Bio-stimulants
Bio stimulants are substances or microorganisms added to fertiliser or soil that enhance plant growth and stress tolerance not by directly supplying nutrient elements, but by stimulating physiological processes.
They differ from traditional fertilisers (N-P-K) and from pesticides. Their action is mostly regulatory or metabolic.
They can be formulated alone or blended with conventional fertilisers.
Core Categories of Biostimulants
1. Humic and Fulvic Acids
o Derived from organic matter decomposition.
o Improve soil structure and nutrient chelation.
o Enhance root growth, cation exchange capacity (CEC), and nutrient uptake.
2. Seaweed & Plant Extracts
o Contain phytohormones (auxins, cytokinins), betaines, oligosaccharides.
o Promote cell division, stress signalling, drought resistance.
3. Microbial Inoculants
o Beneficial fungi/bacteria like Trichoderma spp., Bacillus spp., Rhizobium, Azospirillum.
o Functions:
▪ Biological N-fixation
▪ Phosphate solubilization
▪ Enzyme release in the rhizosphere
4. Amino Acids & Peptides
o Derived from protein hydrolysates.
o Improve nitrogen metabolism, antioxidative responses, and stress mitigation.
5. Organic Acids & Vitamins
o Examples: citric acid, malic acid, thiamine.
o Act as metabolic enhancers and co-factors in enzymatic pathways.
