Nutrients

N Nitrogen
P Phosphorus
K Potassium
Mg Magnesium
Ca Calcium
S Sulfur
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

YaraMila® 15-15-15

YaraMila® 15-15-15

Potatoes: General rates of 100-150 lbs of 15-15-15 per acre as a portion of the end NPK requirements. Complement with your N and K applications to meet the remaining needs. YaraMila 15-15-15 is a sulfate of potash based fertilizer, which provides sulfur and helps with quality of tubers. Rates may vary with location, variety and potential yields, consult your local agronomist for further details.

Read more about YaraMila® 15-15-15

YaraVita® MAGPHOS™

YaraVita® MAGPHOS™

Potatoes: To increase tuber size: A minimum of 2 applications of 1-2 quarts/acre during tuber bulking (as soon as first formed tuber are ½" in diameter) and following petiole analysis during tuber bulking. Allow 10 to 14 days between applications. Water rate: 5 to 20 gallons/acre.

Read more about YaraVita® MAGPHOS™

YaraVita® PHOZTRAC™

YaraVita® PHOZTRAC™

Potatoes: 2-4 quarts/acre 1 week after 100% crop emergence. Repeat as necessary at 10 to 14 day intervals. Water rate: 3 to 25 gallons/acre.

Read more about YaraVita® PHOZTRAC™

YaraVita® SENIPHOS™

YaraVita® SENIPHOS™

Potatoes: A minimum of 2 applications of 2 to 4 quarts/acre during tuber bulking (as soon as first formed tubers are ½" in diameter) and following petiole analysis during tuber bulking. Allow 10 to 14 days between applications. Water rate: 20 gallons/acre.

Read more about YaraVita® SENIPHOS™