Correct Option (B)
Zero tillage is an agricultural practice where crops are planted without disturbing the soil through ploughing or tilling. This method significantly contributes to carbon sequestration in the soil by:
- Reducing the decomposition rate of soil organic matter, which prevents the release of stored carbon dioxide (CO₂) into the atmosphere.
- Promoting the accumulation of organic carbon in the soil over time, thereby enhancing soil carbon storage.
Incorrect Options
Contour bunding involves constructing small bunds (embankments) along the contours of a slope. Its primary purpose is to prevent soil erosion, conserve soil moisture, and control surface runoff. While it contributes to overall soil health and productivity, it does not directly or significantly lead to long-term carbon sequestration in the soil.
Relay cropping is a practice where a second crop is planted before the first crop is harvested, ensuring continuous land cover. This method aims to maximize land use efficiency and crop production. While it can increase biomass and potentially contribute to some organic matter input, its direct and significant role in long-term soil carbon sequestration is not considered a primary benefit in the context of global climate change mitigation through carbon storage.
Therefore, only zero tillage among the given practices directly helps in carbon sequestration/storage in the soil.