Fertilizer Materials and Their Composition
Fertilizers are materials applied to soil or plants to supply essential nutrients. They can be organic, inorganic, or liquid.
Classification of Fertilizer Materials
- Based on Nutrient Source
Nitrogenous Fertilizers: Supply N for vegetative growth, chlorophyll formation, protein synthesis.
Examples & Composition:
|
Fertilizer |
N % |
|
Urea |
46% |
|
Ammonium Sulphate (AS) |
21% |
|
Calcium Ammonium Nitrate (CAN) |
26% |
|
Ammonium Chloride |
25% |
|
Anhydrous Ammonia |
82% |
Phosphatic Fertilizers: Supply P for root development, flowering, seed formation.
Examples & Composition:
|
Fertilizer |
P₂O₅ % |
|
Single Super Phosphate (SSP) |
16–20% |
|
Triple Super Phosphate (TSP) |
45–50% |
|
Diammonium Phosphate (DAP) |
46% |
|
Rock Phosphate |
28–32% |
Potassic Fertilizers; Supply K for water relations, enzyme activation, stress tolerance.
Examples & Composition:
|
Fertilizer |
K₂O % |
|
Muriate of Potash (MOP) |
60% |
|
Sulphate of Potash (SOP) |
50% |
|
Potassium Nitrate |
46% K₂O + 13% N |
Secondary Nutrient Fertilizers: Supply Ca, Mg, S.
Examples & Composition:
|
Fertilizer |
Nutrient Content |
|
Gypsum |
Ca 23%, S 18% |
|
Dolomite |
Ca 30–32%, Mg 20–22% |
|
Kieserite |
Mg 25%, S 17% |
Micronutrient Fertilizers: Supply Zn, Fe, Cu, B, Mo.
Examples & Composition:
|
Fertilizer |
Nutrient Content |
|
Zinc Sulphate Heptahydrate (ZnSO₄·7H₂O) |
Zn 21%, S 17% |
|
Ferrous Sulphate (FeSO₄·7H₂O) |
Fe 20% |
|
Borax |
B 11–12% |
|
Sodium Molybdate |
Mo 39% |
Liquid Fertilizers
- Applied directly to soil or foliage for quick nutrient supply.
- Advantages: Rapid absorption, easy application in fertigation or foliar spray.
Common Liquid Fertilizers
|
Fertilizer |
Nutrient Content |
Uses |
|
Urea Solution |
N 30% |
Foliar spray, fertigation |
|
Ammonium Nitrate Solution |
N 20–25% |
Soil or fertigation |
|
Mono-Ammonium Phosphate (MAP) Solution |
N 12%, P₂O₅ 52% |
Fertigation |
|
Potassium Nitrate Solution |
K₂O 38%, N 13% |
Foliar / fertigation |
|
Liquid Micronutrients |
Varies (Zn, Fe, Mn, B, Cu) |
Foliar spray for deficiency correction |
Specialty Fertilizers
- Water-soluble fertilizers (NPK grade) for fertigation/hydroponics.
- Controlled-release fertilizers → coated with sulfur or polymers to reduce losses.
- Nano-fertilizers → emerging technology for precision agriculture.
Fertilizer Facts for Exam
- Urea → highest N content (46%).
- MOP → most common K fertilizer (60% K₂O).
- SSP → low P content (16–20%), TSP → high P content (45–50%).
- DAP → both N (18%) & P₂O₅ (46%).
- Liquid fertilizers are rapid acting, suitable for foliar sprays and fertigation.
