What are nano-fertilisers or biostimulants?

Why in News? Union Agriculture Minister Shivraj Singh Chouhan recently wrote to the Chief Ministers of all states urging them to immediately stop the “forced tagging” of nano-fertilisers or biostimulants along with conventional fertilisers like urea and diammonium phosphate (DAP).

This action came in response to widespread complaints from farmers, who reported that retailers were not providing subsidised fertilisers unless they also bought biostimulants — an unethical practice that increases farmers’ financial burden and violates policy norms.

What are Biostimulants?

Definition:
Biostimulants are substances or microorganisms applied to plants or soils with the purpose of enhancing plant growth, yield, quality, and tolerance to stress, without acting as direct sources of nutrients.

Key Features of Biostimulants:

1. Not Fertilisers:
   They do not contain significant amounts of nutrients like nitrogen, phosphorus, or potassium, which are present in chemical fertilisers. Instead, they improve the plant’s ability to utilize available nutrients more efficiently.

2. Stress Tolerance:
   Help plants withstand abiotic stresses such as drought, heat, salinity, and cold.

3. Improved Soil Health:
   Stimulate beneficial microbial activity in soil, enhancing soil fertility and structure.

4. Growth and Yield Enhancers:
   Promote better root development, flowering, fruiting, and overall crop productivity.

Types of Biostimulants:

• Humic and Fulvic Acids: Improve nutrient uptake and stimulate root development.

• Seaweed Extracts: Rich in natural plant hormones; promote growth.

• Protein Hydrolysates and Amino Acids: Support enzyme activity and metabolism.

• Beneficial Microbes: Such as mycorrhizal fungi and rhizobacteria; help in nitrogen fixation and phosphorus solubilization.

• Chitosan and other Biopolymers: Induce plant defense mechanisms.

• Silicon-based Compounds: Enhance resistance against physical and biological stress.

Benefits of Biostimulants:

• Enhance agricultural sustainability

• Reduce dependency on chemical fertilisers

• Support organic and natural farming

• Improve crop quality and nutrient density

• Environmentally friendly and safe for long-term use

Concerns Raised:

• Forced Bundling: Retailers allegedly forcing farmers to purchase biostimulants along with subsidised fertilisers, which violates farmers’ choice and increases costs.

• Regulatory Gaps: Biostimulants are relatively new, and regulatory frameworks are still evolving in India.

• Efficacy Claims: Not all biostimulants in the market have proven efficacy; some may be of questionable quality.