Nitrogen placement trials show side-band N cuts canola emergence without lowering yield
Placing nitrogen in the side band is often seen as a risky move for canola, but research suggests yield may not be what’s at risk.
Curtis De Gooijer, in-house agronomist with Bourgault, said side-by-side trials show nitrogen placement can significantly reduce canola plant stands without consistently affecting yield.
He shared the findings during a presentation at Ag Days in Brandon in January earlier this winter.
Read Also
Niche crops making their mark in southern Alberta
Handful of specialty crop growers speak of their passions and challenges growing their crops that are not as common in southern Alberta
Why it Matters: Understanding how nitrogen placement affects plant stand can help growers manage risk and protect crop resilience.
The trials compared dual knife systems with nitrogen placed in the mid-row band (MRB) or in the side band (SB). Over nine years, yields were statistically similar. Nitrogen in the mid-row band averaged 55.2 bushels per acre, while nitrogen in the side band averaged 54.5 bu. per acre.
From a straight yield standpoint, there was no meaningful separation between the two systems. Plant stand, however, told a different story.
Yield similar, stand different
Across the nine-year average, the mid-row band system averaged 6.1 plants per sq. foot. The side band system averaged 4.6 plants per sq. foot.
When higher nitrogen rates were brought closer to the seed, stand reductions became more pronounced.
At 140 pounds actual nitrogen, canola emergence averaged about 17 per cent lower when nitrogen was placed tight in the side band. The effect was much less consistent in wheat, but in canola it showed up reliably.
A 2020 comparison illustrated the difference clearly.
In a year with strong early growth that later turned dry, the mid-row band treatment established 8.6 plants per sq. foot. The side-band placement established 4.9 plants per sq. foot.
“That was a significant decrease in plant stand,” De Gooijer said.
Bigger plants don’t mean better access
The visual effect can be misleading. In some cases, the thinner stands produced larger individual plants. Observers sometimes assume those plants had better access to nitrogen.
But the larger size was a function of reduced competition.
“The crop was responding to plant stand, not necessarily to better nitrogen access,” he said.
With fewer neighbours competing for light, moisture and nutrients, the remaining plants branched more aggressively. Lower plant stands tended to produce larger plants and, in some cases, longer maturity.
Once stand is set, yield becomes increasingly dependent on seasonal conditions.
“You can still get good yield with lower plant stands,” De Gooijer said.
Nitrogen placement first influences plant mortality and final stand. Stand then influences plant size and maturity. From there, weather during flowering and grain fill plays a larger role in determining final yield.
Small shifts, measurable effects
The work also showed that small adjustments in placement distance can help protect stand without sacrificing yield.
In a dual shank side-band system, standard placement was roughly 1.5 inches to the side and one inch below the seed. Moving nitrogen to two inches and then 2.5 inches from the seed incrementally improved plant stand.
“It doesn’t take much distance to improve emergence,” De Gooijer said.
Despite those changes in stand, yields over the past several years remained statistically similar between placements.
The takeaway is not that nitrogen placement is irrelevant, but that it primarily works through its effect on plant stand. Those thinner stands were often able to compensate, producing comparable yields under the right conditions. But in years with additional stress, that reduced stand may offer less resilience.
“Lower plant stand means bigger plants in general,” said De Gooijer.
“After that, yield becomes year- and weather-dependent.”
Source: producer.com