CHAMPAIGN, Ill. — Shares of Archer Daniels Midland Co. fell more than $2 to close at $36.60 Tuesday after the nation’s largest ethanol producer reported a profit increase for the third fiscal quarter that fell short of Wall Street expectations.

Net income for the three months ending March 31 rose to $362.9 million, or 56 cents per share, up from $347.8 million, or 53 cents per share, during the same period last year.

Revenue at the Decatur, Ill.-based company, also one of the world’s largest food processors, rose 25 percent to $11.38 billion from $9.12 billion a year earlier.

The consensus forecast of 11 analysts surveyed by Thomson Financial called for earnings of 61 cents a share on revenue of $9.65 billion.

ADM has a soybean processing plant in Lincoln.

Chief Executive Office Patricia Woertz, who joined the company just over a year ago, said ADM’s performance during a quarter that included high prices for the corn that the company buys to make many of its key products convinced her that it is well positioned for the quarters ahead.

“I am actually more convinced this quarter that we have the ability to manage through challenges,” she said during a conference call with analysts. “It actually increases my confidence for the long term.”

Corn processing profits increased during the quarter ended March 31 to $252 million, up 14.4 percent, despite increased corn costs.

Some analysts on a company conference call who were caught off guard by ADM’s results, raised tough questions about why the company fell short of expectations.

ADM said in particular that its results were weighed down by a 48 percent drop in profit in its agricultural services division, to $41 million. Ag services includes transport and storage of farm commodities, and Woertz blamed the results on, among other things, frozen rivers that idled barge traffic.

“Frozen rivers have to happen every winter,” challenged Prudential Equity Group analyst John McMillin, who also disagreed with Woertz’s characterization of the company’s earnings as solid.

“It’s not true — rivers don’t always freeze,” Chief Financial Officer Doug Schmalz countered. “When that happens … that affects your costs of carrying the inventories.”

ADM’s oilseeds processing operating profit also decreased, it said, due to lower biodiesel processing margins. Profit in the division, which includes processing soybeans used to make biodiesel, fell 4.5 percent to $169 million.

Other analysts on Tuesday said the big American corn crop anticipated this year should push down the price that ADM and others pay for corn, strengthening ADM’s profits in the quarters ahead. The U.S. Department of Agriculture projects that farmers will plant 90.5 million acres of corn this year, a 15 percent increase over 2006.

Further, Citibank analyst David Driscoll wrote in a note to investors, continued high fuel prices and demand for high-fructose corn syrup should bode well for ADM.

“We believe we are in the strongest environment for agriculture in at least the last decade,” wrote Driscoll, who has a buy recommendation on ADM shares. “Given the company’s broad agricultural product array, we believe it can and will benefit from this overall theme.”