Grain futures in Chicago are expected to rise sharply at the open of trading today after U.S. Department of Agriculture reports stoked concern over dwindling grain supplies.

Corn futures may open 10 cents to 30 cents higher and soybean futures may open 20 cents to 60 cents higher, traders and analysts at Chicago-based CME Group said. Wheat futures are called to open 5 cents to 40 cents higher.

Prices are expected to climb largely based on the USDA’s Quarterly Grain Stocks report, which showed both U.S. corn and soybean inventories at the beginning of March below analysts’ expectations.

In a separate USDA report, projected corn plantings this year were slightly above trade forecasts, while soybean acreage was below expectation.

U.S. farmers are expected to seed 92.18 million acres to corn in 2011, up 4.5 percent from 88.19 million in 2010 and the second-highest total since 1944, according to numbers in the USDA’s Prospective Plantings report today. Analysts on average expected corn plantings at about 91.8 million acres, based on a Dow Jones Newswires survey.

Soybean plantings are estimated at 76.61 million acres, down 1 percent from 77.4 million last year, according to the USDA. Based on the Dow Jones survey, soybean plantings were estimated at 76.9 million acres.

The USDA, in its quarterly stocks report, said the nation’s corn supplies as of March 1 totaled 6.52 billion bushels, down 15 percent from the same date a year earlier. Soybean stocks totaled 1.25 billion bushels, down 1.6 percent.

Click here to view the Grain Stocks report.

Click here to view the Prospective Plantings report.