May 18 (Bloomberg) -- Global agricultural production must rise to curb surges in grain prices, even as the world financial crisis temporarily reduces demand, executives from Deere & Co., Bunge Ltd. and Syngenta AG said.

Corn, wheat, rice and soybeans, which rose to records in 2008, may climb again after larger crops and lower demand pushed prices down, the executives said today at the World Agricultural Forum in St. Louis. Output will need to double by 2050 even as climate change, soil degradation and scarcity of arable land reduce it by 25 percent, the United Nations said in February.

“We need to grow more from less” as the world’s population rises and the amount of farmland declines, David Morgan, the president of Syngenta Seeds Inc., said at the biennial conference, which brings together corporate executives, government agriculture ministers and nongovernmental organizations to discuss sustainable methods of boosting food production.

Global food prices have fallen by a third from their June 2008 peak after rising 73 percent in the preceding two years, according to UN data. The prices farmers pay for fertilizer, chemicals, pesticides and other inputs have moved less dramatically, down in the U.S. by 6.8 percent from their August peak.

Shares Fluctuate

Agricultural companies have seen their shares jump and plunge as prices fluctuated. Archer Daniels Midland Co., the world’s largest grain processor, reached a record $48.95 a share in April 2008 before falling as low as $13.53 six months later then rebounding to close at $25.17 on May 15, Bunge, the biggest soybean company, is worth less than half its January 2008 record, while Syngenta, the biggest maker of farm chemicals, is down about 25 percent from a June peak.

U.S. net farm income is expected to fall 20 percent to $71.2 billion as exports from the world’s largest food-shipping nation decline 17 percent to $95.5 billion, according to the USDA. Bob Young, the chief economist at the American Farm Bureau Federation, said the reduced income may cause farmers to delay purchases of such products as AgCo Corp. tractors, Agrium Inc. fertilizer and Monsanto Co. seeds.

Still, long-term prospects worldwide for farm investment remain strong, according to J.B. Penn, the chief economist for Deere, who also spoke at the forum’s opening day.

Foreign investment in Sudanese agricultural land will increase fivefold to cover 5.4 million acres (2.2 million hectares) within five years as countries work to boost food security, Abdeldafi Fadlalla, Sudan’s federal agricultural commissioner at its Investment Ministry, said May 5.

To contact the reporters on this story: Alan Bjerga in Washington at abjerga@bloomberg.net.

Last Updated: May 18, 2009 11:35 EDT