When you consider corn yield potential, it’s at its highest when it’s coming out of the bag and going into the ground, says Erick Larson, Mississippi State University Extension small grains agronomist.

“The difference between corn and other crops is that corn has much less compensation ability than some of the other row crops,” said Larson at the recent Alabama Corn/Wheat Short Course in Shorter. “Corn is a crop where you put a seed in the ground and get one plant that produces one stalk, and one piece of fruit on that plant and one ear generally. It does have the physiological ability to put out more than that, but you’re never going to be in a situation where you’re optimizing yield relying solely on the plant.”

That makes it all the more important to get a good stand, he says.

“There are some management strategies you can perform during the season – certainly irrigation is becoming more important, even in dryland areas – but we need to start out with as much yield potential as we possibly can,” says Larson.

The ideal situation is for all plants to come up at the same time and be spaced as evenly as possible, he says.

“One of the things we’ve looked at over the last several years in our research is methods to improve planter performance. We’ve looked at planter ground speed and the effect that may have on uniformity, along with the seed metering system.”

Larson has tested a standard John Deere planter with a 30-seed cell metering system as well as the same planter outfitted with an eSet-type metering system for precision planting. “We measured the plant spacing variability between all plants in the treatment and came up with a representation of how uniform it is.

“Increasing planter speed from 3 to 4 to 5 to 6 miles per hour, the amount of variability in planting increased with each increase in miles-per-hour. Stands are definitely more uniform at the lower speeds, but the eSet overall produced more uniform plant spacing than the standard John Deere unit.”

The yield results were inverse from the plant-spacing results, he says. The yields for the standard John Deere system fell off slightly more than with the after-market metering system, and the average yields for the after-market metering system were at a higher level than the standard metering system.

“This is something very easy can be done to achieve higher yields. With the John Deere system, you’re losing about 4 ½ bushels per acre, and with eSet, you’re losing about 3 1/3 bushels. So you’re losing somewhere between 3 and 4 ½ bushels per acre for each mile-per-hour increase in speed, and that becomes even more of an issue considering how cropping systems in the MidSouth have changed,” he says.

 In Mississippi, farmers are planting three times as much corn compared to the mid-1990s, says Larson. “We’re trying to cover a lot more acres, especially in years like last year when we didn’t have a lot of time to get into the field. We’re trying to cover a lot of acres in a short amount of time.”

If growers want to optimize yield potential, they obviously need to slow down, says Larson, but they may want to increase their equipment capabilities in order to plant more while achieving optimal yields.