How to break through the winter wheat yield ceiling

It takes a balanced fertility approach

Winter wheat yields in Manitoba over the past few years have been in the 60 to 70 bushel per acre range, but many varieties have a much higher yield potential — more than 100 bu/ac. What can western Canadian farmers do to break through that yield ceiling?

Ducks Unlimited Canada (DUC) has a long association with winter wheat producers. The group has been working with a number of farmers who are trying a balanced fertility approach, which is helping them achieve higher winter wheat yields.

Conventional fertility recommendations for winter wheat are to apply around 100 pounds of nitrogen (N) per acre and 30 pounds of phosphorus (P) per acre in the fall. When DUC experimented with bumping the N level up, there wasn’t a significant increase in yield. This led to the development of a more balanced fertility approach.

Over the last two years, DUC has been working with Western Ag, using its balanced nutrition model based on the company’s proprietary soil tests, which applies split rates (half at seeding and half later in the spring) of N, P and K (potassium).

In 2019, these trials were carried out in farmers’ fields. Winter wheat yields averaged 80 bu/ac with the balanced nutrition system in those field-scale trials. The provincial average winter wheat yield in 2019 was 58 bu/ac. Every variety in the trial had a yield boost.

At the Manitoba Agronomists’ Conference in Winnipeg last December, Ken Gross of Ducks Unlimited Canada presented results from field-scale farmer trials using a balanced fertility approach to winter wheat. Some producers had above-average yields in 2019 and offered tips on how to break through the winter wheat yield ceiling. photo: Ducks Unlimited Canada

“That was partly due to the fact that we saw more green in these fields all through the year and extending into the fall,” said Ken Gross of Ducks Unlimited Canada during his presentation at the Manitoba Agronomists’ Conference last December. In wheat, the leaves contribute 57 per cent of the yield (versus the stalk or ear), so keeping the flag leaf green and functional during the filling period is important for higher yield, he added. “If you want to press through that yield ceiling, you have to focus on balanced fertility.”

Practical experience

Doug Martin, a long-time winter wheat grower from Selkirk, Man., is one of the producers who has been trying the balanced nutrition approach. In the past, Martin would generally add a little P and some N at seeding. With the balanced approach he also added some potash, N and a higher rate of P based on soil test results.

Doug Martin. photo: Supplied

“We haven’t really used a lot of potash in the past on our cereals, so we added it as part of our start-up fertility,” he says.

Unfortunately, the dry conditions in the region over the past three years have affected fertilizer applications and yield, so the jury is still out on the benefits of this balanced nutrition approach on his farm. For example, the recommendation was to mid-row band the fertility at seeding, but Martin decided to broadcast it just prior to the first snowfall because he didn’t want to disturb the stubble, which is important to get the crop through the winter and to catch as much moisture as possible.

“It seems to me that winter wheat needs a good shot of rain early in the growing season, or it can (negatively) affect the yield,” Martin says. It’s why last fall, he also decided against a split application of N, instead applying most of his fertility in the fall in anticipation that spring this year could again be dry.

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Last year, because he had some winterkill and very little moisture, yields were not that great, but this year he has soil moisture sensors in place, which should help him decide whether to top up his fertility in crop.

“If I want to put more fertility on, it gives you an idea of whether there is adequate moisture in the ground (to make it worthwhile), so it helps you make that decision,” he says.

Although there has been no economic analysis of the balanced fertility approach to date, Gross said some of the producers involved in the field-scale study, who were locked into contracts at $7 per bushel with Parrish & Heimbecker for the last two growing seasons, were very happy with the results.

Fall nitrogen application

Gross also emphasized a good practice for winter wheat growers in Manitoba, and other Prairie provinces, is to get some N down in the fall.

“The winter wheat plant doesn’t produce a seed head until the spring, and it needs to have the fertility there very early on in the spring when it starts to regrow,” Gross said. “If you don’t have the fertility there when the plant begins to produce a seed head, it won’t be a big, healthy seed head.”

In Manitoba, it’s often difficult for producers to get their fertility on early in the spring because it’s often too wet to get into the field. The plant starts growing and by the time farmers can apply their fertility, it’s too late. Or, when conditions are dry in the spring, as was the case in 2020, even when they can get on the field early, farmers are broadcasting fertilizer, and if there is a delay before rain comes to get it into the ground, it can also be too late to have a positive effect on yield.

“Most of our producers are trying to get at least half of their fertility down in the fall, and we’ve seen a big difference with that,” Gross said.

Trevor Woychyshyn, who farms near Rossburn, hasn’t always applied N on his winter wheat in the fall, but since he started using ESN (a slow-release, polymer-coated urea), he finds it easier and more effective to side-band all the N at seeding.

“What we like is it’s one less thing to do in the spring, and that was one of the reasons we started growing winter wheat in the first place, to save time in the spring and get a kick-start on harvest,” Woychyshyn says.

“I think the (introduction of ESN) may be why the practice (of applying N to winter wheat in the fall) is a bit more common. Prior to that, it was too risky to apply all that N in the fall due to potential losses, and also not wanting that N to activate in the soil until the following spring. ESN is placed in the soil, so it’s in soil moisture and it’s (less dependent on precipitation in the spring).”

One of the biggest concerns about applying N on winter crops is winterkill, however, it’s not going to be wasted. “If our winter wheat doesn’t survive, we would be putting in a different crop like canola or wheat, so all the applied N is still there and is going to be used,” says Woychyshyn.

About the author

Contributor

Angela Lovell

Angela Lovell is a freelance writer based in Manitou, Manitoba. Visit her website at http://alovell.ca or follow her on Twitter @angelalovell10.

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