CANBERRA, March 26 (Reuters) - Chicago wheat futures rose on Tuesday and were trading near a three-week high, supported by concerns that exports from top supplier Russia could be disrupted by a dispute between shippers and regulators over grain quality.
Soybean and corn futures fell ahead of a U.S. Department of Agriculture (USDA) planting intentions report due on Thursday that could move the markets.
FUNDAMENTALS
* The most-active wheat contract on the Chicago Board of Trade (CBOT) was up 0.3% at $5.56-1/2 a bushel by 0004 GMT after reaching $5.67 on Monday, its highest since March 4.
* CBOT soybeans were down 0.3% at $12.06-1/4 a bushel and corn fell 0.2% to $4.37 a bushel.
* All three contracts are near their lowest levels since 2020 amid plentiful supply and speculators are betting on further price falls. Wheat fell as low as $5.23-1/2 this month.
* Russian authorities are preventing the processing and shipment of about 400,000 metric tons of grains, the owner of one of Russia's largest grain exporters, TD RIF, said.
* Authorities say their action follows complaints from importing countries about the non-compliance of Russian grain quality with quarantine requirements.
* Traders were already concerned about the impact on Ukrainian wheat exports of Russian attacks on Ukraine's port and energy infrastructure.
* Meanwhile, winter grain crops are in mediocre condition in large parts of the European Union, EU crop monitoring service MARS said.
* However, huge supply from Russia - the biggest exporter - has driven down wheat prices and analysts predict that shipments could set a new March record of 5 million tons this month.
* Elsewhere, consultants AgRural said Brazil's 2023/24 soybean harvest had reached 69% of the planted area, as of last Thursday, slightly below the 70% seen at the same time a year earlier.
* Traders are waiting for a USDA planting intentions report due on Thursday, with analysts predicting an increase in soybean area and declines in corn and wheat area.
MARKETS NEWS
* U.S. stocks lost ground at the start of a holiday-shortened week on Monday as investors positioned themselves ahead of inflation data.
(Reporting by Peter Hobson; Editing by Sherry Jacob-Phillips)
