CHICAGO, Jan 9 (Reuters) - U.S. corn futures fell on Monday for the sixth time in seven sessions and wheat and soybeans finished mostly lower, as investors weighed weather-reduced production in some areas of South America against tepid demand for U.S. supplies.
Wheat futures also retreated as late-session technical selling eroded earlier support from a weaker dollar and fund short-covering.
Chicago Board of Trade March wheat ended down 2 cents at $7.41-1/2 per bushel. March soybeans fell 4 cents to $14.88-1/2 a bushel while March corn was down 1-1/4 cents at $6.52-3/4 a bushel.
Grain traders remained cautious ahead of Thursday's global crop supply-and-demand estimates from the U.S. Department of Agriculture (USDA). In the report, USDA is expected to cut its corn and soy production outlook for drought-hit Argentina but also raise its estimate of U.S. grain and soybean supplies.
"The question going into the report is whether the USDA will lower the South American production and supply numbers enough to offset weakening demand that the market has already built in," said Mike Zuzolo, president of Global Commodity Analytics.
The USDA on Monday reported weekly grain export inspections for corn, soybeans and wheat near the low end of a range of trade estimates. U.S. exports have struggled to compete in the global marketplace with cheaper South American supplies.
Grain traders are also monitoring developments in Brazil, where supporters of far-right former President Jair Bolsonaro stormed government buildings on Sunday. The Brazilian real weakened against the dollar on Monday, making the country's crop exports even more affordable than U.S. supplies on the global market. (Additional reporting by Michael Hogan in Hamburg and Naveen Thukral in Singapore; Editing by Rashmi Aich, Jane Merriman, Richard Chang and Paul Simao)
