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Farmers adjust fertility plans after tough fall

There’s still plenty of opportunity to get nitrogen on if you missed the fall application window

While spring banding of fertilizer has become more popular recently, there’s still plenty of growers putting it down in the fall.

That is, unless they run into a season like last year. Many farmers throughout Manitoba struggled to just get the crop off, never mind getting their fall work done.

Now they’re left with the challenge of adjusting practices to apply it this spring. It’s a challenge, but not an insurmountable one, according to Manitoba Agriculture’s John Heard.

“There are a number of options for people who normally put their nitrogen on in the fall,” the soil science specialist told the Co-operator during a recent conversation.

One strategy that will kill two birds with one stone is for the farmers who are facing the reality of rutted fields after a wet fall. They’re likely going to have to do at least some tillage to smooth things out, which presents an opportunity.

“If they’re going to have to do some tillage to fill in the ruts, maybe banding N is part of one of those passes to level things off,” he said. “For some farmers, it’s going to be the reality this spring that they’re doing some amount of tillage.”

That would be the ideal solution, Heard said, because it places the product into the soil where it’s more accessible to the crops, and prevents losses through volatilization into the atmosphere.

“It also reduces immobilization through interaction with crop residue that’s on the surface,” Heard said. “As the bacteria and microbes break down and decompose the residue, they take the N and use it to break down straw. You eventually get it back, but not soon enough for crops like wheat and canola that need N early in the spring.”

Broadcasting

Another well-known option is a surface application either immediately before seeding or just after.

This is a fast way to get N on, with applicators able to get down as much as 1,000 acres in a single day.

Of course there is the potential for loss to the atmosphere until the fertilizer is either incorporated or moved into the soil with precipitation, particularly in the case of granular applications.

“Nitrogen on the surface still needs rainfall to get into the soil,” Heard said. “That’s never a problem in Manitoba… except in 2016, when we didn’t see any rain from April 1 to after the May long weekend at Carman. It doesn’t always rain in Manitoba.”

Timing is also important. For farmers looking to maximize yield potential, applications should be made on the earlier side — before the third-leaf stage or any significant elongation for cereals and prior to significant bolting for canola.

Heard says he expects most farmers will use a combination of methods to get their fertilizer down this season, including more in the seed row. He said most farmers are well aware there’s a tight limit to what can go down without the risk of damage to seed and seedlings. However, there may be a technological element that eases that risk.

“Environmentally safe nitrogen (ESN) allows some flexibility to apply more,” Heard said. “It has a physical coating on it, that helps protect the crop. If they want to do this, and get more in the seed row, that’s an option. It’s built in some flexibility. They can’t meet all the crop’s needs, but it’s a good safe way to place it, and it’s an option we didn’t used to have.”

Banding

Many producers have already made the investment in side-banding equipment that allows them to place nitrogen beside and below the seed.

These include simple systems where liquid nitrogen is dispensed through a tube on the seed opener and mixed with the soil as it falls back into place over the seed, boots that apply fertilizer in a separate band and systems with a completely separate boot for fertilizer applications at the mid-row.

“For the people who have this equipment, spring applications were always Plan A, and they’ll continue on with that,” Heard said.

For producers considering taking the plunge now that they’re forced into shifting their applications, there are a few wrinkles that should be taken into account.

First and foremost, a 1×1-inch separation between seed and fertilizer might not be large enough to ensure crop safety under Manitoba conditions.

Mid-row banding between every second row at seeding demonstrates the most reliable crop safety. Disc-type mid-row banders can achieve it with less soil disturbance and greater moisture retention, compared to knife type.

Liquid fertilizers are easier to work with than granular or ammonia applications because the equipment used to apply them is often easier to work with and simpler to modify.

Anhydrous can be safely applied with side-banding and mid-row-banding equipment, so long as separation from the seed is maintained, and is a relatively low-cost source of nitrogen. One issue to watch for, however, is the risk that the gas travels through soil pores and fractures to the seed, where it can cause damage.

A new tactic that’s starting to gain currency among innovative producers is banding nitrogen immediately following seeding. Years back researchers did this on a plot scale and got good results, but only lately has the technology caught up to the strategy, Heard said.

“An increasing number of innovators are actually running coulter units into established cereal crops and putting down N when the crop is up because of the availability of good guidance systems,” Heard said. “It’s kind of like what they do with corn and is very interesting.”

Heard noted both the late Guy Lafond of the Indian Head Research Farm and Byron Irvine of the Brandon Research Centre looked at this 10 or 15 years ago, with good results. But they flagged some technical challenges.

“Now we’ve arrived,” Heard said. “The technology is at the stage that innovative farmers are doing it.”

For more information on this topic, check out a fact sheet on spring fertility co-authored by Heard and University of Manitoba soil science professor, Don Flaten that’s online at the Canola Council of Canada’s CanolaWatch Website.

About the author

Editor

Gord Gilmour is Editor of the Manitoba Co-operator.

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