Corn and wheat contracts on the CBOT closed higher on Thursday, August 20, while soybean contracts closed lower. December corn rose 5.50 cents, or 1.10%, to settle at 5.0350 dollars per bushel, after the Pro Farmer crop tour in the Midwest found that corn yields in Illinois were likely to come in below expectations. December wheat rose 2.50 cents, or 0.36%, to settle at 7.0000 dollars per bushel, as export restrictions on wheat from Russia and Ukraine led the market to expect that importing countries may have to turn to other, higher-priced sources. Wheat importers around the world are bracing for tighter supply after tit-for-tat attacks between Russia and Ukraine on ports and cargo ships in recent weeks forced several grain terminals to shut down and caused shippers to postpone or cancel dozens of cargoes during the peak export season. November soybeans fell 0.75 cents, or 0.06%, to settle at 12.3650 dollars per bushel, pressured by prospects for good US yields, weak old-crop export sales, and the likelihood of higher soybean production from Brazil.