Previous Year Question

Oxygen becomes depleted in flooded paddy fields, creating anaerobic conditions. Microbial decomposition of organic matter under these conditions produces substantial methane (CH₄).

Nitrogen fertilizers used in rice fields and alternating wet and dry conditions influence nitrification and denitrification processes, which release nitrous oxide (N₂O).

Fertilized cotton, sugarcane and wheat fields may emit nitrous oxide, but they are not major methane sources comparable to flooded rice fields.

Therefore, among the given crops, rice is the most important anthropogenic source of both gases.