SPRINGFIELD — Production of Illinois’ two most valuable crops fell by roughly one-fifth last year, according to final crop yield numbers released Friday by the U.S. Department of Agriculture. Corn and soybean growers saw production drop 18.6 percent and 20.4 percent respectively compared to 2018. Farmers harvested just over 1.8 billion bushels of corn, down from more than 2.2 billion the year before.