Chicago Board of Trade (CBOT) grains futures went down sharply on Thursday with corn, wheat and soybean futures dropping more than three percent, after the U.S. Department of Agriculture (USDA) crop forecast turns out to be well above average trade estimates.

The most active corn contract for December delivery dropped 15.25 cents, or 3.95 percent, to 3.71 dollars per bushel. September wheat delivery went down 19 cents, or 4.13 percent to 4.405 dollars per bushel. November soybeans delivery fell 33 cents, or 3.39 percent to 9.4025 dollars per bushel.

In the outside markets, the Brent crude oil market is 0.97 dollar per barrel lower, the U.S. dollar is lower, and the Dow Jones Industrials are 124 points lower.

For soybeans, the USDA pegged the 2017 production at 4.38 billion bushels vs. the USDA's July estimate of 4.26 billion and the average trade estimate of 4.212 billion.

The USDA estimated U.S. production of spring wheat other than durum at 402 million bushels, down from 423 million in July but well above the average trade estimate of 393 million.

Jack Scoville, the PRICE Futures Group's senior market analyst, says that the report's yields are very high and imply much better crops than what he saw last weekend in central Illinois.