The symptoms of zinc deficiency appear after three weeks of sowing, causing bronzing of new and old leaves. The brown coloured spots extend from the leaf tip towards the base and scorching of leaves occurs on the margins. The scorched portion turns brown (Plate 1). Interveinal chlorosis in the form of golden yellow colour is observed in the middle leaves. The old and middle leaves also show upward or downward cupping tendency (Plate 2). The plants bear less fruits and opening of bolls is abnormal.

Soil application as broadcast and incorporation is the most popular method for amelioration of zinc deficiency.

Broadcast evenly 25 kg zinc sulphate per hectare prior to last ploughing followed by harrowing in the top soil. In saline-sodie soils and freshly levelled fields, the rate of application is increased to 50 kg zinc sulphate per hectare.

Two to three sprays of 0.5 per cent solution of zinc sulphate made at 7-10 days intervals can ameliorate zinc deficiency. For solution sufficient to spray one hectare crop area, mix 2.5 kg of zinc sulphate and 10 kg urea (or 1.25 kg lime) in 500 litres of water. Spraying should be done in the evening before the sunset

Response of cotton to zinc sulphate application (Plate 3) ranges from 2 to 5 quintals seed cotton per hectare. Experimental results most often show 10 per cent increase in the crop productivity with amelioration of zinc deficiency.