(Updates with closing prices)
By Mark Weinraub
CHICAGO, June 28 (Reuters) - Chicago Board of Trade soybean futures rose 1.3 percent on Tuesday to a one-week high, on concerns about crop development in the U.S. Midwest and signs of good export demand, traders said.
Corn futures were mostly steady, with traders locking in profits after weather concerns pushed prices to a one-week high early in the session.
Wheat futures also closed lower, with the K.C. hard red winter wheat contract carving out a fresh 10-year low and notching its fourth straight decline. Traders said harvest pressure and ample global supplies kept a bearish tone on the market.
CBOT November soybean futures, the most actively traded contract, settled up 15-1/2 cents at $11.20-1/4 a bushel. The front-month July contract was 17-1/2 cents higher at $11.50-1/2 a bushel.
"Both supply and demand support are in play helping both old and new crop contracts break out of their three-week declines," said Bryce Knorr, senior grain market analyst at Farm Futures.
The U.S. Agriculture Department on Monday afternoon said the soybean crop was rated 72 percent good to excellent, down 1 percentage point from a week earlier. USDA also reported that exporters sold 150,000 tonnes of U.S soybeans for delivery to unknown destinations.
A falling dollar also helped to bolster the export prospects for U.S. soybeans.
CBOT December corn settled unchanged at $3.94-1/4 a bushel. The July contract also was flat, at $3.85 a bushel. Other corn contracts posted modest declines.
Weather concerns supported corn early in the session.
The European forecast model predicted highs for parts of the Midwest near 100 degrees Fahrenheit (38 Celsius) late next week as the crop begins pollinating. Corn pollinating under the stress of high temperatures often shows severe yield reductions at harvest.
CBOT September soft red winter wheat futures was 1 cent lower at $4.57-1/4 a bushel. CBOT July wheat shed 3 cents to $4.43-3/4 a bushel. (Additional reporting by Naveen Thukral in Singapore, Michael Hogan in Hamburg and Nigel Hunt in London; Editing by James Dalgleish and David Gregorio)