Grapevines - Number reduced
Symptoms
P deficiency reduces fertility and fruit setting considerously, resulting in poor yield.
Causes
Phosphorus deficiency
Grapevines - Discolouration
Symptoms
P deficiency results in reduced growth and dark green leaves, often with some bronzing to purple lesions on the leaf blades. Discoloration starts at the margins and spreads over the interveinal areas.
The leaves become hard and stiff.
Dormant buds contain only small flower primordia what reduces the performance of the vines.
Causes
Phosphorus deficiency
Phosphorus deficiency occurs rather seldom in the fields.
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
- Healthy green foliage
- Improved fruit set
- Improved quality
Yara recommended fertilisers for Phosphorus deficiency
YaraVita FOLIAR POTASH
Grapevines (Wine Grapes only): 3 to 5 l/ha at fruit set, pea-sized berries and first colour softening. Water rate: 200 to 500 l/ha.
Read more about YaraVita FOLIAR POTASHYaraVita SENIPHOS
Grapevines: 10 l/ha at fruit set and repeated 2-3 times at 10-14 day intervals. Water rate: 500 l/ha.
Read more about YaraVita SENIPHOS
