Research in Minnesota has shown that using boron fertilizers will improve the yield of alfalfa and vegetables on some sandy soils.
Information gathered from several research projects focused on the use of this particular nutrient.
Most Minnesota soils contain adequate amounts. However, small grains grown in organic and peat soils are exceptions.
Fe (iron) is required by several enzymes involved in the formation of chlorophyll.
IDC Management in Soybeans: Research from Large Plot Trials (5.9 MB PDF) — Institute of Ag Professionals, University of Minnesota Extension
Are micronutrients needed in high yield environments? (420 K PDF) — University of Minnesota Extension