Potatoes - Deformation
Symptoms
Shoots are upright and thin with dull, dark green leaves. Margins of leaves are cupped upward.
Growth is stunted.
Causes
Phosphorus deficiency (left)
Potatoes - Growth retardation
Symptoms
Lateral root development is inhibited. Tuber yield will be reduced.
Causes
Phosphorus deficiency (right)
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
- Increased number of tubers
- Produces tubers of uniform size
- Boosts bulking and increases the yield of tubers
- Increases tuber dry matter content and starch levels
- Improves storage potential of tubers and reduces storage diseases
Yara recommended fertilisers for Phosphorus deficiency
YaraVita MAGPHOS K
Potatoes: To increase tuber number, 10 l/ha at tuber initiation (when 50% of the tip swellings are twice the diameter of the rest of the stolon). To increase tuber size a minimum of 2 applications of 5 l/ha or 1 to 2 applications of 10 l/ha during tuber bulking (as soon as first formed tubers are 10 mm in diameter). Allow 10-14 days between applications. Water rate: 200 l/ha
Read more about YaraVita MAGPHOS KYaraVita SENIPHOS
Potatoes: Apply Seniphos at 15 l/ha in 200 litres of water, at the onset of tuber initiation. The application may be repeated at bulking, using 5 l/ha in 200 litres of water repeated at 2-3 week intervals.
Read more about YaraVita SENIPHOS
