Zinc deficiency
A trace-element shortage that causes small, narrow, yellowing leaves bunched on short shoots, most often on alkaline or sandy soils.
Also known as: Little leaf, Rosette
Symptoms and identification
New leaves are small, narrow and yellow between the veins, and shoots stay short with leaves bunched in a rosette at the tips. Fruit trees produce poor crops and in maize the lower leaves show pale bands. Growth is slow overall.
Causes
Zinc is locked up in soil with a high pH, heavy lime or a lot of phosphorus, and is low in sandy, leached or heavily cropped soils. Cold, wet soil in spring can bring on temporary symptoms.
Organic treatment
Add plenty of compost or well-rotted manure to improve availability, and use a seaweed-based foliar feed, which contains small amounts of zinc.
Prevention
Test soil and correct high pH where possible, add compost and avoid excess phosphate fertiliser. Use a fertiliser with trace elements on poor soils.
Chemical treatment (use with care)
Spray with chelated zinc or zinc sulphate in solution, or apply zinc to the soil, at the rate on the label. Too much zinc is harmful, so do not exceed it.