Full explanation
Signs of S deficiency on rapeseed: chlorosis of young leaves (unlike N-deficiency — old leaves), pale green-yellow upper canopy, short pods with fewer seeds per pod. On Forest-Steppe chernozems (Poltava, Cherkasy, Vinnytsia) S deficit is latent, revealed only by winter-spring soil analysis. Rapeseed S program: (1) primary autumn — AN + ammonium sulfate, 50 kg N + 30 kg S/ha; (2) 1st spring — AN or UAN-32, 50–70 kg N/ha; (3) 2nd spring (early stem extension) — AN 40–60 kg N/ha + ATS in tank mix, 20–30 kg S/ha; (4) foliar at bud stage — MgSO₄ 3–5 kg/ha + B chelate. S sources: ammonium sulfate (cheapest), polyhalite (premium for Mg + Ca), ATS (premium for liquid). Trade-off: a UAH 600–1 500/ha investment in S nutrition on 2.5–3.5 t/ha rapeseed yields ROI 300–500% — one of the most effective agronomic practices on rapeseed.