By Julie Ingwersen CHICAGO (Reuters) -U.S. soybean futures rose about 2% on Tuesday, buoyed by short-covering as the U.S. harvest winds down, hopes for export sales to China and uncertainty about the availability of South American supplies, traders said. Wheat futures turned higher, rallying from early declines as traders focused on uncertainty about grain shipments from the Black Sea export corridor and worries about Southern Hemisphere crops. Corn followed the firm trend. Chicago Board of Trade January soybeans settled up 28-1/4 cents at $14.47-3/4 per bushel after reaching $14.49, the contr…