PSB for Rice–Mustard Cropping Systems in Assam | Phosphate Solubilizing Bacteria Supplier India

The rice–mustard cropping system is an important agricultural sequence in Assam, where rice grown during the monsoon season may be followed by mustard during the rabi season. Maintaining adequate phosphorus availability across successive crops is important for root development, crop establishment and overall nutrient management.

However, not all phosphorus present in agricultural soil is immediately available to plants. Depending on soil pH, mineral composition and other conditions, phosphorus can become associated with compounds that reduce its plant availability.

Phosphate Solubilizing Bacteria (PSB) are beneficial microorganisms used as microbial biofertilizers to support the conversion of certain poorly soluble forms of phosphorus into more plant-accessible forms.

Why PSB Is Relevant to Assam

Many agricultural soils in Assam are acidic. Under acidic conditions, phosphorus availability can be constrained through interactions with soil minerals, particularly iron- and aluminium-associated compounds.

PSB can contribute to biological phosphorus cycling by producing organic acids and other metabolites that help solubilize certain mineral phosphate forms.

PSB should not be viewed as a universal substitute for phosphorus fertilizer. Instead, it can be incorporated into an Integrated Nutrient Management (INM) program based on soil testing, crop requirements, fertilizer inputs, organic matter and soil pH.

PSB for Rice Cultivation

Rice requires phosphorus during important stages of establishment and development. A suitable phosphorus environment is particularly important for early root growth and crop establishment.

PSB can be introduced into the rice rhizosphere through appropriate seed, nursery, seedling, soil or root-zone applications depending on the formulation.

Maintaining beneficial microbial populations around rice roots may support biological phosphorus cycling throughout crop development.

PSB for Mustard Cultivation

Mustard also requires adequate phosphorus for root development, establishment and reproductive growth.

When mustard follows rice, nutrient management should consider both the residual nutrient status after the rice crop and the requirements of the following mustard crop.

Applying PSB as part of the mustard nutrient program can help maintain biological activity associated with phosphorus cycling in the rhizosphere.

PSB in Rice–Mustard Rotation

A rice–mustard rotation places repeated nutrient demand on agricultural soil. Managing the cropping sequence as a system rather than treating each crop independently can improve long-term fertility planning.

PSB can be incorporated into both crops where agronomically appropriate.

For rice, it may be introduced during nursery, transplanting or soil-management stages. For mustard, it may be introduced through seed treatment, soil application or root-zone programs.

The objective is to maintain a biologically active soil environment rather than expecting one microbial application to remain effective indefinitely across both crops.

PSB and Organic Matter

Organic matter is important for maintaining soil biological activity.

PSB formulations may be incorporated with well-decomposed FYM or compost where the product instructions allow. Organic amendments can provide carbon sources and suitable microenvironments for beneficial soil microorganisms.

Using PSB alongside good organic-matter management can therefore form part of a broader soil-fertility strategy.

PSB with Other Biofertilizers

PSB can be integrated with other beneficial microorganisms according to crop requirements.

For rice and mustard, a microbial program may include:

Azotobacter for biological nitrogen-management programs.

Azospirillum particularly within cereal-oriented microbial programs.

KMB for biological potassium mobilization.

ZSB for biological zinc-solubilization programs.

Sulphur Solubilizing Bacteria (SSB) where sulphur management is important, particularly for mustard.

NPK microbial consortium for combined microbial nutrient-management programs.

The microorganisms selected should correspond to soil-test results and actual crop requirements.