Nutrients

P Phosphorus
Mg Magnesium
Ca Calcium
S Sulphur
B Boron
Cu Copper
Fe Iron
Zn Zinc

Onions - Growth retardation

Symptoms
Plant growth and establishment is delayed. Rooting is adversely affected and stunted.

Reasons
Phosphorus Deficiency P is rarely required in large quantities.

Onions - Growth retardation

Symptoms
Plant growth and establishment is delayed. Rooting is adversely affected and stunted.

Reasons
Phosphorus Deficiency P is rarely required in large quantities.

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

  • Essential for energy transfer within the plant, therefore direct effect on yield and quality
  • Boosts yield and bulb size
  • Helps ensuring top yields through use of high rates of N with little quality deterioration