U.S. soybean futures turned lower on Thursday on profit-taking, after hitting a six-week high on Wednesday, as forecasts for better crop weather in South America eased concerns about harvest delays and production losses there.
Corn posted an eight-week high overnight, tumbled along with soybeans as investors pocketed profits, then rallied back on late-session fund buying to close near unchanged.
Wheat fell along with soybeans.
"The market's rallied pretty significantly in the last few sessions so on the final day of the month it's no surprise to see a little profit-taking," said Karl Setzer, a commodity trading adviser and market analyst at MaxYield Cooperative.
All eyes have been on South American weather this week as overly wet conditions stalled early soy harvest in Brazil and persistently dry weather threatened corn and soybean crops in neighbouring Argentina.
Crops from both major exporters are crucial for replenishing tight global supplies.
"It's not quite as wet in Brazil and it's a little wetter in Argentina," said Art Liming, futures specialist at Citigroup.
Chicago Board of Trade (CBOT) March soybeans fell 10-1/4 cents, or 0.7 per cent, to $14.68-1/2 per bushel (all figures US$). The contract, which struck a six-week high on Wednesday, rose this month for the first time in five months, adding 3.1 per cent.
Robust export demand for new-crop U.S. soybeans limited declines in back-month contracts.
The U.S. Department of Agriculture on Thursday reported stronger-than-expected export sales last week and confirmed a large U.S. soybean sale to China for delivery in the 2013-14 marketing year, the third big sales confirmation this week.
Corn export demand remained sluggish. USDA reported sales last week that were only about a quarter of the sales in the same week last year.
But pressure in the corn futures market was offset by tight U.S. stocks and a firmer cash market.
"Corn is holding a little stronger than the rest due to the cash market tightening around the Midwest. We've seen a little bit of an improvement in ethanol margins so there's some speculation that domestic corn demand might perk up," MaxYield's Setzer said.
CBOT March corn rose 1/4 cent to $7.40-1/2 per bushel after hitting an eight-week high overnight. The spot contract climbed 6.1 per cent this month, its first monthly gain in six months.
Commodity funds bought an estimated net 5,000 corn contracts on the day and sold a net 4,000 contracts each of soybeans and wheat, trade sources said.
CBOT wheat for March delivery declined 7-1/2 cents, or one per cent, to $7.79-1/2 per bushel. The spot wheat contract gained 1-1/2 cents in January, the first monthly gain in four months.
-- Karl Plume writes for Reuters from Chicago. Additional reporting for Reuters by Gus Trompiz in Paris and Naveen Thukral in Singapore.