US corn futures firmed on Friday after the US Department of Agriculture lowered its US yield and harvest forecasts in a monthly crop report, though gains were kept in check by worries about weak demand.
Soyabeans fell as the USDA left its US crop yield and harvest outlooks unchanged despite poor weather this summer and fall that had many market observers expecting cuts.
The forecast, in a monthly USDA crop supply-and-demand report released at midsession, added to earlier pressure stemming from renewed concerns about an interim US trade deal with China.
Wheat briefly traded higher in tandem with corn but retreated as the USDA's cuts to US and southern hemisphere production were more than offset by larger crops in the EU and Black Sea region.
The USDA forecast corn production of 13.661 billion bushels, based on an average yield of 167.0 bushels per acre (bpa). Analysts had been expecting production to fall to 13.643 billion bushels, and a yield of 167.5 bpa.
The agency pegged the soya crop at 3.550 billion bushels, with yields seen at 46.9 bpa, unchanged from October.
Chicago Board of Trade (CBOT) December corn was up 1-1/2 cents at $3.76-3/4 a bushel at 12:50 p.m. CST (1850 GMT). If the gain holds, the modest gain would be the contract's first price increase in seven sessions.
January soyabeans fell 7-1/2 cents to $9.29 a bushel, while CBOT December wheat dropped 3-1/2 cents to $5.09 a bushel. Renewed concerns about an interim US-China trade deal weighed on the market ahead of the report, particularly soyabeans.
Earlier on Friday, the USDA confirmed private sales of 270,000 tonnes of US soyabeans and 217,040 tonnes of corn to undisclosed buyers via its daily export sales reporting system. Large soya purchases reported for unknown buyers are often assumed to be bound for China.