Can Biofertilisers Reduce Chemical Fertiliser Use? What Farmers Need to Know Before Applying Them

Biofertilisers contain beneficial microorganisms that can help plants access nutrients from soil or fix atmospheric nitrogen. ICAR has promoted microbial products such as Bio-NPK and phosphate-solubilising formulations as part of integrated nutrient management, where biological inputs are used alongside soil testing and other nutrient sources.

These products can reduce dependence on chemical fertilisers in some farming systems, but farmers should not treat them as a complete replacement for fertilisers. Their performance depends on the microorganism, crop, soil condition, application method and quality of the product being used.

What are biofertilisers?

Biofertilisers are agricultural inputs containing living microorganisms that perform specific functions related to plant nutrition. These organisms can fix nitrogen, make phosphorus more available or help mobilise nutrients such as potassium and zinc around plant roots.

ICAR lists several groups, including Rhizobium, Azotobacter, Azospirillum, phosphate-solubilising bacteria and mycorrhiza. Different microorganisms work with different crops, so farmers should select products according to the crop and recommended application method.

Rhizobium bacteria form associations with the roots of legumes such as pulses. They help fix atmospheric nitrogen, making nitrogen available within the plant-soil system when the right bacterial strain and crop combination are present.

Farmers should not assume that any Rhizobium product works equally well on every pulse. ICAR notes that different Rhizobium strains are used for different legumes, making crop-specific selection important before seed treatment.

Azotobacter is a free-living nitrogen-fixing bacterium that can be used with several crops. The Principal Scientific Adviser office lists an ICAR-NBAIM-supported liquid Azotobacter formulation that can supplement nitrogen and also produce plant-growth-promoting compounds.

The product is designed as a seed inoculant and has a one-year shelf life. Such information shows why farmers should check the formulation’s label, recommended crop and storage conditions before purchasing it.

What are phosphate-solubilising bacteria?

Some soil phosphorus exists in forms that plants cannot readily use. Phosphate-solubilising microorganisms can help convert part of this phosphorus into forms that are more available to plants.

ICAR-NBAIM recently demonstrated Bio-Phos to farmers in Uttar Pradesh. Scientists explained that the microbial formulation helps convert insoluble phosphorus into plant-available forms, supporting phosphorus uptake and crop growth.

Some microbial formulations combine microorganisms with different functions. ICAR’s KASHI AZOBC, for example, combines nitrogen fixation, phosphate solubilisation and potassium mobilisation in one formulation.

ICAR-IIVR offers the formulation in liquid, powder and granular forms. The liquid version has separate recommended rates for seed treatment, root or seedling dipping and soil application, showing that application depends on how the product is used.

Farmers should not assume that biofertilisers can completely replace urea. Their contribution to nitrogen supply varies with the microorganism, crop, soil and growing conditions.

Some products can supplement nitrogen availability, but crops may still require additional nitrogen based on soil fertility and expected yield. Soil testing and crop-specific recommendations should guide the final fertiliser plan rather than reducing fertiliser automatically.

Can they replace phosphorus fertiliser?

The same principle applies to phosphorus. Phosphate-solubilising bacteria can improve the availability of phosphorus already present in the soil, but they do not create unlimited phosphorus for the crop.

Farmers should use soil-test results to understand phosphorus status. A biofertiliser may help improve nutrient availability, but it should be part of a broader nutrient-management plan rather than a substitute for every phosphorus application.

Application depends on the formulation. Common methods include seed treatment, seedling root dipping and direct soil application. ICAR’s recent farmer programme in Goa covered all three methods while explaining different microbial groups and their specific functions.

Farmers should follow the product label rather than using one method for every biofertiliser. The required dose, dilution, crop and application timing can vary significantly between formulations and microorganisms.

Seed treatment places beneficial microorganisms close to the emerging roots. This can help establish the microbial association early in crop growth, provided the product is suitable for the crop and remains viable.

Farmers should avoid mixing biofertiliser with chemicals unless the product instructions specifically permit it. They should also prepare treated seed according to the recommended procedure and sow it within the suggested period.

Microbial products contain living organisms, so storage conditions matter. Excessive heat, direct sunlight and unsuitable storage can reduce the viability of microorganisms before the product reaches the field.

Farmers should check the manufacturing date, expiry date, storage instructions and recommended temperature before buying. ICAR has developed liquid formulations with longer shelf life, but individual products still need to be stored according to their instructions.

Does the expiry date matter?

Yes. A biofertiliser that has passed its recommended shelf life may contain fewer viable microorganisms and may not perform as expected.

ICAR technologies show that shelf life varies between products. Its NutMagic groundnut biofertiliser, for example, has a stated shelf life of 12 months at 25–35°C. Farmers should therefore check the specific product rather than assuming all biofertilisers have the same storage period.

Some microbial inputs can be multiplied or produced through specific technical processes, but farmers should not assume that homemade cultures have the same quality or microbial count as tested formulations.

ICAR’s farmer programmes include training on microbial technologies and application methods. For commercial or large-scale use, farmers should rely on verified products that meet applicable quality standards and carry clear instructions.

Does soil testing still matter?

Yes. Biofertilisers work within the existing soil nutrient system, so farmers need to know which nutrients are deficient or already available.

ICAR-NBAIM has repeatedly linked microbial biofertiliser use with integrated nutrient management and periodic soil testing. The aim is to improve nutrient availability and use efficiency rather than replace soil testing with a biological product.

They may reduce input costs when they improve nutrient use and allow farmers to use fertilisers more precisely. The actual saving depends on the product, crop response, fertiliser prices, application costs and local conditions.

ICAR reports that its NutMagic formulation for groundnut can save part of nitrogenous, phosphatic and potassic fertiliser use, along with input-cost savings under validated conditions. Such figures should not be assumed for every crop or product.

Farmers should avoid buying products without checking the crop recommendation, microbial content, expiry date and storage requirements. They should also avoid using an incorrect dose or assuming that a product meant for one crop will work equally well elsewhere.

Another mistake is stopping chemical fertilisers without checking nutrient requirements. Biofertilisers work best when farmers use them as part of an integrated nutrient plan based on soil conditions and crop needs.

What should farmers check before buying?

Check the microorganism, target crop, formulation, dose, application method, manufacturing date, expiry date and storage conditions. Farmers should also verify whether the product comes from a recognised source and meets the required specifications.

Ask whether the product has been tested for the crop you grow. A product with a long list of claimed benefits is not automatically suitable for every soil, crop or farming system.

Biofertilisers can help farmers improve nutrient availability and reduce dependence on chemical fertilisers, but their role depends on the crop, soil and microorganism involved. ICAR’s current work includes Bio-NPK, Bio-Phos and other microbial technologies designed for specific nutrient functions.

The practical approach is to use biofertilisers as one part of integrated nutrient management. Test the soil, select a crop-specific product, follow the recommended application method and continue supplying nutrients that the crop still needs.