Feb 29, 2016 Illinois State Average Soybean Yields Reported Illinois State Average Soybean Yields Reported Illinois State Average Soybean Yields Reported 2015 average soybean harvest yields were reported this week. Overall harvest numbers remained strong, despite weather challenges. Statewide, fields produced an average of 56 bushels per acre. Take a moment to compare your harvest yields to county and state averages, as you plan your land strategy for the coming year. -LT Taylor