Bio-fertilizers for Paddy (Rice)

Bio-fertilizers are a group of biological product. Biofertilizers contain nutrient providing beneficial microorganisms. Know about the beneficial microorganisms and important bio-fertilizers for paddy (rice) plants.

Index: Bio-fertilizers for Paddy (Rice)

(1). Lists or Bio-fertilizers of paddy plants.
(2). Blue Green Algae: Basic information, importance, commercially available products, use.
(3). Azospirillum: Basic information, importance, commercially available products, use.
(4). Phosphorus Solubilizing Bacteria (PSB ): Basic information, importance, commercially available products, use.
(5). Care.
(6). Frequently asked questions.

Also read: Major insect-pests of rice

Effect of organic manures on rice plants

(1). Lists or Bio-fertilizers of paddy plants

  • Blue Green Algae (BGA).
  • Azospirillum.
  • Phosphorus Solubilizing Bacteria (PSB).

(2). Blue Green Algae (BGA) for rice

2.1 About Blue Green Algae

The Blue Green Algae or BGA is one of the most important bio-fertilizer used in rice of paddy field. It fixes nitrogen in paddy fields.

It is a cyanobacteria. It is known for its  photosynthesis activity. And due to their photosynthetic ability they can fix atosphoric nitrogen into soil ecosystem.


The BGA provides 25 kg nitrogen in one hectare of paddy filed.
It also fixes 10 kg of organic matter in one hectare of paddy field.

Also read: Minor insect-pests of rice

2.2 Genus of blue green algae:

  • Anabaena.
  • Nostoc.
  • Rivularia.
  • Calothrix.
  • Scytonema.


Known for: Symbiotic relation with some species of fern.

Species of anabaena (heterocyst forming)

  • Anabaena circinalis
  • Anabaena variabilis

Known for excellent nitrogen fixing.

Anabaena azollae

  • It is of commercial importance.
  • A. azollae forms a symbiotic relation with azolla to fix atmospheric nitrogen into soil.

2.2.2 Nostoc

Presence: Soil, moist rocks, lakes etc.

Species of nostoc (nitrogen fixing nostoc)

  • Nostoc commune.
  • Known as star jelly.
  • It produces heterocyst cells.

Nostoc punctiforme

  • Forms heterocysts under nutrient limiting conditions.
  • They make a symbiotic association with the water fern azolla.

Nostoc thermotolerans

It is a new strain of BGA.

Nostoc verrucosum

It can tolerate extreme environmental conditions.

2.2.3 Rivularia

Presence: Damp soil, submerged stones, moist rocks.

Some species

  • R. multifida.
  • R. rubra.
  • R. vermiculata.

2.2.4 Calothrix

Habitat: Fresh water.
Family: Rivulariaceae.

2.2.5 Scytonema

Habits: Soil, wood, rocks, plants.
Association: Some species form a symbiotic relationship with fungi.

The species (described above) form more numbers of heterocyst cells.

The species of blue green algae which have more heterocyst cell, will fix much amount of environmental N in paddy fields.

Also read: Introduction to major insect-pests of maize

2.3 Technique of the culture of  Blue Green Algae in paddy fields:

2.3.1 Application of phosphorus

Apply full amount of phosphorus at the time of transplanting.

2.3.2 Amount of water in paddy fields

A paddy field should have atleast 5 – 8 cm height of stagnant water (water column), and it is recommended.

2.3.3 Application ofPSB culture

Apply the BGA (Blue Green Algae) culture in the paddy field 6 – 10 days after transplanting the paddy plant in fields by using spraying method.

Mix 10 kg of BGA culture with 25 kg of crumbly soil or dry FYM before its application.

2.3.4 Application of Nitrogen

A nitrogenous fertilizer such as urea is used 20 days after the application of Blue Green Algae.

2.3.5 Control of the harmful green algae

Testing the harmful green algae: Use the solution of iodine or tincher iodine (tincher iodine from a medic store) to identify harmful green algae.

  • Change in colour:
  • Blue.
  • Black.
  • No change in colour.

Blue colour of the algae: Dissolve 75 g of copper sulphate in 150 l of water and spray it over the BGA culture in paddy fields. If necessary, repeat it in the next 7 days.

No change in colour: There is no need of any chemical treatment.

Note: The population of harmful green algae should be managed at its initial growth stage.

Black colour of the algae: Dissolve 75 g of copper sulphate in 150 l of water and spray it over the BGA culture in paddy fields. If necessary, repeat it in the next 7 days.

Also read: Entomology multiple choice questions

(3). Azospirillum for rice

3.1 About azospirillum

It is an asymptotic free living soil bacterium which also fixes environmental nitrogen. It is a genus of bacteria.

By 2020, there are 21 species of azospirilluum.

Type: Bacteria (diazotrops)
Family: Rhodospirillaceae
Habitat: Fresh water and soil.

Azospyrillum is ideal for water logging conditions, and the soil with high moisture content.

Research suggests that azospyrillum can increase rice production up to 3 to 8 percent.

3.2 Species of itrogen fixing azospirilluum

  • Azospirillum brasilense.
  • Azospirillumcanadense.
  • Azospirillumdoebereinerae.
  • Azospirillumoryzae.
  • Azospirilluum agricola.

3.2.1Azospirillum brasilense

Presence: Rhizospheres of grasses.
Common in: Brazil.

3.2.2Azospirillum canadense 

Presence: Rhizospheres of maize.


Association: Roots of silvergrass.

Azoo halopraeferens

Presence: North America.
Association: Spangle top.


It is of commercial importance.

Association: Roots of paddy plants.
Presence: All over the world (rice growing regions of the world).

It was isolated from the roots of rice in Japan.

3.2.5 Azospirilluum agricola

Isolated form the agricultural land in Taiwan.

These are known for alternig atosphoric nitrogen into useable forms under the low oxygen condition.

Also read: Production of vermicompost

3.3 Role in plant growth

Mechanisms: They affect plant growth through various mechanisms such as the excretion of plant hormones.

Altering nitrogen and phosphorus: They alter phosphorus and nitrogen so they become available to plants.

Plant protection: They release antioxidants and compete with the different species of harmful microorganisms to indirectly favor the plant.

3.4 Method of application of azospyrillum in paddy fields

Seed treatment: Use 5 – 7 g of  azospyrillum for one kg or paddy seed.

Root treatment: Use 750 g of azospyrillum for one hectare of paddy field.

3.5 Commercially available azospirilluum product in market for rice/paddy plants

N Freelancer: Contains Azospirillum brasilense.
Rom- Azospirillum.
ABTEC Azospirillum.
Indian Agri Azospirillum Biofertilizer.

(4). PSB Culture (Phosphorus Solubilizing Bacteria)

4.1 About Phosphorus Solubilizing Bacteria (PSB)

Phosphorus is a non-solublized element in soil ecosystem. Hence, almost all plant receive merely 5 – 25 %  of applied phosphorus, and rest of the phosphorus remains in unsoluble form which is unavailable to plants.

The phosphorus solubilizing bacteria coverts the unsoluble amounts of phosphorus into soluble form present in soil. Now it is easily available to plants.

4.2 Species of phosphorus solubilizing bacterium

  • Pantoea agglomerans.
  • Microbacterium laevaniformans.
  • Pseudomonas putida.

4.2.1 Pantoea agglomerans

Note: It inhibits the growth of baby’s breath.

4.2.2 Pseudomonas putida

Habitat: Soil

4.2.3 PSB Strains

Sugarcane (strain from sugarcane): VIMP01 and VIMP02.
From sugar beet rhizosphere: VIMP03 and VIMP04.

4.2.4 Benefits:

Single super phosphate: By using phosphorus solubilizing bacteria, 60 kg of single super phosphate per hectare can be saved.

Increase in production: Research suggests that phosphorus solubilizing bacteria can increase rice production up to 3 to 7 percent.

4.3 Method of application of Phosprus Solubilizing Bacteria in paddy fields

Same as azospyrillum

Seed treatment: Use 5 – 7 g of PSB culture for one kg or paddy seed.

Root treatment: Use 750 g of PSB culture for one hectare of paddy field.

4.4 Some commercially available PSB (Phosphorus Soluble Bacteria) culture in market

  • PSB Con.
  • Phosphoz.
  • PSB by IFFCO.
  • NPK Mobilizing Biofertilizer.
  • Phoster.

(5). Care

  • Keep the culture packets in shade.
  • Always use recommend culture.
  • Sow the seeds immediately after treatment.
  • Don’t use expired products.
  • Combination of Phosphorus Solubilizing Bacteria and azospyrillum.

(6). Frequently Asked Questions

Questions 01. Can we use insecticides after the application of BGA?

Answer: Yes.

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