Source: Pioneer Hi-Bred news release

Corn rotated after soybeans generally out yields corn following corn, but there's help for growers choosing corn-after-corn rotations through modern crop technologies, according to crop production experts from Pioneer Hi-Bred, a DuPont business.

The "rotation effect" is an unexplained benefit that results in yield increases for corn following soybeans, compared to corn following corn.

"The rotation effect varies depending on growing conditions," said Steve Butzen, agronomy information manager at Pioneer. "When yield potential is low due to tough soils or lack of rain, the benefit of rotation is highest."

Another benefit with rotating corn and soybeans is the potential to lower the amount of nitrogen needed, says Paul Gaspar, agronomy research scientist for Pioneer. "In years with excess rainfall that leads to nitrogen losses, this advantage may be even more important," Gaspar said.

"The less nitrogen growers have to apply the better for time and input costs," Butzen said. "Rotation also helps control diseases and insects. Continuous corn is a host to many of the corn pests growers have to face."

Also in corn after corn, the plant's root system may be limited due to corn rootworm feeding or soil compaction. This leads to increased plant stress and yield loss in years when demand for soil moisture is high.

"Despite potential yield reductions with a corn-after-corn system, the economic advantages of growing continuous corn have outweighed the benefits of rotation for some growers," Butzen said. "The most successful corn-after-corn producers start with highly productive fields with high water-holding capacity and good drainage. They then manage these fields carefully to minimize compaction, handle excessive residue and maintain soil fertility."

Hybrid selection is another key to corn-after-corn success. Pioneer offers the latest high-performing hybrids that can handle tough conditions.

"Although corn after corn is a more challenging production environment, Pioneer has hybrids and traits that help mitigate the risks," Gaspar said. "Select hybrids with a good disease package, corn borer and corn rootworm resistant traits, and good standability ratings. In addition, Pioneer provides stress emergence ratings and high residue suitability ratings for all corn hybrids. These ratings are assigned specifically to help determine which hybrids work best in corn-after-corn fields."

Seed treatments also help to improve seedling health and should be considered, especially when planting early. Pioneer uses a seed treatment that includes Dynasty fungicide for all corn hybrids. Dynasty has increased activity against several soil fungi that cause corn seedling diseases, Butzen said.

"Pioneer sales professionals can help you choose the right products, traits and seed treatments if you plant continuous corn" Gaspar said. "There are many more options now than there were just 10 to 15 years ago."