This UMN Extension guide addresses iron deficiency chlorosis (IDC) in soybean, common in South Central, Southwest, West Central, and Northwest Minnesota. IDC appears as interveinal yellowing with green veins, caused by insoluble Fe(III) in high-pH, high-calcium-carbonate soils; soybean (a Type I plant) relies on root-excreted acids/reductants to convert Fe(III) to soluble Fe(II). Severity increases with high lime, wet/cold soils (bicarbonate buildup), fresh organic matter, and high soil nitrate (nitrate uptake raises leaf pH, reducing Fe reduction). Recommended management, ranked by cost-effectiveness: (1) Select an IDC-tolerant variety - the single most beneficial practice, with yield differences of up to 10 bu/acre between tolerant and susceptible varieties under high IDC pressure; (2) Seed-place an ortho-ortho EDDHA iron chelate (e.g., Soygreen) at 1-3 lb product/acre, which reliably increased yield (up to 20 bu/acre in trials) - only the o-o-EDDHA form is stable enough at high pH to be effective; other Fe products and placements gave inconsistent results; (3) Increase seeding rate, which modestly reduces IDC severity and can improve net return, especially for tolerant varieties in severe-IDC areas; (4) Use an oat companion crop (seeded ~1.5 bu/acre) to draw down soil nitrate and moisture, requiring termination by 10-12 inches height - the least beneficial of the four practices economically. Additional stress reduction (avoiding injurious herbicides, minimizing compaction, managing SCN and disease) also helps. Practices can be combined but need not all be used; growers should tailor selection to field risk and management capacity. Soil Fe tests are not useful for predicting high-lime IDC.