Full explanation
Sulfate-S sources: ammonium sulfate (NH₄)₂SO₄ — 24% S, cheapest; magnesium sulfate MgSO₄·7H₂O (Epsom salt) — 13% S; potassium-magnesium sulfate K₂SO₄·MgSO₄ — 22% S; gypsum CaSO₄·2H₂O — 18% S. Elemental-S sources: ammonium thiosulfate ATS (NH₄)₂S₂O₃ — 26% S liquid form, compatible with UAN-32; granular elemental-S + bentonite (ThioGro, Sulvaris) — 85–90% S. Ukraine's S deficit is significant because atmospheric SO₂ deposition has dropped 3–4× since the 1990s, compounded by crop removal; NAAS estimates 15–25 kg S/ha deficit on Forest-Steppe chernozems. Trade-off: sulfate form works 'here and now' (critical for autumn rapeseed), elemental is prolonged and cheaper per kg S but unsuitable for emergency fixes. Recommendation: rapeseed — 60–80 kg S/ha sulfate; corn/sunflower — 20–40 kg S/ha elemental in autumn.