Across the Midwest, we expect to see an increase in acreage planted to corn over previous years because of the demand for grain from several markets, including livestock and ethanol. In addition to these market-driven factors is the uncertainty surrounding soybean production, including possible increased management costs for disease protection. The effectiveness of a corn-soybean rotation in controlling corn rootworm also has been reduced, lessening the incentive to rotate crops.

Although corn yields continue to increase 1.75 bushels per acre per year nationwide (see Figure 1), this increase will not come close to meeting the future demands for grain. The only way to meet the demand is to increase acreage devoted to corn production. The increase in corn acres will almost entirely come from a reduction in soybean acreage. In Iowa, producers have generally planted a corn-soybean rotation. Corn and soybean acres started to trend differently in 2001 (see Figure 2), as the gap between them began widening again in favor of corn. In 2006, the ratio of corn to soybean was 55:45, with nearly 13 million acres of corn.

Lori Abendroth is an agronomy specialist with research and extension responsibilities in corn production. Roger Elmore is professor of agronomy with research and extension responsibilities in corn production.