WATERLOO -- Farmers looking for help when it comes to grain marketing may want to keep an eye on crude oil prices and the stock market.

Supply and demand is no longer the only game in town when it comes to dictating corn and soybean prices, according to agriculture experts and economists. Commodity prices are following the lead of Wall Street and energy costs.

Iowa State University Extension hosted an Ag Outlook and Management Seminar last week at Hawkeye Community College. About 45 agribusiness officials attended, seeking guidance for future decision making.

Chad Hart, ISU Extension grain economist, said the Dow Jones Industrial Average and crude oil prices are controlling commodity prices. Keeping a close tab on these indicators may provide insight on when to sell corn and beans and how much.

"It's very rare we actually look at ag fundamentals," Hart said. "Outside influences are driving prices."

Corn and soybeans soared to record highs this summer, at nearly $8 and more than $16 per bushel, respectively. Fears of a poor harvest, which didn't materialize, due to bad weather contributed to the run-up.

The nation's farmers are bringing in the second-biggest corn and fourth-largest soybean crop in history, the latest government projections indicate. Yet, Hart said 2008-09 ending stock for corn and soybeans are forecasted to be lower or the same as last year, due to demand. The estimates, which he said he considers tight, put the corn carryover at 1.1 billion bushels and 205 million bushels for soybeans.

Despite these projections, current grain prices have tumbled by about half compared to midsummer highs.

Hart said the drop in crude oil prices and the economy is a big reason why.

Corn and soybeans are used to make ethanol and biodiesel. The price of both biofuels are closely linked to oil and gas.

As the world's economy plummeted this summer, oil prices fell by 60 percent in the last four months after reaching nearly $150 per barrel in July. The Dow Jones Industrial Average, a primary indicator of the nation's economy, plummeted from more than 12,600 points on June 6 to a little more than 8,830 on Thursday.

If the stock market improves, it's likely oil prices will go up again and bring grain prices along for the ride, officials said.

"When conditions are good, corn is selling at (or) close to its energy value," said Dermot Hayes, ISU Extension agriculture economist.

Craig Chase, an ISU Extension farm management field specialist, said farmers and ag lenders need to look at the worldwide economic picture when making business decisions.

Many producers are working on their 2009 budgets as the 2008 harvest continues.

"(They're) looking at futures markets and trying to figure out where (they're) going to be sitting at," Chase said.

Contact Matthew Wilde at (319) 291-1579 or matt.wilde@wcfcourier.com.