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A new era of agronomics and genetics for corn

The “how” and the “why” of growing corn are attracting a lot of fresh thinking

Corn production has risen to a new level of importance, both for growers and for the industry that supports them. In spite of market pressures and uncertainty in global trade, growers, particularly those in Ontario, are firmly committed to planting row after row of the crop, basically as much as they can.

Yet the reality is that if corn has become more of a mainline crop on many farms, it’s mostly the crop’s consistency and predictability that has done it, coupled with its impressive and steadily increasing yield performance.

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There’s no single factor to thank. Instead, it has all come together for corn, including trait development and enhancement, advances in precision agriculture systems and their adoption, improved fertility, and adoption and investment in on-farm drying and storage systems. Each pillar has gained ground in the past 10 years. Many crop watchers would say even more so in the last five.

When the term “trait” is mentioned in reference to corn production, it’s often an allusion to Bt technology or to the glyphosate resistance or insect tolerance carried by most hybrids. Yet just as seed companies involved in the wheat sector have done a solid job of screening out varieties susceptible to fusarium head blight, the corn sector has done the same with monitoring desired and undesired characteristics in hybrids.

Beyond insect tolerance or herbicide resistance, plant breeders and researchers have been investigating so-called “native traits” such as drought tolerance or reduced susceptibility to anthracnose. There may not be as targeted an effort here as on the transgenic traits, but the results are no less significant for the crop’s long-term production scenarios.

“This research is providing a hardier corn plant that can withstand environmental stress,” says Stephen Denys, brand director with Maizex Seeds. “Most farmers will say that one of the reasons for success in corn today is the genetics available and the stresses these hybrids can take through the season in this age of environmental instability, compared to what they would have planted even 20 years ago.”

Corn about to tassel.
photo: Courtesy of Wayne Black, Sunderland Co-op

But over and above the plant itself, Denys makes an interesting case that corn’s evolution has come with support from the entire industry, including equipment and systems manufacturers as well as precision ag developers and dealers. He cites the trend of strip till becoming more of a mainstream practice compared to the turn of the century and notes more growers are doing their own on-farm research on optimizing nitrogen rates and timing.

“We’re also seeing a definitive increase for early- and mid-adopters utilizing data collected through the year — from planting to harvest, including tissue analysis —tied to variable-rate population and fertilizer,” says Denys. He adds that particular facet is developing to optimize yields and input costs. “The other trend would be fine-tuning fertility programs from a second-tier macronutrient and micronutrient perspective, including increased use of sulphur, and trials and use of nutrients such as boron.”

Nutrient response and planting dates are two other intriguing trends which Denys notes are changing perceptions at the grower level. The term “stress tolerance” is often confused with nutrient response, yet different hybrids react differently to intensive management practices, hence the commitment by seed companies to test every hybrid on a multi-year basis. The goal is to determine the responses to intensive management practices, including plant populations, fungicide treatments or nitrogen rate response.

“This allows us to better match hybrids to specific production conditions,” adds Denys, who also farms in Chatham-Kent. “Some hybrids do respond to overall N rates while others do not benefit to the same degree, so knowing your soil type and understanding the inherent yield potential across your fields can aid in hybrid selection.”

As for planting dates, again, it’s research into native stress tolerances in available genetics that has allowed growers to push their planting dates earlier. There’s a growing recognition of the importance of planting when the ground is fit, and it’s been reflected in observations from this past spring, including side-by-side fields with visible variability. In those cases, says Denys, it might relate back to decisions made at planting, like whether the field was planted before or after a cool night or a three-inch rain. Or what was the fall tillage treatment in one field compared to another?

“These are the questions we need to ask ourselves and review as we begin planning for 2021,” says Denys. “Patience has always paid in farming, and that’s even more the case where we have big equipment that can go through anything or tractors with really comfortable cabs that can give us a false sense of security about how fit the ground is for planting. The most important tillage tool I own is my shovel and it’s the first implement used on every field.”

Farther afield

Those lessons learned are occurring across a larger geographic region and growers and advisors alike are pushing their management skills as a result. Yet there is a long way to go with each aspect, says Wayne Black, agronomy sales manager with Sunderland Co-operative.

“Are we covering more acres with more advanced knowledge of our fertility programs? Yes,” he says. “Are we covering more acres with the latest genetics and traits in corn hybrids? Yes we are. Are we covering more acres with fungicides and pesticides than in the past? Yes we are.”

But is that across the board? Are all farmers managing more of their fields for higher profitability? Black knows of some farms that become more productive and profitable, thanks in large part to improved hybrids and a greater commitment by growers to a higher level of management. But is that always the case?

“There are more tools available to do the late-season nitrogen application or to properly measure the use of the pre-sidedress nitrogen test (PSNT) or SoilScan from the 360 Yield Center,” explains Black. “There are tools that can determine how much nutrient you need and better knowledge available on the timing for an uptake of nutrients for the corn plant. And every year, we’re seeing a slight increase in the number of acres we cover with that late-season nitrogen application.”

Size may matter but so does depth: corn on the right was planted at one-inch depth, corn on the left was planted at two-inch depth. The target should be 1.75 inches.
photo: Courtesy of Wayne Black, Sunderland Co-op

However, he questions whether growers could be better stewards of their corn ground, a reference to the job done with the 4R Stewardship initiative. Conservation authorities and other environmental agencies have done a good job of highlighting Great Lakes pollution and specifically, the algal blooms in Lake Erie. But if growers are relying solely on genetic tweaking in hybrids or advanced equipment technologies on their own, they may be missing the full extent of every opportunity.

“We need to dig deeper into the details of what we can collect today, whether that’s imagery data or through predictive modelling, but we also need that data on hybrid capabilities,” Black says. “We need more information such as on the seed germination percentage in the bag, along with warm germination and cold germination. If we’re going to be content with 110-, 160- or 210-bushel corn, we’re not going to change.”

It’s not that he wants to focus more on the negatives, but Black cites the research data and information that have come out of the last 20 years, and he cautions that some of the recommendations tend to blur. For instance, research shows that traits introduced since 1995 respond more to late-season nitrogen applications because agronomists learned today’s corn plants take up 75 per cent of their nitrogen needs at tasselling and beyond. Previously, hybrids only took up 60 per cent at that point.

“There’s a thought process that the newer genetics have changed nutrient uptake, but I question whether it’s the genetics that have changed how the crop takes up those nutrients,” says Black. “Or is it that newer, high-yielding hybrids are taking up nutrients at different stages or different ratios at each stage because it’s going more to kernel production than to the stalk or leaf?”

Whether it’s the genetic capabilities of the hybrids or understanding the needs and timing to produce higher-yielding corn, growers can’t use the same starter program they did in 1990. Not only do they need to rethink their fertilizer program, they need to reconsider the timing.

“It goes back to those growers who are using the proper fertility programs,” says Black. “They’re profitable, they’re expanding their acres or switching to others if they’re renting. They’re maximizing their profitability per acre. That goes hand-in-hand with positioning the right hybrid, which goes back to the better managers who will include their agronomist, their equipment sales rep, their seed or chemical dealer and fertilizer dealer. All of them will be involved in that conversation to maximize profitability.”

Future still looks bright

Although the learning curve continues upward, Denys believes there are still greater heights to be achieved with advances in genetics and agronomic practices. Planting when the ground is fit, minimizing weeds during the critical weed-free period, and timely use of fungicides continue to be fundamentals. However, he sees breeding programs geared to Western Canada corn production benefiting growers in Eastern Canada, as well. In creating hybrids for early maturity areas in the West, Eastern production will benefit from more stress-tolerant genetics that are helping growers cope with environmental stresses and increased severity in those stresses.

“What’s interesting is the genetic potential across maturity ranges,” adds Denys, citing the importance of improved genetics in raising provincial yield averages. “We had farmers in many parts of Ontario and Quebec who had to switch to early-maturity hybrids given the wet start in 2019. Overall, the earlier-maturing hybrids provided an excellent crop not far out of line with their original expectations.”

The same thing has happened in Manitoba, where trials in the last few years have produced yield levels in many locations that can rival those in southwestern Ontario.

“I expect that as we go forward, we’ll see further research into inherent natural trait selection for stress tolerance,” says Denys. “Plus a movement that looks at corn height for grain corn, as an example, and continued research on silage hybrids to optimize tonnage and quality.”

This article originally published in the September 2020 issue of the Corn Guide.

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CG Production Editor

Ralph Pearce

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