Chicago soybeans ticked lower on Thursday after hitting a two-month high in the previous session, although losses were limited by expectations that China would loosen its Covid-19 rules, boosting demand in the world's top importer of the oilseed.
Wheat fell on pressure from ample Black Sea supplies, while corn lost ground.
The most-active soybean contract on the Chicago Board of Trade (CBOT) Sv1 fell 0.3% to $14.64-3/4 a bushel, as of 0127 GMT, after climbing to its highest since 21 Sept at $14.78-1/2 on Wednesday.
Wheat Wv1 lost 0.5% to $7.91-1/2 a bushel and corn Cv1 gave up 0.5% to $6.64 a bushel.
Expectations that China would ease restrictions that have triggered rare public protests sparked demand hopes.
Chinese cities of Guangzhou and Chongqing announced an easing of Covid curbs on Wednesday, a day after demonstrators in southern Guangzhou clashed with police amid a string of protests against the world's toughest coronavirus restrictions.
US exporters sold 136,000 tonnes of soybeans for delivery to China during 2022/23, the US Department of Agriculture said.
Argentine farmers nearly doubled soybean sales on Tuesday from the day before, the major Buenos Aires grains exchange said, after a preferential exchange rate went into effect for exports of the cash crop.
Cheap supplies from Russia and elsewhere in the Black Sea region were keeping a lid on wheat futures.
Around 450,000 tonnes of Ukrainian grain are being transported via Poland monthly, over 50% more than in the middle of the year, Poland's infrastructure minister said on Wednesday, as Warsaw helps its neighbour to increase its food exports.
Ukraine is one of the world's leading grain and oilseed exporters and a Russian blockade of its ports after Moscow invaded the country in February drove a quest for alternative routes.
The US Environmental Protection Agency will propose increases in the amount of ethanol and other biofuels that oil refiners must blend into their fuel over the next three years, two sources familiar with the matter said.
Commodity funds were net buyers of CBOT wheat, soymeal and soybean futures contracts on Wednesday and net sellers of corn and soyoil futures, traders said.
Wall Street equities closed sharply higher on Wednesday while US Treasury yields declined and the dollar sank after Federal Reserve Chair Jerome Powell said the central bank could slow the pace of interest rate hikes "as soon as December," even as he cautioned that inflation was still too high.