June 1 (Bloomberg) -- Soybeans jumped to an eight-month high and corn climbed to more than a seven-month peak on speculation rain may delay planting and damage yields for some crops already seeded in the U.S. Midwest.

Rain that falls over the next few days will hinder planting efforts of farmers, according to a forecast yesterday from AccuWeather.com. Corn sowing remains several weeks behind schedule in parts of the Midwest, it said. In areas where planting has taken place, any new flooding issues could damage existing crops, the forecaster said.

“Forecast for rain this week has stoked concerns over planting delays of corn as well as soybeans,” said Hiroyuki Kikukawa, general manager of research at IDO Securities Co.

Soybeans for July delivery added as much as 1.8 percent to $12.0475 a bushel on the Chicago Board of Trade, the highest since Sept. 24, and were at $12.0175 by 12:19 p.m. London time. The most-active contract rose 1.5 percent last week, climbing for a fifth straight week, and jumped 12 percent in May, the third straight monthly advance. The price touched $12.0075 on May 27, the highest since Sept. 25.

U.S. soybean inventories on Aug. 31, before the harvest, will drop to a five-year low of 130 million bushels from 205 million bushels a year earlier, the USDA said on May 12.

The weaker dollar has boosted demand for soybeans and corn as well as other commodities, Kikukawa said. The dollar weakened to a five-month low of 79.086 today against a basket of six major currencies after losing 7 percent in May, its biggest monthly decline this year.

China Drought

Soybeans in China, the world’s biggest consumer, jumped on speculation government stockpiling and a drought in the country’s major growing region will spur a rally. Palm oil and other oilseed products also advanced.

Heilongjiang province, China’s biggest soybean-growing region, had the lowest recorded May rainfall in almost 60 years, the weather office said today. The government will purchase the new rapeseed crop at a price “slightly higher than the prevailing market price,” the National Development and Reform Commission said yesterday.

Corn for July delivery was 1.2 percent higher at $4.4125 a bushel at midday in London after touching $4.4175, the highest since Oct. 9. The grain rose 8.1 percent in May on speculation planting delays would reduce acreage and yields in the U.S.

Signs of a recovery in the global economy have spurred demand for fuel, metals and crops. Crude oil rose 30 percent in May, the biggest monthly gain in a decade, boosting demand prospects for corn and soybeans as a source for biofuel.

July-delivery wheat rose as much as 2.1 percent to $6.505 a bushel, the highest since Oct. 3, and was at $6.4825 by 12:23 p.m. London time. The most-active contract advanced 19 percent last month, the biggest such gain since September 2007, on speculation that adverse weather will harm U.S. crops.

To contact the reporter for this story: Jae Hur in Singapore at jhur1@bloomberg.net

Last Updated: June 1, 2009 07:46 EDT