(recasts, updates with closing prices)
By Mark Weinraub
CHICAGO, May 2 (Reuters) - U.S. soybean futures fell on Wednesday on concerns about decreased export demand from China as well as rising expectations for a bumper crop in Brazil, traders said.
Wheat futures were mixed. Soft red winter wheat offerings eased after a rally on Tuesday while hard red winter wheat contracts rose due to worries about the drought-stressed crop in the U.S. Plains.
Corn futures were close to unchanged but closed in negative territory. The yellow grain was underpinned by the slow start to planting in the U.S. Midwest but traders were reluctant to push prices past the 9-1/2-month top hit during the session.
The United States is sending a top-level trade delegation to China this week but the market was discounting hopes of an agreement between the two countries.
"Most of the China watchers do not think they are going to come up with any breakthroughs," said Jim Gerlach, president of A/C Trading. "There is some nervousness in the soybean market."
Chicago Board of Trade July soybean futures dropped 10-1/4 cents at $10.43 a bushel.
U.S. soybean export sales to China have come to a halt, the chief executive of agricultural merchant Bunge Ltd said on Wednesday, over mounting trade tensions between the world's top two economies.
Additionally, INTL FCStone raised its estimate of soybean production in Brazil, the top supplier to China, to 117.0 million tonnes.
CBOT July soft red winter wheat futures dropped 2-1/2 cents to $5.26-3/4 a bushel while K.C. July hard red winter wheat was up 2-1/4 cents at $5.55-1/4 a bushel, with the most-active contract peaking at its highest since July 10.
Yield potential for hard red winter wheat in southwest Kansas and northwestern Oklahoma is roughly half that of a year ago as exceptional drought conditions take a toll on the crop, scouts on the Wheat Quality Council's annual tour said on Wednesday.
"First results of the crop tour are not positive," said Matt Ammermann, commodity risk manager with INTL FCStone. "There is also concern about dryness in Black Sea and Australia, so there is lots of dryness talk."
CBOT July corn was down 3/4 cent at $4.05 a bushel.
"For U.S. plantings, there is a lot of focus on the date May 15 as an important deadline for U.S. corn to be sown, Ammermann said. "Corn sown after May 15 could have lower yields." (Additional Reporting by Michael Hogan in Hamburg; editing by Jonathan Oatis and Bill Trott)