GRAINS-Soybeans rise ahead of U.S. sowings estimates, wheat and corn fall

HAMBURG, March 31 (Reuters) - Chicago soybeans rose on Monday, ahead of new estimates of U.S. plantings due later in the day which are expected to show a reduction in soybean sowings.

Wheat and corn were little changed, down slightly ahead of the U.S. sowing inventory estimates, with traders also concerned about the impact of U.S. import tariffs expected later this week.

Chicago Board of Trade's most-active soybeans Sv1 rose 0.5% to $10.28-1/4 a bushel at 1135 GMT.

Wheat Wv1 fell 0.09% to $5.27-3/4 a bushel, and corn Cv1 fell 0.06% to $4.53-1/2 a bushel.

The U.S. Department of Agriculture estimates of prospective plantings and quarterly grain stocks are scheduled for release on Monday at 1600 GMT.

Analysts polled by Reuters expect an increase in U.S. corn and wheat plantings but a reduction in soybean sowings.

"Corn, soybeans and wheat are seeing some bargain buying and positioning ahead of the USDA's U.S. plantings and inventories estimates later today," said Matt Ammermann, StoneX commodity risk manager. "There is also concern about the U.S. import tariffs set to be imposed later this week, with U.S. farm products vulnerable to retaliation by other countries."

"Markets have been expecting U.S. corn plantings of around 94 million acres and soybeans about 84 million acres. There could be price-supportive market relief if the USDA does not estimate U.S. sowings well over these levels, while the U.S. inventory estimates traditionally can cause market turbulence."

Rain forecast this week in parts of the U.S. and Russian wheat belts as well as expectations of smoother exports from Russia and Ukraine due to the U.S.-backed ceasefire deal also depressed wheat.

"U.S. wheat is currently looking about the cheapest in the world and there has been hope of U.S. wheat export sales to non-traditional markets, but demand is currently very weak," Ammermann said.