Himanshu Tiwari

Field-based studies conducted globally indicate that conservation agriculture—which includes minimal soil disturbance (no-till), permanent soil cover, and diversified crop rotations—can significantly contribute to the reduction of greenhouse gas (GHG) emissions, particularly CO₂ and N₂O. However, the effectiveness of these practices is highly dependent on local agroecological conditions, and site-specific evaluation is essential for successful implementation.

Conservation tillage reduces the oxidation of soil organic matter, potentially lowering CO₂ emissions, while crop residue retention enhances carbon sequestration. This effect is more pronounced in sandy or degraded soils, where erosion control is critical, whereas heavy clay soils may show limited benefits or even temporary increases in emissions due to poor aeration and moisture retention.

N₂O emissions present more variable results. In moist soils rich in organic matter—especially compacted soils—reduced tillage can increase denitrification, leading to higher N₂O emissions. In contrast, in dry and well-drained soils, no-till systems with legume-based rotations may reduce emissions through improved nitrogen use efficiency.

Soil type, climate, and crop rotation are critical factors:

• Well-drained, lighter soils generally respond more favorably to conservation practices in terms of GHG reduction.
• Heavy, poorly drained soils carry a higher risk of increased N₂O emissions.
• In drier, temperate climates, conservation agriculture often stabilizes emissions by improving moisture management.
• In warm and humid climates, rapid residue decomposition and high microbial activity may increase emissions unless carefully managed.
• Diverse and long-term crop rotations, especially those including legumes, promote better nitrogen and carbon balance, while monocultures may limit the effectiveness of conservation practices due to one-sided nutrient exploitation.

In conclusion, while conservation agriculture holds significant promise for reducing GHG emissions, its effectiveness is context-specific. Adaptive management that takes into account local soil characteristics, climate conditions, and cropping systems is essential. Further long-term field studies and emission monitoring under real farming conditions are crucial for developing region-specific guidelines and advancing climate-smart agriculture strategies

While the above answer details out the advantages, let me add that there has been undue emphasis on carbon while we still have not understood climate change properly. There was (now that both agri and natural forest cover have dwindled) earlier a great natural co-ordination between the two systems.