Nutrient Composition and Biochemical Role
Under the Fertilizer Control Order (FCO), agricultural Magnesium Sulphate is formulated as soluble crystalline granules or powder.
Magnesium is the central metallic atom of the chlorophyll molecule; without adequate magnesium, plants cannot capture solar energy for photosynthesis.
Sulfur acts synergistically to drive protein synthesis and enzyme formation, making MgSO4 an essential dual-nutrient supplement.
- Magnesium (Mg): Central building block of chlorophyll and cofactor for hundreds of cellular enzymes
- Sulfur (S): Drives synthesis of sulfur-containing amino acids (methionine, cysteine) and oils
- 100% water solubility: Dissolves cleanly without sediment, making it ideal for foliar spraying and fertigation
Deficiency Symptoms and Target Crops
Magnesium deficiency displays as prominent interveinal chlorosis on older lower leaves, where leaf veins remain dark green while interveinal areas turn yellow, bronze, or reddish.
It is widely applied in intensive cash crops, fruit orchards, and vegetables cultivated under high potassium or ammonium fertilization, which restricts magnesium uptake.
- Cotton and pulses: Prevents leaf reddening and premature lower leaf drop
- Tomatoes and vegetables: Eliminates interveinal yellowing, supporting sustained fruit sizing
- Fruit orchards: Prevents leaf scorch and promotes uniform fruit maturity in citrus, banana, and grapes
Application Guidelines: Fertigation, Foliar Spray, and Soil
MgSO4 can be broadcast into soil during basal field preparation, injected through micro-irrigation lines, or applied as a foliar mist.
Foliar feeding delivers immediate corrective therapy when high soil potassium blocks root magnesium absorption.
- Drip fertigation: Injected through drip tanks at recommended concentrations per irrigation cycle
- Foliar spray: Dissolve in clean water and spray evenly across foliage upon noticing early interveinal yellowing
- Compatibility: Compatible with most soluble fertilizers; avoid mixing with highly concentrated phosphates in concentrated stock tanks
Official source
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Department of Fertilizers - IFMS Portal ↗Related on KisanPe
Common questions
What are the primary nutrients supplied by Magnesium Sulphate?
Magnesium Sulphate supplies two essential secondary plant nutrients: magnesium (approximately 9.6%) and sulfur (approximately 12%).
What does magnesium deficiency look like in crops?
It appears as interveinal chlorosis on older lower leaves, where veins remain green while the tissue between veins turns yellow, bronze, or purple.
Can Magnesium Sulphate be sprayed on crop leaves?
Yes, its complete water solubility allows rapid foliar absorption to correct acute magnesium deficiency quickly.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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