Calcium magnesium and manganese
Magnesium
- Mg deficiency usually occurs on sandy acid soils.
- High rates of K-fertilizers accentuate Mg- deficiency.
- In situations where Mg-deficiency is expected, K-fertilizer such as potassium magnesium sulphate and dolomite limestone is used.
- A foliar application of a 2% solution of MgSO4 is used.
Deficiency symptoms: Magnesium
- - Symptoms appear first on young mature leaves
- - General chlorosis with veines remaining green
- - Leaflets near growing point remain green
- - Interveinal nesrosis
Magnesium 1------Magnesium 2------Magnesium 3
Calcium
- Ca deficiency mostly occurs on sandy soils with a low pH.
- Transport of Ca within the plant and in sprouts is poor.
- Seed tuber from Ca-deficient plants produce sprouts that become necrotic a few mm below the tip, the sprouts start branching and germination of the crop is delayed.
- Seed can be treated with calcium sulphate.
Manganese
Usually the youngest leaves of a potato crop will show the first signs of a manganese deficiency.
The top leaves will turn slightly pale, fold inwards and become a little limp.
A few days later rows of numerous black dots will appear, mainly along the main veins.
Manganese 1------Manganese 2