GRAINS-Wheat soars on rumors of Russian export curbs; soy/corn firm

(Updates with closing U.S. prices) CHICAGO, Aug 29 (Reuters) - U.S. wheat futures rose 3.5 percent on Wednesday on technical buying and rumors that Russia might curb wheat exports, traders said. Soybeans and corn closed modestly higher, following wheat. Chicago Board of Trade December soft red winter wheat futures settled up 18-1/2 cents at $5.41-3/4 per bushel. CBOT November soybeans ended up 2-3/4 cents at $8.36 a bushel and December corn finished up 1/4 cent at $3.56-1/2 a bushel. Wheat jumped on talk that Russia, the world's biggest wheat supplier, might curtail exports after a disappointing harvest this summer. Russia's agriculture ministry will meet grain exporters on Sept. 3 to discuss the market situation, two trade sources told Reuters. "Wheat prices posted double-digit gains overnight on rumors that Russia may apply export taxes once shipments reach 25 million tonnes. The government has not confirmed it, but the trade is responding once again to the possibility," INTL FCStone chief commodities economist Arlan Suderman said in a note to clients. "There is a sense that the government is watching the situation closely - likely monitoring to see how the 2019 crop goes into the ground next month," Suderman added. The U.S. Department of Agriculture has projected Russia's 2018/19 wheat exports at 35 million tonnes. "If wheat exports out of Russia are under 30 (million tonnes), that's something the market is going to sit up and take notice of," said Rich Feltes, vice president for research with R.J. O'Brien. Russian consultancy IKAR on Tuesday lowered its estimate of Russia's 2018 wheat harvest to 69.6 million tonnes from 70.8 million tonnes previously. The firm left its Russian wheat export estimate unchanged at 32.5 million tonnes. Soybean futures rose on a light technical bounce after the benchmark November contract fell to $8.32, its lowest since setting a contract low of $8.26-1/4 on July 16. But prospects for a record-large U.S. harvest hung over the market. The Pro Farmer advisory service last week projected the average U.S. 2018 soybean yield at 53.0 bushels per acre, a record high if realized. "We still don't know how large these crops might be. With this great finish to our summer, are we going to go over 53 bushels, and how much? Those are 'what-ifs' that the bulls have to worry about," Feltes said. Additional pressure stemmed from fears that African swine fever in China's hog herd could limit demand for soymeal. China's agriculture ministry said it cannot rule out the possibility of new outbreaks. Meanwhile, rains in the U.S. Midwest this week could bolster corn and soy prospects, but traders were monitoring flooding in Wisconsin and potentially excessive moisture in parts of southern Minnesota and Iowa.

CBOT settlement prices:

Net Pct Volume

Last change change

CBOT wheat WZ8 541.75 18.50 3.5 115900 CBOT corn CZ8 356.50 0.25 0.1 209654 CBOT soybeans SX8 836.00 2.75 0.3 102611 CBOT soymeal SMZ8 305.20 0.50 0.2 54004 CBOT soyoil BOZ8 28.42 -0.16 -0.6 41913

NOTE: CBOT December wheat and corn and November soybeans shown in cents per bushel, December soymeal in dollars per short ton and December soyoil in cents per lb.

(Additional reporting by Naveen Thukral in Singapore; Editing