Full explanation
Placement: band 3–5 cm beside and 3–5 cm below the seed (2×2 rule). Direct in-row placement with seed is allowed only at lower rates (≤30 kg ph.wt./ha for DAP, ≤50 kg/ha for MAP) — higher rates cause seed burn via salt index. On corn and sunflower in Ukraine, typical starter rates are 80–120 kg/ha DAP or MAP, delivering 37–62 kg P₂O₅/ha. For farms with precision planters (John Deere ExactEmerge, Väderstad Tempo, Horsch Maestro) starter is standard — skipping it costs 5–15% yield depending on spring conditions. Per Institute of Grain Crops NAAS (Dnipro) data, starter P₂O₅ on southern Ukraine chernozems boosts corn yield 8–12% and sunflower 10–15%. Trade-off: additional operation, but ROI is stable at corn price >UAH 5 500/t and P₂O₅ <UAH 55 000/t.