Phosphorus deficiency leads to fruits with coarse and thick peel.
Made worst by
Acidic or very alkaline (calcareaus) soils. Low organic matter. Cold or wet conditions. Crops with a poorly developed root system. Soils with low P reserves. Soils with a high phosphate capacity. Iron rich soils.
Vegetative growth increased. Leaves are much greener. Fruit set is increased. Yield boosted, fruit quality enhanced (sugar/acid improved). Particularly important in young trees with poorly developed root systems.
Phosphorus deficiency on orange (right)