CHICAGO, April 4 (Reuters) - Soybeans dropped on Thursday following lower-than-expected weekly export sales data from the U.S. Department of Agriculture (USDA), seasonally rising supplies from the South American harvest and falling soyoil prices.
Corn ended on a firm note on late-session bargain buying though weekly export sales last week fell to the lowest in almost three months, but were still in line with trade estimates.
Wheat eased after Russian grain trader Aston denied that local authorities had halted some of its exports, lessening recent concerns about slowed shipments from the world's top wheat-supplying nation.
A weaker dollar, however underpinned the market.
Traders are monitoring weather in the U.S. Midwest ahead of corn planting that is due to ramp up over the coming weeks.
While rain and snow in the central corn belt are expected to boost soil moisture reserves, there are forecasts of higher temperatures later this month that could help field work.
Soybean futures neared Wednesday's one-month low as net U.S. export sales last week were short of market expectations at 194,220 metric tons, according to weekly USDA data released on Thursday.
Analysts said a daily USDA sales announcement of 152,404 tons in additional sales to Mexico offered little support as Brazilian shipments are accelerating and as season-to-date U.S. sales remain about 19% below last year.
There also remains a lack of new-crop demand for U.S. soybeans, said Brian Splitt, co-founder of AgMarket.Net.
"The big crop out of Brazil is really preventing that from happening."
CBOT May soybeans fell 2-1/4 cents to $11.80 a bushel, while May corn rose 3-1/2 cents to $4.35-1/4 a bushel.
CBOT May wheat rose 1/4 cent to $5.56-1/4 a bushel.
In Russia, firmer prices, dry weather and reports of delays to export shipments have lent support to international wheat markets, but concerns about Russian supplies were tempered by signs that export flows remain large and Aston's denial. (Additional reporting by Gus Trompiz in Paris and Naveen Thukral in Singapore; Editing by Subhranshu Sahu, Sherry Jacob-Phillips, David Evans and David Gregorio)
