens says the winds across Western Canada can certainly be variable from year to year, but overall fall within historical averages.
“I looked into the wind from this May/June to see how it related to the long-term normal and found this year was windier than normal across parts of Western Canada,” says Makens, an atmospheric scientist and owner of weather consulting service Makens Weather.
A timeline of winds for a portion of Alberta “shows there are some peaks and valleys with May/June winds since 1980, but the overall trend is nearly flat for the period. The actual growth of wind from year to year is 0.00055 metres per second, which is hardly anything and not really detectable.”
While it appears wind intensity isn’t necessarily stronger, he suggests longer periods of drought may be affecting soil quality and risk of erosion.
“I think one factor to consider with soil erosion in the past decade is the types/durations of drought we have been in,” he says. “Consider the 2021-2023 period of drought in Alberta, which was worse and longer than any other since 2002.
“The soils in this period were rough, making it easier to have soil losses regardless of whether the wind was stronger. To me, the bigger factor now in erosion is less about wind (since there’s little change in decades) and more about soil health, which has been notably degraded in recent years.”
