Consider the following agricultural practices: 1) Contour bunding 2) Relay cropping 3) Zero tillage In the context of global climate change, which of the above helps/help in carbon sequestration/storage in the soil?

All three practices help store carbon in soil, so the answer is C. Soil organic carbon builds up when more plant residue and root biomass return to the soil than are lost through decomposition and erosion. Practices that cut erosion, keep the soil covered and disturb it less all support this. Mains angle: climate-smart agriculture and soil health missions.

• Contour bunding: Bunds laid along contours slow runoff and trap eroding topsoil, which carries much of the organic carbon. Keeping that soil in place makes it a sequestration aid, not just a moisture conservation measure.
• Relay cropping: The second crop is sown before the first is harvested, so the land stays under vegetation for more of the year. Continuous root input and cover add organic matter.
• Zero tillage: Avoiding ploughing reduces the oxidation of organic matter and protects soil aggregates, so carbon stays in the soil rather than being released as CO2.

Option A drops zero tillage, which is the most widely cited sequestration practice. Options B and D are wrong because each practice contributes on its own.

Trap: Aspirants treat contour bunding as only a water-conservation measure and leave it out of the set. Its soil-carbon role through erosion control counts too.