WASHINGTON — The U.S. Department of Agriculture, in its Sept. 12 Crop Production report, forecast 2018 U.S. production of corn at 14,827 million bus, up 1.6% from the August forecast and up 1.5% from 2017. Soybean production was forecast at a record 4,693 million bus, up 2% from August and up 7% from 2017.

Based on Sept. 1 conditions, average corn yield in 2018 was forecast at 181.3 bus an acre, up 2.9 bus from August, up 4.7 bus from last year and the highest on record. Harvested area of corn was forecast at 81.8 million acres, unchanged from August but down 1% from 2017.

The average soybean yield was forecast at a record-high 52.8 bus per acre based on Sept. 1 conditions, up 1.2 bus from August and up 3.7 bus from last year. Harvested area was forecast at 88.9 million acres, unchanged from last month but down 1% from 2017.

If realized, soybean production would be record high, topping the previous record of 4,392 million bus in 2017. Corn production would be the second highest on record after the 2016 record of 15,148 million bus.

The U.S.D.A. corn production and yield forecasts were above the average of trade expectations of 14,530 million bus and 177.8 bus an acre, respectively. The U.S.D.A. soybean production and yield estimates were above trade expectations, which averaged 4,650 million bus and 52.2 bus an acre, respectively.

September corn futures fell more than 3% after the release of the report. September soybeans were trading about 1% higher after the U.S.D.A. numbers were released.