Chicago agricultural commodity futures went down across the board Wednesday over better-than- expected output forecast and heavy technical selling.

The most active corn contract for December delivery fell 5.75 cents, or 1.21 percent, to 4.695 dollars per bushel. December wheat lost 1.0 cents, or 0.15 percent, to settle at 6.4625 dollars per bushel. November soybeans went down 34.25 cents, or 2.47 percent, 13.525 dollars per bushel.

According to Chicago Mercantile Exchange, corn futures traded lower for the second day in a row. Soybeans dropped sharply, adding pressure to peripheral agricultural commodity markets. Wheat futures also traded slightly lower, mostly in line with weaker corn and soybean markets.

The U.S. Department of Agriculture pegged August corn crop at 13.676 billion bushels. Corn fell as harvest moves forward. Meanwhile, soybeans also saw double digit losses on spillover pressure from the overnight session and weak technical signals.

A private advisory firm estimated the soybean crop at 2.98 billion bushels with a yield of 39 bushels per acre. The final yield for the 2012-13 period was estimated at 39.6 bushels per acre with production at 3.015 billion bushels amid the worst drought. However, timely rainfall at the end of August last year helped to push yields higher in some areas.