Role of Potassium in Citrus Production

Alongside nitrogen, potassium is one of the most important nutrients for citrus production. It is needed for enzyme activation, cell division, photosynthesis, photosynthate transport and osmoregulation.

Potassium effect at growth stages

Stage Potassium effect
Flowering Establish good early growth
Fruit Set Continued strong growth
Fruit Enlargement and Maturation Maximize fruit fill and fruit size, productivity, skin quality and vitamin C content and reduce granulation and fruit splitting
Post Harvest Maintain long-term fruit productivity
See more on Citrus Growth Stages.

General guidelines for Potassium application

Citrus fruit takes up more potassium than any other nutrient. Application rates can be calculated based upon leaf or soil analysis – the latter being most commonly used. Rates of 0.8-1.4lb K2O/tree are generally applied in 3-5 splits during the growing season. The main potassium uptake occurs during late fruit growth and application rates should be increased to meet this need.

Potassium deficiencies in Citrus

Visual deficiency symptoms may vary during the growing season. The first symptoms of potassium deficiency may be yellow/bronze blotches along the leaf margin. These then enlarge and join across the leaf until it is completely covered and the same yellowish color. Fruit splitting is another symptom of low potassium levels. Regular leaf tissue analysis should be taken to prevent problems occurring. Applications of potassium produce dark green, vigorous leaves.