Zinc Deficiency in Cotton: Symptoms and Correction
Cotton is moderately sensitive to zinc deficiency, and the early signs are easy to miss if you're not looking for them: shortened internodes that give the plant a bunched, rosette-like appearance, along with small, narrow leaves that develop interveinal yellowing or bronze mottling.
Left uncorrected through the vegetative stage, zinc-deficient cotton typically shows delayed flowering, reduced boll set, and smaller boll size at harvest — losses that are far more costly to recover from than the price of a timely zinc application.
A soil application of zinc sulphate — Agro Gold (21% Zn), Saffaron (27% Zn), or Commander (33% Zn) — worked in ahead of sowing is the standard preventive approach on fields with a known history of deficiency, particularly on the sandy and alkaline soils common across cotton-growing belts of Punjab and Sindh.
Where symptoms appear mid-season despite a soil program, a foliar spray of dissolved zinc sulphate or liquid zinc (Scotch, 10% Zn) can green up the crop faster than waiting for a second soil application to take effect, though it works best as a supplement to — not a replacement for — proper soil-applied zinc.