WEYBURN, Sask. – Canola responded best to nitrogen fertilizer among four oilseeds at four different Saskatchewan locations, according to a three-year study.
But that doesn’t mean applying more nitrogen is better, especially during these times of high fertilizer prices.
Research agronomist Bill May told farmers attending the Indian Head Agricultural Research Foundation winter seminar here that they need to know how responsive their fields are to give them the best idea of how much nitrogen to use.
He said farmers should be cautious about the amount they apply.
Read Also
VIDEO: Green Lightning and Nytro Ag win sustainability innovation award
Nytro Ag Corp and Green Lightning recieved an innovation award at Ag in Motion 2025 for the Green Lightning Nitrogen Machine, which converts atmospheric nitrogen into a plant-usable form.
“The seat-of-the-pants economic analysis we’ve done shows that for the average yield curve for canola, there’s a wide range of nitrogen rates you can use that give you the same amount of money after you’ve paid for your nitrogen fertilizer,” he said in an interview.
The study was done at plots around Saskatchewan at Indian Head, Swift Current, Scott, Melfort and Redvers during the 2004, 2005 and 2006 growing seasons. The Scott data was left out of the final analysis because two years of data were lost.
Researchers compared the nitrogen response of sunflower and brassica juncea to that of canola and flax. The idea was that farmers might be looking to increase production of sunflowers and juncea.
May said the sunflowers only did well at the Swift Current site, likely because the available cultivars aren’t the most adapted. New hybrids reflecting a different oil type aren’t bred for Saskatchewan.
“We’ve lost varieties like Pioneer 6150,” he said.
“We haven’t found any short, early-maturing sunflowers that really do as well as 6150 did.”
The brassica juncea results showed its responses were similar to flax and canola, but with lower yield potential. May said that is also due to a lack of cultivars.
“If you’re going to be growing a juncea, you’re better off growing a non-canola one than competing against canola,” he said.
The study looked at average gross returns of the crops in response to changes in the nitrogen rate and at different crop prices.
The return for sunflowers and juncea canola was similar from applications of nine to 62 pounds per acre when crop prices are low and nitrogen costs are high, May said. At higher rates, the returns declined.
“The adjusted gross return for sunflower indicated that there was no advantage to increasing N rate as the sunflower price increased and fertilizer cost decreased,” May wrote in his report.
“A small increase in the adjusted gross return of juncea canola could be captured by increasing the N rate to 90 kg per ha (79 lb. per acre) as the crop price increased and fertilizer cost decreased.”
Returns for flax didn’t increase when more than 44 lb. per acre of nitrogen was applied, crop prices were low and fertilizer prices high. The adjusted gross return for flax was optimized at a nitrogen rate of 79 lb. per acre.
But the returns for canola were similar across a wide range of nitrogen rates when crop prices were low. As canola prices rose, the adjusted gross return was maximized at 97 lb. per acre.
May said a full economic analysis of the data still has to be carried out. Producers have to determine how much risk they can take and they can do that by knowing how responsive their fields are.
“The more confident you are that your curve is more responsive, the more risk you can take,” he said.
There are benefits to being conservative with nitrogen rates even at high prices, he noted. If urea prices jump to $1,000 per tonne and crop prices stay where they are, producers could cut back and still do well.
May added that fertilizer retailers should make sure producers use appropriate amounts of nitrogen.
“It’s in the best interests of the retailers because then their customers are economically better off and they’ll be there next year to buy fertilizer from them.”
The study also found nitrogen had no effect on oil content. It did boost protein, which is good for canola meal, but that doesn’t pay growers any more money.
