Soybeans may rise to a record $20 a bushel, more than double today's price, amid low stockpiles in the United States, a weaker dollar and increased demand as the global economy recovers, according to Standard Chartered Plc.

"Historically, August is the most volatile time for beans because that's the pod-setting period in the U.S.," says John Reeve, the bank's director for agricultural commodities. "It's a late crop this year."

The United States grows more than a third of the world's soybeans and the country's inventories are at a 5-year low, according to Department of Agriculture data. Prices may swing between $8 a bushel and $20, Reeve says. The crop, crushed to make animal feed and cooking oil, touched a record $16.3675 a bushel in 2008.

"I am little bit more bullish than bearish" on soybeans, Reeve says. "An economic recovery, particularly in Asia, which of course is the majority market for exported beans out of the Americas, a lower dollar, all that macro stuff, given the tight stocks of beans in the U.S." may boost prices.

Soybeans for December delivery, the most-active contract, climbed as high as $9.975 a bushel Tuesday on the Chicago Board of Trade. The contract is little changed this year, having risen about 1.4%.

Professional Farmers of America, an information company that produces crop estimates, said last week that the U.S. soybean harvest may be 3.15 billion bushels this year. That compares with a government estimate of 3.199 billion bushels.

"There are some early signs that's not going very well," Reeve says, referring to the U.S. soybean crop. The focus for supply then shifts to South America, he adds.

Argentina, suffering from drought, and Brazil are the largest producers after the United States. The South American crop is planted in the fourth quarter, after the U.S. crop is harvested.

"We could see higher corn prices" should demand pick up amid the economic recovery and a weaker dollar, Reeve says. Still, "at this stage, the crop is looking very healthy, I think there's a potential of lower corn prices."

Corn prices in Chicago have dropped 19% this year and last traded at $3.29 a bushel. Pro Farmer forecast U.S. corn output at 12.807 billion bushels, more than the 12.761 billion estimated by the Department of Agriculture on Aug. 12.