Nutrients

N Nitrogen
P Phosphorus
K Potassium
Mg Magnesium
Ca Calcium
S Sulphur
B Boron
Cu Copper
Fe Iron
Mn Manganese
Mo Molybdenum
Zn Zinc

Potatoes - Deformation

Symptoms
Shoots are upright and thin with dull, dark green leaves. Margins of leaves are cupped upward. Growth is stunted.

Reasons
Phosphorus deficiency (left).

Potatoes - Growth retardation

Symptoms
Lateral root development is inhibited. Tuber yield will be reduced.

Reasons
Phosphorus deficiency (right).

Potatoes - Deformation

Symptoms
Shoots are upright and thin with dull, dark green leaves. Bottom leaves show a dirty, dark blush and bend down. Stems also display a dark discoloration at the bottom. Growth is severely stunted.

Reasons
Phosphorus deficiency.

Potatoes - Deformation

Symptoms
Shoots are upright and thin with dull, dark green leaves. Bottom leaves show a dirty, dark blush and bend down. Stems also display a dark discoloration at the bottom. Growth is severely stunted.

Reasons
Phosphorus deficiency (right).

Potatoes - Discolouration

Symptoms
Shoots are upright and thin with dull, dark green leaves. Bottom leaves show a dirty, dark blush and bend down. Stems also display a dark discoloration at the bottom. Growth is severely stunted.

Reasons
Phosphorus deficiency.

Potatoes - Discolouration

Symptoms
Shoots are upright and thin with dull, dark green leaves. Bottom leaves show a dirty, dark blush and bend down. Stems also display a dark discoloration at the bottom. Growth is severely stunted.

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

  • 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 fertilizers for Phosphorus

YaraVita® HYDROPHOS™

YaraVita® HYDROPHOS™

Potatoes: To increase tuber number, 10 l/ha at tuber initiation (when 50% of 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 during tuber bulking (when the first formed tubers are greater than 10 mm in diameter). Allow 10 to 14 days between applications. Also, apply during tuber bulking following petiole analysis. Water rate: 200 l/ha. Pommes de Terre: Pour augmenter le nombre de tubercules: 10 l/ha à l'initiation des tubercules (quand 50% des stolons se sont gonflés à 2 fois leur diamètre normal juste derrière la pointe). Pour augmenter le calibre des tubercules: Au moins 2 applications de 5 l/ha pendant le grossissement (premiers tubercules 10 mm de diamètre). Laisser 10-14 jours entre traitements successifs. Appliquer aussi pendant le grossissement suite à l'analyse pétiolaire. Volume d'eau: 200 l/ha.

Read more about YaraVita® HYDROPHOS™