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Liquid organic biofertilizer consortia (Bacillus/Lactobacillus/Rhizobium)

Liquid biofertilisers are stabilised suspensions of single-strain or multi-strain microorganisms maintained in cell-protecting carrier media. Compared with carrier-based powder biofertilisers (typically lignite or peat), liquid formulations have substantially better viable count, field viability and shelf life, and have become the preferred format under the FCO biofertiliser specifications.

Composition

  • Strains: Bacillus subtilis, B. megaterium, Lactobacillus, Pseudomonas fluorescens, Rhizobium, Azotobacter, Azospirillum, and consortia combining several of these.
  • Carrier: aqueous medium with cell-protectants (typically PVP, glycerol, sucrose) and sometimes preservatives.
  • Viable count: minimum 1 x 10^8 CFU/ml at expiry, as specified under FCO/NCOF liquid biofertiliser standards.
  • Shelf life: approximately 12 months under cool, dry storage.

The category is notified under FCO Schedule III liquid biofertilisers and is supported by the National Centre of Organic and Natural Farming (NCOF) and ICAR-NBAIM.

Mode of action

Each strain contributes a distinct function in the rhizosphere: nitrogen fixation (Azotobacter Biofertilizer, Rhizobium), phosphate solubilisation (PSB), potassium solubilisation (KSB), antibiotic and siderophore production for plant protection (Pseudomonas Fluorescens), and plant growth promotion through IAA and cytokinin production. Consortium products are designed so that the strains are compatible and act on complementary nutrient and disease fronts.

Target use and dose

Typical application formats:

  • Drip fertigation: 1 litre concentrate per 200 litres of irrigation water per acre.
  • Foliar spray: 5 ml per litre at vegetative and reproductive stages (for foliar-suited strains).
  • Seed treatment: 5-10 ml per kg of seed.
  • Soil drench: 1-2 litres per acre with adequate moisture.

Used across paddy, wheat, cotton, sugarcane, vegetables and orchards. Should not be tank-mixed with chemical fungicides, copper sprays or hot fertiliser slurries that kill the microbial population.

Safety and regulatory status

FCO-notified under Schedule III. Non-pathogenic to humans, animals or plants when strains are correctly identified and quality-tested. Storage at 4-25 deg C maintains viability through the rated shelf life.

See also: Microbial Biofertilizers, Azotobacter Biofertilizer, Vam Mycorrhiza, Jeevamrutham Drava, Panchagavya, Pseudomonas Fluorescens.

References

  1. BioBacter Liquid Azotobacter Biofertilizer. Office of the Principal Scientific Adviser, Government of India.
  2. Biofertilizers. ICAR Crop Science Division.