While it's been known for a long time that young corn plants are typically shorter in continuous no-till corn fields, Tony Vyn maintains this doesn’t mean there is an overall lack of plant height across a field.

Instead, the Purdue University agronomist says residue left over from the previous year’s corn crop can result in changing soil conditions, which can create a disadvantage for some plants when it comes to competing for sunlight and nutrients.

Vyn has found that no-till yield reductions in corn have little to do with any overall height reduction early in the growing season. Instead, decreased yields have more to do with height variability during the crop’s vegetative growth stage.

14% Yield Difference

He’s attributed yield losses of up to 14% to plant competition when corn is no-tilled after a previous corn crop.

In these fields, the remaining corn residue creates patches with lower soil temperatures and varying water and nutrient content. Corn plants in these areas of a field are at a distinct disadvantage with conditions created by the residue having an impact on root development.

“Plants that have better access to resources grow faster and then dominate their smaller neighbors,” Vyn says.

By evaluating plant height data over 14 years, Vyn found significant height differences among plants stretching out as long as 4 weeks.

“For example, competition for nitrogen increases as crowding increases,” he says. “The higher the density, the greater the intensity of the competition for all resources.”

Vyn says one misconception among…