CHICAGO, Dec. 22 (Xinhua) -- Chicago Board of Trade (CBOT) grains closed mixed on Friday, with soybean futures edging higher for the first time in seven sessions in a short-covering bounce.

Corn was slightly higher on short-covering ahead of the Christmas holiday weekend, while wheat slipped as investors banked profits after the market scaled to two-week highs.

The most active corn contract for March delivery went up 0.75 cent, or 0.21 percent, to 3.52 dollars per bushel. March wheat delivery fell 2.25 cents, or 0.53 percent, to 4.2475 dollars per bushel. March soybeans added 1.25 cents, or 0.13 percent to 9.6025 dollars per bushel.

CBOT brokers estimate that funds have bought 4,100 contracts of corn and 1,900 contracts of wheat, while selling 3,800 contracts of soybeans. Fund traders have come out of long soybean versus short grain spreads, and are now entering a net short soybeans position.

The U.S. Department of Agriculture (USDA) on Friday announced fresh demand news for soybeans. Private exporters reported to USDA export sales of 252,000 tonnes of soybeans for delivery to China during the 2017/2018 marketing year, which began Sept.1.