Chicago Board of Trade (CBOT) grains futures closed mixed on Tuesday with May soybean delivery falling below 10 dollars per bushel.

The most active corn contract for May delivery rose 1.25 cent, or 0.35 percent, to 3.6225 dollars per bushel. May wheat delivery settled unchanged at 4.305 dollars per bushel. May soybeans dropped 6.75 cents, or 0.67 percent, to 9.9925 dollars per bushel.

It's the first time since January 6 that soybean futures dropped below the ten-dollar-per-bushel mark amid expectations that overseas buyers would turn to Brazil and Argentina from the U.S. to meet their supply needs.

The U.S. Department of Agriculture last week raised its projection for Brazilian soybean output to 108 million metric tons from 104 million.

Corn seemed to have found support on export demand, following consecutive decline in the past six trading days. China has reportedly secured three cargoes of U.S. corn, with talk that the top Asian buyer may be in the market for 500,000 metric tons.

Wheat closed flat, but snow storm and cold temperatures this week might threaten winter wheat in the U.S. Midwest.