Oilseed Rape - Chlorosis
Symptoms
Before specific symptoms occur, potassium deficiency causes growth and yield depressions of the plants. Younger leaves remain smaller, and later, growth of the plants is stopped. Specific deficiency symptoms occur on medium/older leaves first. They show chlorotic zones on the leaf margins which become necrotic later. The younger leaves get a blue-green colour.
Causes
Potassium deficiency
Mg deficiency also shows chlorosis and necrosis on older leaves, but these start from the middle part of the leaf whereas K deficiency symptoms occur on the leaf margins first.
Oilseed Rape - Chlorosis
Symptoms
Specific deficiency symptoms occur on medium/older leaves first. Starting from the leaf margin, chlorosis spreads over the leaf blade. Later on, the chlorotic zones along the leaf margins become necrotic.
Causes
Potassium deficiency
Mg deficiency also shows chlorosis and necrosis on older leaves, but these start from the middle part of the leaf whereas K deficiency symptoms occur on the leaf margins first.
Oilseed Rape - Chlorosis
Symptoms
Before specific symptoms occur, potassium deficiency causes growth and yield depressions of the plants. Younger leaves remain smaller, and later, growth of the plants is stopped.
Specific deficiency symptoms occur on medium/older leaves first.
Starting from the marginal area, the leaves become chlorotic and subsequently show necrotic spots and patches. The necrotic tissue can show a pale, light brown colour, similar to sun burn damage.
Causes
Potassium deficiency
Mg deficiency also shows chlorosis and necrosis on older leaves, but these start from the middle part of the leaf whereas K deficiency symptoms occur on the leaf margins first.
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 crop development
- Improved resistance to stress (e
- g
- drought, cold weather etc)
- Improved disease resistance
- Increased yield
Yara recommended fertilisers for Potassium deficiency
YaraVita FOLIAR POTASH
Oilseed Rape: 5 l/ha at the 4 to 6 leaf stage. Repeat as required for moderate to severe deficiency at 7 to 14 day intervals, up to the green bud stage. Do not apply during flowering. Water rate: 200 l/ha.
Read more about YaraVita FOLIAR POTASHYaraVita MAGPHOS K
Oilseed Rape: For a single application, 5 l/ha at onset of stem extension. For moderate deficiency, 5 l/ha at 4 to 6 leaf stage and at onset of stem extension. An extra application can be made 10 to 14 days later for severe deficiency. Water rate: 200 l/ha
Read more about YaraVita MAGPHOS K