Zinc Deficiency in Cereals Control

Symptoms

In maize a broad pale yellow or whitish band appears on each side of the midrib of the younger upper leaves while the midrib and leaf margins stay green, a condition often called white bud. In wheat the middle of younger leaves shows pale yellow patches that may turn brownish, with shortened internodes giving a stunted bushy look. New growth is most affected because zinc is less mobile in the plant.

Damage

Zinc deficiency is very widespread in Indian cereal soils, especially in alkaline and calcareous soils, sandy soils and intensively cropped rice wheat areas. It reduces tillering, delays flowering, causes poor grain set and shrivelled grain, and can cut yield substantially while also lowering the nutritional zinc content of the grain.

Organic & cultural control

Add well rotted farmyard manure and compost regularly because organic matter improves the availability of zinc in the soil and supplies a small amount itself. Avoid over liming and keep the soil from staying continuously waterlogged, since both reduce zinc availability. Good organic matter management combined with a soil test helps prevent recurring deficiency.

Chemical control

Where soil test shows low zinc, apply zinc sulphate to the soil at the recommended rate at sowing, and for a standing crop showing symptoms give a foliar spray of about half a percent zinc sulphate solution, with a little lime added if using the heptahydrate form, repeated as needed. Always follow recommended rates and consult your KVK or agronomist and a soil test for the correct dose and method.

Always follow the product label, the recommended pre-harvest interval, and your local KVK or agronomist. Pesticide approvals change, so verify before use.

Prevention

Get the soil tested for zinc and apply zinc sulphate to the soil once every two to three years as recommended, as the effect lasts more than one season. Keep adding organic manure, avoid excess phosphorus and over liming which lock up zinc, and grow zinc efficient varieties where available. In rice wheat systems pay special attention as these soils often run low in zinc.