Micronutrients are needed in very small amounts but are essential for crop growth. Prior research in Iowa and neighboring states showed inconsistent corn and soybean grain yield responses to fertilization with micronutrients, except for zinc in corn. This report summarizes results of two studies with corn and soybean, one with application to the soil and the other with application to foliage, which were conducted at this farm from 2012 through 2014. The micronutrients evaluated were boron (B), copper (Cu), manganese (Mn), and zinc (Zn).