Wheat School: New Nitrogen Strategies Needed to Keep Up With Big Yield Potential

Don Flaten leads a tour of one of the on-farm research sites for updating nitrogen strategies for higher yielding wheat varieties.

It’s been a long time since the last public research was conducted to support nitrogen fertilizer recommendations for wheat on the eastern side of the prairies.

“The last time we did publicly-funded research on wheat yields and nitrogen fertilizer recommendations was actually about 45 years ago, so we were dealing with lower yielding wheat varieties at that time,” notes Don Flaten, soil scientist at the University of Manitoba, in this Wheat School episode.

With farmers growing new varieties capable of yielding more than 100 bushels an acre, the Manitoba Wheat and Barley Growers Association is funding a two-year research project looking at optimum nitrogen fertilizer management for higher spring wheat yields.

Building on preliminary work led by Manitoba Agriculture’s John Heard in 2015, a more intensive research project was initiated this year, involving on-farm tests across Manitoba, as well as treatment comparisons at government and university research facilities.

Flaten says he expects the research will support changing what’s currently on the books for N application in wheat.

“Our past recommendations only carry us up to a yield potential of 50 bushels to the acre with Neepawa spring wheat. So whatever we develop from this will be better than what we’ve had historically,” he says.

2.5 lbs of N per bushel of wheat yield has traditionally been used as a rule-of-thumb for wheat production on the prairies. Extrapolating for a 100 bu/ac yield, that’s a whopping 250 lb/ac nitrogen requirement.

“That’s a huge amount of nitrogen to put on all at once. It’s a huge amount of nitrogen to put on at anytime,” notes Flaten. “The agronomic risk of having lodging and disease means we have to look at having alternative strategies in managing our nitrogen — mid-season, maybe some controlled release products, maybe some different rates for these different varieties as well.”

So they’re not only looking at nitrogen rates, but a combination of application timing, different forms of nitrogen and enhanced efficiency products, fertilizer placement, and differences between varieties. Mid-season N applications were made at stem elongation and heading, as well as post-anthesis to boost protein.

Flaten says they’ll be sharing interim results this winter, with another year of data collection planned for 2017.

“It’ll be another year and half from now before we have something that I’d regard as more reliable or definite.”

Related: Wheat School: Updating N Recommendations for Higher Yielding Wheat

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