WASHINGTON — U.S. 2013 corn production was forecast at 13,843,320,000 bus, up 80,295,000 bus, or about 1%, from 13,763,025,000 bus forecast in August and up 28% from 10,780,296,000 bus in 2012, the U.S. Department of Agriculture said it is Sept. 12 Crop Production report. Soybean production was forecast at 3,149,166,000 bus, down 106,278,000 bus, or about 3%, from 3,255,444,000 bus forecast last month but up 4% from 3,014,998,000 bus last year.

If realized, corn production would be record high and soybean production would be the fourth largest on record, the U.S.D.A. said. Wheat production estimates will be updated in the U.S.D.A.’s Sept. 30 Small Grains Summary.

The U.S.D.A. corn number was above the average pre-report trade estimate of 13,646 million bus. The soybean number matched the pre-report average of about 3,149 million bus.

New crop corn futures prices dropped about 10c a bu immediately after the report was released at 11:00 a.m. Central Time, while soybean futures were mixed but mostly higher.

Based on Sept. 1 conditions, corn yield was forecast at 155.3 bus an acre, up 0.9 bus from 154.4 bus an acre forecast in August and up 31.9 bus from 123.4 bus an acre in 2012 and the highest average yield since 2009, the U.S.D.A. said. Harvested area was forecast at 89,135,000 acres, unchanged from August but up 2% from 87,375,000 acres in 2012.

“The Sept. 1 corn objective yield data indicate the highest number of ears on record for the combined 10 objective yield states,” the U.S.D.A. said.

Soybean yield was forecast at 41.2 bus an acre, down 1.4 bus from 42.6 bus an acre forecast in August but up 1.6 bus from 39.6 bus an acre in 2012. Harvested area was forecast at 76,378,000 acres, unchanged from August but up slightly from 76,104,000 acres in 2012.

“The September objective yield data for the combined 11 major soybean producing states indicate a higher pod count compared with last year as conditions have generally been more favorable across the Midwest,” the U.S.D.A. said.

U.S. 2013 rice production was forecast at 185,077,000 cwts, up 2% from 181,364,000 cwts forecast in August but down 7% from 199,479,000 cwts in 2012.

Sorghum outturn in 2013 was forecast at 396,105,000 bus, up 10% from 358,892,000 bus forecast in August and up 60% from 246,932,000 bus in 2012.