Microbes as Biofertilisers — Core Principles

Core Principles

Biofertilisers are living microbial preparations that enhance soil fertility and promote plant growth by making essential nutrients more available to crops. They are a sustainable alternative to chemical fertilisers, reducing environmental pollution and improving soil health.

Key types include nitrogen-fixing microbes (e.g., *Rhizobium* for legumes, *Azotobacter* for non-legumes, cyanobacteria for paddy fields), phosphorus-solubilising bacteria (PSB) like *Bacillus* and *Pseudomonas*, and mycorrhizal fungi (e.

g., VAM fungi). These microbes work by converting atmospheric nitrogen into ammonia, solubilising insoluble phosphorus, or extending the root's absorptive surface area. Their application leads to increased crop yields, better nutrient uptake, and a healthier soil ecosystem, aligning with principles of organic and sustainable agriculture.

Important Differences

vs Chemical Fertilisers

Aspect	This Topic	Chemical Fertilisers
Nature	Living microorganisms (bacteria, fungi, cyanobacteria)	Synthetic, inorganic chemical compounds
Mechanism of Action	Enhance nutrient availability indirectly (N-fixation, P-solubilisation, growth promotion)	Directly supply nutrients in concentrated, readily available forms
Environmental Impact	Eco-friendly, improve soil health, reduce pollution (eutrophication, greenhouse gases)	Can cause soil degradation, water pollution, eutrophication, contribute to greenhouse gases
Nutrient Supply	Gradual, sustained release; improve nutrient use efficiency	Rapid, immediate nutrient supply; can lead to nutrient leaching
Cost	Generally cost-effective in the long run, lower input costs	Often expensive, increasing input costs for farmers
Soil Health	Improve soil structure, water retention, microbial diversity, and organic matter	Can negatively impact soil microbial life and structure with overuse
Specificity	Often crop-specific or soil-specific (e.g., *Rhizobium* for legumes)	Generally broad-spectrum, but specific formulations exist for different nutrient ratios

Biofertilisers are living microbial preparations that sustainably enhance soil fertility and plant nutrient uptake through natural biological processes, fostering long-term soil health and environmental protection. In contrast, chemical fertilisers are synthetic compounds that directly provide nutrients, offering rapid but often short-term benefits at the cost of environmental degradation and potential soil harm. While chemical fertilisers provide immediate nutrient boosts, biofertilisers promote a healthier, more resilient agricultural ecosystem, reducing reliance on external inputs and aligning with sustainable farming practices.