In a dry year like this one, investing in foliar fertilizer probably won’t pay off.
“Conditions at the time of spraying are the trump card,” said agronomist Jack Payne at canolaPALOOZA in late June.
“Herbicides are also absorbed through the foliage, but if the plant’s not actively growing — if it’s shutting down because of drought stress or heat stress — your herbicides typically don’t work.”
The same is true for foliar fertilizers, he said.
“If the plant is shutting down, it’s not going to be that efficient.”
In research test plots in Lacombe, there’s “not a lot of difference” between the plants that were treated with foliar micronutrients and those that weren’t, said Warren Ward, an agronomist with the Canola Council of Canada.
“On this beautiful soil we have in Lacombe, we’re not seeing a whole lot of difference,” said Ward. “Because it’s so nice, you don’t see a whole lot of response from fertility here.”
At this stage, the treated plants are actually slightly delayed in maturity because the applied product set the plants back slightly, he said. But the weather plays a role as well.
“This year, some of the areas with deficient moisture scenarios could be showing different results as well,” said Ward.
“If you look at how a plant’s designed to take up nutrients, it’s through the roots, not so much through the leaves. It’s a much more efficient way of getting what the plant needs into the plant.”
And in dry conditions, “the cuticle on the leaves will start to get thicker,” making it more difficult for micronutrients to absorb into the plant, said Payne.
“The waxy cuticle keeps water in, but it also keeps things out,” he said.
“If the plant starts going into drought, it could happen.”
Regardless of the weather, producers need to “establish the need for micronutrients before they spray,” said agronomist Rigas Karamanos.
“It doesn’t matter what the weather is — if you don’t need it, you shouldn’t be spraying in the first place,” said Karamanos, adding that soil tests can help producers determine if there is a need for micronutrients.
Much of the hype around micronutrients is done for “marketing purposes,” he said.
“I’ve done a lot of research with micronutrients, and the only one of serious concern in Western Canada is copper.”
Producers should base their purchasing decisions on cold, hard numbers — not how the crop looks, said Payne.
“You’re growing the crop for bushels in the bin,” he said. “You might see something that looks marginally visual right now and say, ‘That looks bad.’ Well, looks don’t pay the bills. Does it translate to yield? That’s what it always goes back to.”