Chicago wheat futures fell to new contract lows on Wednesday, while soybeans and corn were little changed as participants awaited the US government's global crop report and South American production data.

Corn rebounded from its own three-year low last month, but heavy volumes overseas, plus competition from Ukrainian corn for China, limited gains.

A weaker dollar and higher crude oil levels provided some support to grains, although investors remained awaiting the conclusions to be made before the US Congress by the head of the US Federal Reserve.

Global wheat futures have been hammered in recent weeks by falling prices in Russia, and results reported by traders at the Algerian auction on Tuesday highlighted strong export competition.

"In Europe, competitive pressure from Black Sea wheat is pushing prices down, which in turn is dragging down US wheat," commented Agritel, a consulting company.

Algeria's state grain agency (OAIC) ​​is believed to have bought about 870,000 to 900,000 tonnes of optional wheat at $227 to $228 a tonne CIF, European traders said, most likely to be sourced from the region of the Black Sea.

"It makes sense for Algeria to buy a lot at these low prices, but the purchase surprised the market because it appears traders had larger-than-expected quantities to sell," a European trader said.