OMAHA, Neb. — The amount of American cropland devoted to corn is expected to shrink about 4 percent this year as farmers devote more acres to soybeans, the U.S. Department of Agriculture said Monday.

The USDA said it expects 91.7 million acres of corn to be planted this year, down from 95.37 million acres last year. The acreage devoted to soybeans is expected to grow about 6 percent to 81.5 million acres from last year's 76.5 million acres.

Iowa farmer Ray Gaesser said farmers are responding to predictions for tight soybean supplies and relatively high crop prices. Gaesser, who serves as president of the American Soybean Association, said demand for soybeans is clearly high going into this year.

"There will undoubtedly be more soybeans planted," Gaesser said.

Over the last several years, farmers planted more corn in response to strong prices for that crop thanks to growing international demand and increasing ethanol production.

Now farmers are shifting land back to a more normal split between corn and soybeans because corn prices have cooled after the government proposed reducing the amount of ethanol that must be blended with gasoline in 2014.

Iowa State University agricultural economist Mike Duffy said the shift will likely reduce corn stockpiles a bit and improve soybean supplies. But it's difficult to forecast what impact that will have on the harvest or food prices.

"The consumer impact is going to be a little harder to say," Duffy said.

And the weather over the course of the year will play a major role in determining just how plentiful the harvest will be. For instance, several states in the Plains and Southwest are still dealing with droughts that could hamper crops.

Farmer Doug Nelson said he'll wait until later this spring to decide what to plant on one field, but the rest of his 5,000 acres have already been fertilized for either corn or soybeans.

"I'm not changing my rotation significantly," said Nelson, who farms in northeast Nebraska near Wayne. "It's still pretty close to 50-50 corn and soybeans."

Jerry Ackerman said he normally grows one-third corn, one-third soybeans and one-third alfalfa on about 1,000 acres in southwest Minnesota.

This year Ackerman will plant more soybeans than corn, but that is a byproduct of losing part of his alfalfa crop last year and planting corn on those fields. Normally, he sticks pretty close to his rotation to replenish nutrients in the soil.

"I've got 80 percent of my crops sold already, so I feel comfortable," Ackerman said.

For many farmers, like Gabe Brown, the benefits of sticking to a set rotation of crops far outweighs the short-term gains that might be had by planting more of a particular crop when prices are high. Rotating crops helps control pests and weeds.

"I don't vary my rotation at all according to prices," said Brown, who farms near Bismarck, N.D. "Our rotation is based on soil health."