A 2007-2011 study by economists at the Illinois Farm Business Farm Management Association, or FBFM, demonstrated that intensifying corn production when corn prices are high didn’t add much to profits. Higher seed and fertilizer costs, greater fuel and machinery needs, and yield drag in continuous corn sucked the extra return out of the extra corn acres and pulled it down much closer to the profitability of corn-soybean rotations.

University of Illinois agricultural economist Gary Schnitkey drew the same conclusions from his comparison of returns from continuous corn vs. various rotations.

“Adding more corn to a one-half corn/one-half soybean rotation often increases short-run returns and decreases long-run returns,” he explains.

Corn returns have higher variability than soybean returns do, Schnitkey explains, so adding corn acres increases risk. When he evaluated rotations through the University of Illinois’ Planting Decision Model in 2011, Schnitkey found that corn after soybeans had a return of $559 per acre, while corn after corn returned $491 per acre.

That corn-after-corn profit is still more than the return on soybeans, but planting extra corn today means more acres will suffer the corn-after-corn yield lag in the future, dragging down profits in the long term.

“There’s no magic bullet out there that will solve all the problems in trying to boost yields,” says Lauer. “However, utilizing good crop rotations can play a key role in reducing some of the risk and in sustaining good yields over time.”