U.S. soybean futures tumbled more than 2.5 per cent on Monday, reversing similar gains from the previous session, as a record-fast harvest pace and reports of larger-than-expected yields pressured prices.
Wheat futures dropped two per cent, the fifth decline in six sessions, in a profit-taking setback and as rain forecast for the drought-parched U.S. Plains was expected to boost winter wheat seeding.
Corn futures traded mixed as spillover pressure from sharply lower soy and wheat offset lingering support from a U.S. government report on Friday that showed stockpiles of the grain had dropped.
U.S. corn surged by the daily trading limit on Friday, jumping 5.6 per cent after the U.S. Department of Agriculture (USDA) shocked markets with a report that end-of-season stocks tumbled 12 percent from a year ago, coming in under one billion bushels for the first time in eight years.
Soybeans added nearly two per cent on Friday despite a larger-than-expected USDA stocks figure, while wheat gained 5.5 per cent in the steepest rally in three months as the USDA reported an unexpected drop in U.S. wheat stocks.
The corn and soybean harvests maintained a record pace as dry weather allowed farmers to notch their best crop-gathering week of the year.
After the market closed, USDA said U.S. corn was 54 per cent harvested as of Sunday while 41 per cent of soybeans were harvested.
Soy futures prices also came under pressure from more reports of stronger-than-anticipated soybean yields as timely August rains in many areas revived the crop after the summer's severe drought.
"Soybean yields, from start to finish, have been better than expected," said Jim Gerlach, president of A/C Trading in Fowler, Indiana.
"Any time you've got yields rising and you're in the middle of harvest and you've got the funds relatively long, it's very difficult to sustain a market. You have to feed a bull market every day and there's nothing to feed it right now," he said.
Cash markets slumped on rising supplies of newly harvested soybeans, dragging basis bids down as much as 20 cents a bushel at elevators and processors in the Midwest (all figures US$).
Rain in soybean production areas of Brazil, where farmers were preparing to plant what may be a record-large crop, also weighed on soy prices. Brazilian analysts Celeres raised their forecast for the country's soy crop by nearly one million tonnes to a record 79.08 million tonnes.
Benchmark November soybeans on the Chicago Board of Trade fell for the third time in four sessions, declining 40-3/4 cents, or 2.6 per cent, to $15.60-1/4 per bushel.
CBOT December corn rose to a two-week high of $7.68-1/2 a bushel but settled up just half a cent at $7.56-3/4.
Commodity funds sold an estimated net 10,000 soybean contracts on the day, after buying a net 13,000 on Friday, trade sources said. In corn, funds were net even on the day after buying a net 28,000 on Friday, they said.
Wheat prices plunged in a profit-taking pullback from Friday's sharp gains, which were triggered by an unexpected drop in wheat stocks in a USDA report, and as weekend rains soaked key areas of the U.S. Plains hard red winter wheat belt.
U.S. futures extended declines at midmorning, pressured by a weak futures market close in Europe.
"The European markets took a pretty sharp nosedive in the last hour of trading and that bled over into the Chicago and Kansas City markets," said Mike Zuzolo, president of Global Commodity Analytics.
"The weekend rains in the Texas and Oklahoma hard red winter wheat belt were better than probably the trade was anticipating," he said.
CBOT December soft red winter wheat fell 18-1/4 cents to $8.84-1/4 a bushel, a two per cent decline that was the steepest in two weeks. December hard red winter futures on the Kansas City Board of Trade shed 20-1/2 cents, or 2.2 per cent, to $9.07 a bushel.
Commodity funds sold an estimated net 5,000 Chicago wheat contracts on Monday after buying a net 7,000 in the previous session, trade sources said.
Benchmark November milling wheat on the Paris futures market ended down 3.25 euros, or 1.2 per cent, at 262.50 euros a tonne after jumping three per cent on Friday.
-- Karl Plume writes for Reuters from Chicago. Additional reporting for Reuters by Michael Hogan in Hamburg and Naveen Thukral in Singapore.