(Recasts, adds fresh quotes, pvs SYDNEY)
By Agnieszka Flak
MILAN Nov 4 (Reuters) - U.S. corn futures fell on Monday, on course for a fourth straight session of declines and the longest slide in more than three months, weighed by expectations a report this week will confirm the United States is headed for a bumper harvest.
Chicago Board of Trade December corn futures fell 0.06 percent to $4.27 a bushel by 1154 GMT, having slid 0.2 percent on Friday when the grain hit a three-year low of $4.25-3/4.
Soybeans rose for the first time in three sessions, while wheat also edged higher.
"Everyone is expecting the USDA (U.S. Department of Agriculture) on Friday to increase its forecast for the soybeans and the corn harvests," said Michaela Kuhl, a grains analyst with Commerzbank.
"All the estimates have come in quite high so everyone is expecting very good numbers. Unless there are any news to the contrary, it will be very difficult for corn prices to increase over the next few days."
Analysts said soybeans were drawing support from improved crushing margins, with Chinese interest underpinning gains.
According to preliminary results of a Reuters poll, nearly every analyst is pegging this season's U.S. corn crop at 13.8 billion bushels or higher, with several expecting it to be above 14.0 billion.
That would beat the record crop of 13.1 billion bushels four years ago.
Trade sources said Informa Economics had on Friday pegged 2013 U.S. corn production at 14.223 billion bushels, up from its previous forecast of 14.010 billion.
A USDA attache in China forecast Chinese corn production of 210 million tonnes in the 2013/14 marketing season, 1 million tonnes lower than the last official USDA estimate but still a record crop.
Corn prices were also pressured by an improved production outlook in Argentina, where heavy rain brought relief last week after dry fields had threatened crop planting.
January soybeans rose 0.36 percent to $12.56 a bushel, having closed down 1.2 percent on Friday.
Soybean export sales for 2013/14 had reached 4.7 million tonnes, topping estimates, the USDA said. China, the world's largest buyer of soybeans, bought nearly half of the soy, some 2.1 million tonnes.
December wheat was 0.37 percent higher at $6.70-1/4 a bushel, supported by healthy demand, traders said.
Saudi Arabia bought 720,000 tonnes of hard wheat in a tender for shipment between January and March, the Grain Silos and Flour Mills Organisation said on Monday.
Tunisia's state grains agency purchased 92,000 tonnes of soft wheat in an international tender which closed on Friday, European traders said.
The benchmark January milling wheat contract on the Paris-based Euronext market slid 0.12 percent to 204.50 euros ($280) a tonne, with pressure from U.S. prices outweighing healthy export demand and a weak euro against the dollar. ($1 = 0.7414 euros) (Additional reporting by Colin Packham in Sydney; Editing by Anthony Barker)