The Population Grail

July 27, 2012 09:25 PM
The Population Grail

A look at the value and risk of increasing populations

The need to push corn plant populations is manifest destiny. Increasing profits by using the best hybrid seed is the motivation, but it’s also a response to paying progressive increases in input costs. That means either farming more acres or seeding more plants per acre (ppa) and knowing the break-even point so inputs are maximized.
Runaway yield results and profitability are not guaranteed, because not all hybrids are created equal, high-dollar corn is probably not sustainable and weather doesn’t always cooperate on fields of varying soil fertility. Still, that doesn’t mean Corn Belt farmers are shy when it comes to going for the gold.

Push the limits. Corn Belt university research shows that yield increases over the past 60 years have not come from larger ears on individual plants, but from more plants per acre. Given this, the thought of planting corn 12" apart in 12"-rows is kind of mind-boggling, but that may be where we’re headed, according to David Thompson of Stine Seed Company.
The research, which focuses on equidistant spacing, involves 43,560 plants of dryland corn per acre on 3,500 acres near Adel, Iowa, just west of Des Moines.
"As a seed company, we need to be looking at the yield trend over the last 80 years and asking ourselves, ‘Is it going to stop? Probably not,’ " Thompson says. With trait-loaded hybrid corn seed priced at a premium $280 to $300 per bag, which is roughly $150 per acre, it becomes imperative to absorb the cost by producing higher yields.
"We’re not really increasing populations enough to make price an issue," says Brian Hora, a corn and soybean farmer from Washington, Iowa. Starting five years ago with a twin-row planter on 30" centers, Hora pushed his corn population up to 38,000 ppa. As for a control population base, "most of the corn in this area is planted between 32,000 and 36,000," he says.
Hora has pushed plants per acre up to 40,000 but says the hybrids tested at this level don’t seem to be able to increase the yield.
"Every year there seems to be some corn that responds to the heavier populations and with some others, we’ve had problems. We’re trying to figure out which hybrid works best in that situation—not just for yield, but standability as well," Hora says.
If the commodity price for corn should drop to $4 per bushel with no resulting drop in seed cost, Hora says, it will be even more important to maximize yield.

Price in perspective. "We’re seeing more interest from our customers in planting higher populations," says Matt Foes, regional agronomist with Monsanto in northern Illinois.
Putting price in perspective, he says that high-quality, high-potential seed is something everybody always wants to get at a lower price, but they see the value in premium seed. Foes emphasizes the importance of field testing the newest hybrids every year. "A seed company has three to five top hybrids, and you can bet that one or two of those will change every year," he says.
Corn, soybean and dairy farmer Jeff Heinsohn has pushed his number of corn plants per acre using a 20" row planter that does double-duty with soybeans. His Kirkland, Ill., farm in the northern part of the state has a variety of soils, from sandy loam to black dirt. He takes advantage of input cost savings by investing in variable-rate technology with planting rates that have run between 28,000 to 42,000 ppa, depending on the soil type.
"I think this is the future, but to be honest, we pulled back some last year from 42,000," Heinsohn says. "We had more tip pullback than we would have liked on the better ground."
Another hybrid might be needed, he adds, but nitrogen applications matched with the right hybrid may play a bigger role in achieving the 40,000 ppa goal.
"We’re experimenting with a fall application rate followed up with two sidedress applications—one around V5 and another around V10," Heinsohn says. "Until we get this figured out, the risk of planting 40,000-plus plants per acre is a little more than the reward. I’m just worried about asking the right questions at this point—we’ll worry about the answers later."

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