Among the following crops, which one is the most important anthropogenic source of both methane and nitrous oxide ?
- A.Cotton
- B.Rice
- C.Sugarcane
- D.Wheat
Correct answer
Explanation
The correct answer is B, Rice. Flooded paddy fields release methane, and the nitrogen fertiliser used on them releases nitrous oxide, so rice is the main crop source of both gases.
When a paddy field stands under water, the soil runs out of oxygen and methanogenic bacteria break down organic matter into methane, which escapes mostly through the rice plants. Rice paddies give roughly a tenth of man-made methane. Urea and other nitrogen fertilisers are partly converted by soil microbes into nitrous oxide, especially when fields are wetted and dried. Both are strong greenhouse gases, much more powerful than carbon dioxide.
A is wrong: cotton is grown on dry, aerated fields that produce no significant methane.
C is wrong: sugarcane uses fertiliser but is not grown under standing water, so its methane output is small.
D is wrong: wheat is a dry-land crop and is not a major methane source.
Alternate wetting and drying and direct seeding of rice are promoted to cut these emissions.
Exam tip: paddy = methane (waterlogging) + nitrous oxide (nitrogen fertiliser).
Practice Questions
View allEnergy-intensive industries and establishments notified under the Energy Conservation Act, 2001 are known as
- A.Designated consumers
- B.Obligated entities
- C.Accredited auditors
- D.State designated agencies
Show answer
The Act lists energy-intensive sectors in a schedule, and units in them above a notified threshold of annual energy consumption become designated consumers; each must appoint or designate an energy manager, have an energy audit carried out at prescribed intervals, keep records of energy consumed and comply with the consumption…
Read the full explanation →Which of the following was introduced by the Energy Conservation (Amendment) Act, 2022?
- A.Carbon Credit Trading Scheme
- B.Renewable Purchase Obligation
- C.Coal cess for the National Clean Energy Fund
- D.National Solar Mission
Show answer
The 2022 amendment to the Energy Conservation Act empowered the Central Government to specify a carbon credit trading scheme, to prescribe a minimum share of non-fossil energy for designated consumers, and to extend the building code to large residential buildings.
Read the full explanation →The Energy Conservation Building Code, as launched in 2007, applied to new commercial buildings having a connected load of at least
- A.10 kW
- B.50 kW
- C.100 kW
- D.500 kW
Show answer
The code was drawn up by the Bureau of Energy Efficiency for new commercial buildings with a connected load of 100 kW or more, or a contract demand of 120 kVA or more, and it prescribes requirements for the building envelope, lighting, air conditioning, water heating and electrical systems.
Read the full explanation →Under the Perform, Achieve and Trade scheme, a unit that exceeds its energy saving target is issued
- A.Renewable Energy Certificates
- B.Energy Saving Certificates
- C.Carbon Emission Reduction units
- D.Green Bonds
Show answer
PAT gives each designated consumer a target to reduce its specific energy consumption over a cycle; a plant that overshoots the target earns ESCerts and may sell them on the power exchanges to a plant that has fallen short, which turns efficiency into a tradable commodity.
Read the full explanation →National Energy Conservation Day is observed in India on
- A.5 June
- B.14 December
- C.28 February
- D.22 April
Show answer
The Ministry of Power observes National Energy Conservation Day on this date every year, and the national energy conservation awards are given to industries, buildings and institutions that have cut their energy use.
Read the full explanation →