06 · GS-III: Environment, Soil Biology & Bio-Fertilizers
Soil Microbiome Depletion: Chemical Fertilizer Imbalances, Mycorrhizal Inoculants and Natural Farming Protocols
NEWS PEG
- Agricultural research studies by ICAR and Indian Institute of Soil Science (IISS) warned that chronic over-application of synthetic chemical fertilizers and pesticides has depleted beneficial soil microbiome diversity by over 40% across intensively farmed regions.
- The assessment revealed severe degradation in soil biological enzyme activity and organic carbon (SOC dropped below 0.3% against the recommended >0.8%), impairing natural nutrient cycling and plant immune defenses.
- The Ministry of Agriculture launched a dedicated mission to scale biological bio-fertilizers—including Arbuscular Mycorrhizal Fungi (AMF), Phosphate Solubilizing Bacteria (PSB), and Azotobacter—under the National Mission on Natural Farming.
STATIC FOUNDATION
- Soil Organic Carbon (SOC): Primary indicator of soil health; critical for soil water retention, microbial diversity, cation exchange capacity, and aggregate stability.
- Arbuscular Mycorrhizal Fungi (AMF): Symbiotic soil fungi that penetrate plant root cortical cells, extending extensive hyphal networks to mobilize insoluble phosphorus, zinc, and micronutrients in exchange for plant carbohydrates.
- Bio-Fertilizers Classification:
- Nitrogen-Fixing: Rhizobium (symbiotic with legumes), Azotobacter (free-living aerobic in non-legumes), Azospirillum (associative in cereals), Blue-Green Algae (BGA) / Azolla (in paddy).
- Phosphorus-Solubilizing: Bacillus megaterium, Pseudomonas putida, Aspergillus.
- National Mission on Natural Farming (NMNF): Aims to promote chemical-free natural farming (Bhartiya Prakritik Krishi Paddhati) across 1 crore farmers.
PRELIMS TRAP & PYQ BRIDGE
MAINS ENHANCEMENT
- Restoring Soil Biology: From Chemical Injections to Living Soil Ecosystems — Transitioning from synthetic fertilizers to bio-fertilizers and compost cover cropping.
- Enhancing Climate Resilience: Mycorrhizal Fungi & Drought Resistance — How fungal hyphae networks improve plant water uptake during prolonged dry spells.
- Quality Control in Bio-Inputs: Fertilizer Control Order (FCO) Standards — Ensuring commercial bio-fertilizers maintain high viable microbial colony counts without contamination.