Larson and other researchers have also looked at narrow –row systems, and the interest in those has increased along with corn and soybean acreage in the MidSouth. “As you transition into a soybean/corn production system, there’s a whole lot more potential there for you to realize benefits from narrow-row systems.”

In addition to narrow rows, researchers also looked at twin rows, says Larson. “We wanted to look at the yield capability of corn in 30-inch rows versus the wider 38 to 40-inch rows. We also looked at that same 38 to 40-inch row in twin rows, to evaluate the pluses and minuses and put some MidSouth numbers to them.”

The trials involved different hybrids and various plant populations, he adds.

“We also looked at this in an irrigated culture. Nearly 50 percent of our corn in Mississippi is grown under irrigation, and we wanted to optimize the yield potential to see how corn might perform in the narrow-row systems versus the wide traditional systems.”

Light interception was an important consideration, says Larson. “It’s important because that’s the goal of the plant’s vegetation – to intercept as much light as possible. You want to be intercepting from 90 to 95 percent of the available light during the day when the sun is overhead to optimize yield potential. If you narrow those rows, you obviously have more potential to do that because you don’t have more light getting down into the middle of the rows, and the light is spread out over the leaves of those plants where it’ll be used more efficiently.”

Research results were pretty much as expected, he says. “The wide single rows had the lowest amount of light interception, the twin rows increased it a little, and the narrow rows increased it even further.”

However, he adds, light interception did not necessarily translate into higher yields for the twin-row systems. “It doesn’t mean the potential isn’t there. For one reason or another, we just weren’t realizing our potential for the yields in twin rows.”

The bottom line, says Larson, is that of those three systems, there was a significant advantage for the narrow rows, with yields 8 to 9 percent higher in the 30-inch rows than in either of the wide-row systems.

This is consistent with similar research from the Corn Belt, he says.

“Twin rows did not improve yield, though they did improve light interception. I think the reason that twin rows didn’t work quite as well in terms of yield were issues associated with raised-bed systems. I don’t think you would have seen some of the same stand issues with flat-planted corn.”

Corn has a determinate growth habit, and that’s important in terms of its inability to compensate whenever there are issues early in the season, says Larson.