Chicago Board of Trade corn and soybean futures fell on Tuesday, pressured by reports of better-than-expected yields from the ongoing harvest in the U.S. Midwest.
U.S. wheat futures were mixed, with the market receiving fundamental support on concerns about acreage cuts in Black Sea countries due to muddy conditions in the fields.
Corn was the leader on the downside, flirting with three-year lows as fields in places like Iowa and Illinois dried out and farmers rolled their combines.
"We do have a fair amount of harvest activity going on," said Bill Gentry, a broker at Risk Management Commodities. "We kind of thought that maybe some of these yield numbers were going to taper off going deeper into harvest but so far, we have not seen a strong indication in that direction."
The U.S. Agriculture Department did not provide an update on harvest activity on Monday afternoon due to the partial shutdown of the federal government but analysts estimated that farmers had cut 20 per cent of their soybeans and 22 per cent of their corn as of Oct. 6.
"Yield reports, where you can get them, haven't changed, ranging from 'about as expected' to 'way above what we were looking for,' and we are impressed by how many 200-plus bushel-per-acre yields we are hearing this year," ED+F Man Capital's Charlie Sernatinger said in a research note, referencing the corn harvest.
CBOT corn for December delivery settled down 7-1/2 cents at $4.41-3/4 a bushel. CBOT November soybeans dropped 7-3/4 cents to $12.88-3/4 a bushel, snapping a four-session winning streak (all figures US$).
Wheat futures were firmer across the board during the overnight session but the benchmark CBOT December soft red winter wheat contract hit resistance as it neared $7 a bushel, a level it has not breached since June. CBOT December wheat closed down 1-1/4 cents at $6.93-1/2 a bushel.
But MGEX spring wheat and KCBT hard red winter wheat remained firm, bolstered by strong export demand for high-protein supplies. KCBT December hard red winter wheat rose four cents to $7.60-1/2 a bushel while MGEX December spring wheat gained 3 cents to $7.53-1/4 a bushel.
"The key story for wheat is loss of planted acres in Russia for the winter crop," said Brett Cooper, senior markets manager at INTL FCStone Australia. "People are talking about seven million tonnes of loss in production."
Rain will cut the area Russia sows for winter grains by one-fifth compared with the official forecast, the country's agriculture ministry said on Monday, fuelling speculation that 2014's winter wheat crop could fall.
Ukraine's wheat harvest could be down by a third to about 15 million tonnes in 2014 from around 22 million tonnes this year because heavy rains will cut the sowing area, the country's agriculture minister said on Friday.
Trading volume in the ag commodities was light, with a lot of speculators staying out of the market because the U.S. government was unable to provide new reports.
"There is a lot of uncertainty with the U.S. government shutdown turning off the flow of U.S. crop data," a European trader said.
USDA said it will not issue its key monthly crop report and world supply and demand estimates on Friday because of the shutdown.
"This, in turn, leaves the market in a bit of a fog," Societe Generale said in a note, adding investors were reliant on anecdotal field reports to gain a better perspective of corn and soybean production estimates.
-- Mark Weinraub is a Reuters correspondent covering grain and oilseed futures markets from Chicago. Additional reporting for Reuters by Michael Hogan in Hamburg and Naveen Thukral in Singapore.