WASHINGTON — U.S. 2010 corn production was forecast at 12,664 million bus, down 4% from 13,160 million bus forecast in September and down 3% from a record 13,110 million bus in 2009, the U.S. Department of Agriculture said in its Oct. 8 Crop Production report. Soybean production was forecast at a record 3,408 million bus, down 2% from 3,483 million bus forecast in September but up 1% from 3,359 million bus last year.

The U.S.D.A. corn production number was below the average pre-report trade estimate of 12,950 million bus.

The U.S.D.A. soybean number also was below the trade average of 3,491 million bus.

Based on Oct. 1 conditions, corn yield was forecast at 155.8 bus an acre, down 6.7 bus from the September forecast and 8.9 bus below the 2009 record of 164.7 bus an acre, the U.S.D.A. said.

“Forecasted yields decreased from last month throughout much of the Corn Belt and Tennessee Valley,” the U.S.D.A. said. “Illinois showed the largest decline, down 14 bus per acre. Indiana and Iowa are both down 10 bus from the previous month, while Missouri and Nebraska declined nine bus per acre.”

Corn area harvested for grain in 2010 was forecast at 81.3 million acres, up slightly from September and up 2% from 2009, the U.S.D.A. said.

Soybean yield based on Oct. 1 conditions was forecast at a record 44.4 bus an acre, down 0.3 bu from September but up 0.4 bu from the previous record high of 44 bus in 2009. Harvested area was forecast at 76.8 million acres, down 1% from September but up 1% from 2009.

The 2010 rice crop was forecast at 242,260,000 cwts, down 5% from 255,319,000 cwts forecast in September but up 10% from 219,850,000 cwts in 2009.

Sorghum production in 2010 was forecast at 337,229,000 bus, down 10% from 376,469,000 bus in September and down 12% from 382,983,000 bus in 2009, the U.S.D.A said.