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Sunflower
Magnesium and sulphur
| Required for: |
Yield, oil production
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| High deficiency risk: |
Mg: |
Sandy soils, high in CaCO3, large amounts of K+ and NH4+ applied
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S: |
Soils low in organic matter, temporal water shortages, poor microbial activity
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| Deficiency symptoms: |
Mg: |
Interveinal chlorosis starting at the margins of older leaves, incompletely filled flower heads
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S: |
Incompletely filled flower heads
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| Optimal leaf concentrations |
Mg: |
0.31-1.20% |
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S: |
0.50-0.60% |
| Recommendations: |
For yields of 4 t/ha, 200 - 250 kg Kieserite/ha as maintenance dressing (fertility class C soil) are recommended. Larger amounts are required for Mg poor soils and where the danger of losses through leaching are high. In areas prone to Al toxicity twice the normal rates are required. |
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Interveinal chlorosis starting at the margins of older leaves are typical for Mg deficiency.
Full seed formation requires adequate Mg and S supply.
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