Azotobacter (nitrogen-fixing biofertiliser)
The free-living nitrogen fixer for non-legumes — a low-cost boost to germination and early vigour in cereals and vegetables.
- What it is
- Free-living N-fixing bacteria
- Form
- Carrier-based / liquid inoculant
- Price
- Low (a few tens of ₹ per acre)
- Best for
- Cereals, vegetables, cotton
Overview
Azotobacter is a free-living (non-symbiotic) nitrogen-fixing bacterium — unlike Rhizobium it does not need to form nodules, so it works on non-legumes: wheat, rice, maize, cotton, vegetables and more. It fixes a modest amount of atmospheric nitrogen in the soil around the roots.
Its bigger day-to-day benefit is often the growth-promoting substances it produces (hormones and vitamins) that improve germination, root growth and early vigour, plus some suppression of root pathogens. It works best on soils already rich in organic matter, which feed the free-living bacteria — so it pairs naturally with FYM.
What it is and when to reach for it
- A free-living nitrogen fixer for non-legume crops — reach for it on cereals, vegetables and cotton, where Rhizobium does not apply.
- Value comes as much from its growth-promoting hormones and better germination as from the nitrogen it fixes.
- It supplements the nitrogen plan, trimming the urea dose modestly rather than replacing it.
How to use it well
- Seed treatment: coat seed with a slurry of the inoculant (with a sticker), dry in the shade and sow the same day.
- Soil / seedling: mix the recommended dose with FYM or compost and broadcast, or dip transplant roots in a suspension.
- It performs best on organic-rich, moist soil — combine it with FYM rather than expecting it to work on bare, depleted ground.
What it can and cannot do
- A living product — store cool and shaded, keep away from fungicides and agrochemicals, and use before expiry.
- It fixes less nitrogen than a well-nodulated legume with Rhizobium, so treat the nitrogen saving as modest.
- Its benefit is smaller on soils very low in organic matter, because the free-living bacteria have little to live on.
Common mistakes
- Expecting it to replace most of the urea — the free-living fixation is modest, not a full nitrogen source.
- Mixing it with fungicide-treated seed or spraying it with an agrochemical, which kills the bacteria.
- Using it on bare, organic-poor soil and in the midday sun, where survival is poor.
Crops it is used on
Open a crop for its full nutrient schedule.
Common questions
What is the difference between Azotobacter and Rhizobium?
Rhizobium is symbiotic — it forms nodules on legume roots and works only on pulses and legumes. Azotobacter is free-living, fixing nitrogen in the soil without nodules, so it is used on non-legumes like wheat, rice, maize and vegetables. Cereals and vegetables get Azotobacter (or Azospirillum), never Rhizobium.
How much nitrogen does Azotobacter save?
A modest amount — as a free-living fixer it adds less nitrogen than a well-nodulated legume with Rhizobium. Treat it as a supplement that trims the urea dose and improves germination and vigour, not as a replacement for the crop’s nitrogen fertiliser.
How is Azotobacter applied?
As a seed treatment (coat the seed with a slurry, dry in shade, sow the same day), mixed into FYM/compost and broadcast, or as a root dip for transplants. Keep it away from fungicides and agrochemicals, and store it cool and shaded until use.
Composition and doses follow ICAR / Soil Health Card guidance; prices are the notified subsidised rates for the season shown and are guidance, not a quote. A soil test for your field always beats a general rate. See our editorial policy.