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
Edges and tips of the lower leaves become yellow and later necrotic. Eventually, the marginal yellowing spreads between the veins as the deficiency progresses. Leave margins curl up. The leaves often wither and collapse prematurely. Plant growth is squat and stunted.

Reasons
Potassium deficiency

Potatoes - Discolouration

Symptoms
Potassium deficient tubers show black spots. When cut, they blacken rapidly. The spots mostly occur near the vascular ring at the stolon end of the tuber.

Reasons
Black spot due to potassium deficiency

Potatoes - Deformation

Symptoms
Edges and tips of the lower leaves become yellow and later necrotic. Eventually, the marginal yellowing spreads between the veins as the deficiency progresses. Leave margins curl up. The leaves often wither and collapse prematurely. Plant growth is squat and stunted.

Reasons
Potassium deficiency

Potatoes - Deformation

Symptoms
Edges and tips of the lower leaves become yellow and later necrotic. Eventually, the marginal yellowing spreads between the veins as the deficiency progresses. Leave margins curl up. The leaves often wither and collapse prematurely. Plant growth is squat and stunted.

Reasons
Potassium deficiency

Potassium deficiency made worse by

  • Acidic soils (low pH)
  • Sandy or light soils (leaching)
  • Drought conditions
  • High rainfall (leaching)
  • or heavy irrigation
  • Heavy clay (illite) soils
  • Soils with low K reserves
  • Magnesium rich soils

Potassium is important for

  • Improved yield and quality
  • Increased tuber size
  • Improved disease resistance

Yara recommended fertilizers for Potassium

YaraVita CROP BOOST

YaraVita CROP BOOST

Potatoes: To stimulate early growth: 10 l/ha one week after 100 percent crop emergence. To increase tuber number: 10 l/ha at tuber initiation (when 50 percent at 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 during tuber bulking ( as soon as first formed tubers are 10 mm in diameter) and following petiole analysis during tuber bulking. Allow 10 to 14 days between applications. Water rate: 200 l/ha.

Read more about YaraVita CROP BOOST