Among the following crops, which one is the most important anthropogenic source of both methane and nitrous oxide ?
Show answer
Answer: B. Flooded rice paddies have no oxygen in the soil, so microbes release methane. Heavy nitrogen fertiliser use and alternate wet and dry phases in paddies also release nitrous oxide. So rice is the most important crop source of both gases.
Watch for: Students link nitrous oxide to fertiliser-heavy crops like wheat and forget that only flooded rice produces large methane emissions.
Why the other options are wrong
- A. Wrong because cotton is grown on dry fields and is not a major methane source.
- C. Wrong because sugarcane is not flooded like paddy and is not a major methane source.
- D. Wrong because wheat is grown on unflooded fields and emits little methane.
Source to check: IPCC AR6 WG3, Chapter 7 (Agriculture); India's Biennial Update Report to UNFCCC (agriculture emissions)
Answer from the official UPSC key. Written and fact-checked by AI against the official key. Spotted a mistake? Report it.