Soybean futures decreased for the first time in a four-day period on Thursday amid speculation that falling supplies in the U.S. will reduce processing activities and boost South American imports. July Soybean futures dropped by 0.4% to $13.845 a bushel as of 11:25 a.m. on the Chicago Board of Trade after the price advanced as much as 0.8% to $14.005 a bushel.