Banana - Chlorosis
Symptoms
The symptoms of phosphorus deficiency start on older leaves. The leaves show a darker, blue-green color, and yellow chlorotic zones develop in the intercostal areas from the leaf margin. Later, these zones coalesce and become necrotic with a light brown color.
Reasons
Phosphorus deficiency
Excess nitrogen fertilization also leads to a blue-green color of the leaves.
Manganese deficiency also causes marginal necrosis, but these have a darker color.
Banana - Growth retardation
Symptoms
Slow growth with thin and woody stems; petioles break easily.
Reasons
Phosphorus deficiency
Phosphorus deficiency made worse 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
Phosphorus is important for
- Part of nucleic acids, phospholipids and energy storing and transferring systems in plants
- Important for root growth, flower development and fruit set