COMPOSITION OF ORGANIC FERTILIZERS

 

Organic fertilizers are derived from plant, animal, or microbial sources and supply nutrients naturally to plants while improving soil structure and fertility.

1. Primary Nutrients (Macronutrients)

Organic fertilizers supply the essential macronutrients required for plant growth:

1. Nitrogen (N)

   • Promotes leaf and stem growth

   • Sources: composted manure, blood meal, fish meal, green manure

2. Phosphorus (P₂O₅)

   • Supports root development and flowering/fruiting

   • Sources: bone meal, rock phosphate, guano

3. Potassium (K₂O)

   • Enhances disease resistance, water regulation, and fruit quality

   • Sources: wood ash, kelp meal, composted plant residues

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2. Secondary Nutrients

Organic fertilizers may also supply important secondary nutrients:

• Calcium (Ca): strengthens cell walls; sources: lime, gypsum

• Magnesium (Mg): essential for chlorophyll formation; sources: dolomite, compost

• Sulfur (S): needed for protein synthesis; sources: gypsum, elemental sulfur

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3. Micronutrients (Trace Elements)

Some organic fertilizers provide trace elements in small amounts:

• Iron (Fe) – chlorophyll synthesis

• Manganese (Mn) – enzyme activation

• Zinc (Zn) – growth regulation

• Copper (Cu) – enzymatic activity

• Boron (B) – flowering and fruiting

• Molybdenum (Mo) – nitrogen fixation

Sources include manure, seaweed extracts, bone meal, and composted plant material.

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4. Organic Matter

• Improves soil structure, aeration, and water retention

• Enhances microbial activity and nutrient cycling

• Sources: compost, humic substances, vermicompost, plant residues

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5. Beneficial Microorganisms (Optional)

• Some organic fertilizers contain microbial inoculants for soil health:

  • Nitrogen-fixing bacteria (Rhizobium)

  • Phosphate-solubilizing bacteria

  • Mycorrhizal fungi

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6. Typical Composition Ranges

Note: The exact composition varies based on source material and processing method.

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Organic fertilizers provide nutrients gradually, enhance soil fertility, and improve plant growth, making them essential for sustainable agriculture.