Context: A recent ICAR study has found that climate change and unbalanced fertiliser use are accelerating the decline of Soil Organic Carbon (SOC) in India’s farmlands.
SOC is vital for soil fertility, water retention, and carbon sequestration — making it central to both food security and climate resilience.
Key Findings of the ICAR Study
- SOC levels increase with elevation and decline with temperature, explaining higher carbon retention in hilly regions compared to plains.
- Haryana, Punjab, and western Uttar Pradesh show the highest decline due to overuse of urea and phosphorus-based fertilisers.
- Low SOC is directly linked to micronutrient deficiency and declining crop yields.
Understanding Soil Organic Carbon
- SOC is the carbon component of soil organic matter, accounting for 50–60% of its weight.
- Healthy soils contain 1–6% SOC, derived from decomposed plants, roots, and microbes.
- SOC is the key determinant of soil fertility, microbial activity, and moisture retention.
Determinants of SOC
- Temperature: Cooler regions retain more carbon; warmer climates accelerate decomposition.
- Rainfall: Moderate rainfall aids vegetation growth; arid zones lose carbon through erosion.
- Soil Texture: Clay soils preserve carbon better than sandy soils.
- Vegetation Type: Grasslands and forests differ in carbon storage patterns.
- Topography: Slopes lose SOC due to erosion, while valleys accumulate it.
Benefits of High SOC
- Improves soil structure and resistance to erosion.
- Enhances nutrient availability and microbial balance.
- Increases water retention and irrigation efficiency.
- Acts as a carbon sink, mitigating climate change.
- Reduces dependence on chemical fertilisers.
Factors Reducing SOC
- Intensive tillage and residue burning.
- Overuse of chemical fertilisers.
- Deforestation and land-use change.
- Warming temperatures and soil erosion.
Way Forward
- Promote organic manures, composting, and biochar.
- Encourage no-till and cover cropping practices.
- Introduce carbon farming incentives and carbon credit markets.
- Develop soil carbon monitoring systems under ICAR–NBSS&LUP.
- Integrate SOC management into National Mission for Sustainable Agriculture (NMSA).
Conclusion
Soil Organic Carbon is the lifeline of Indian agriculture.
Its conservation is not just an agronomic necessity but a climate imperative — essential for restoring soil vitality, ensuring food security, and achieving India’s carbon neutrality goals.