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World Soil Day: The Importance of Soil Health and Nutrient Circularity
Context:
World Soil Day (5, December 2024) emphasises the need to address India’s soil health crisis to ensure sustainable ecosystems, food security, and climate resilience. Nutrient circularity offers a promising solution by turning organic waste into a resource.
- This year’s theme, “Caring for Soils: Measure, Monitor, Manage,” highlights the critical role of accurate soil data and information in understanding soil properties and enabling informed decisions for sustainable soil management, which is essential for ensuring food security.
India’s Soil Health Crisis
- Widespread Nutrient Deficiencies: Around 90% of India’s topsoil is deficient in nitrogen and phosphorus, while 50% lacks potassium.
- Major Challenges: Soil erosion, degradation, and low nutrient and carbon content affect long-term agricultural sustainability.
Nutrient Circularity: A Multi-Solving Strategy
- Definition: The process of collecting, processing, and returning nutrients from urban organic waste to agricultural soil.
- Key Benefits: Replenishes soil nutrients, reduces waste, and supports circular economies at various scales.
Challenges with Waste-to-Energy (WtE) Technologies
- Dominance of Incineration Plants
- Prevalence: Incineration accounts for 81% of WtE technologies, such as Delhi’s reliance on it for waste management.
- High Costs and Failure Rates: Plants have high capital and operational expenses, with 50% failing over time.
- Environmental and Health Concerns: Emit significant greenhouse gases (1707 g CO2e/kWh) and toxic byproducts.
- Regulatory Issues: Lack of stringent standards and real-time monitoring.
- Biomethanation Plants
- Challenges: High failure rates due to poor waste segregation and maintenance.
- Methane Leakages: Risks of significant greenhouse gas emissions.
- Minimal Contribution: WtE plants generate only 0.1% of India’s renewable energy.
Reimagining Waste Management with Nutrient Circularity
- Organic Waste and Nutrient Flows: Urban waste represents lost nutrients that can be recovered and returned to rural soils.
- Composting: Converts organic waste into compost, rich in organic carbon (~20%), enhancing soil fertility and reducing reliance on chemical fertilisers.
- Cost Efficiency: Composting with fertilisers reduces production costs by 15–20% per hectare.
Policy Support and Shortcomings
- 2016 City Compost Policy: Introduced subsidies for compost but lacked quality assurance, testing standards, and public demand creation.
- Policy Withdrawal in 2021: Allocations for composting were reduced to zero, focusing solely on bio-methanation.
Successful Models of Nutrient Circularity
- City-Farmer Partnership (Chikkaballapur, Karnataka): Converted 759 tonnes of waste into compost for 109 farmers across 17 villages.
- Hub and Spoke Model (Alappuzha, Kerala): Facilitates compost transfer from urban hubs to rural areas.
Way Forward: Scaling Nutrient Circularity
- Top-Down Policy Push: National-level policies to promote compost quality, testing standards, and certifications.
- Bottom-Up Public Demand: Encourage farmer and community participation to increase compost adoption.
- Gradual Phase-Out of Chemical Fertilisers: Nutrient circularity can reduce dependence on chemical inputs over time.
