Consider the following agricultural practices:

Answer: (c) 1, 2 and 3

All three practices help keep carbon in the soil. Zero tillage avoids the oxidation of soil carbon that ploughing causes. Relay cropping keeps living cover and roots in the field for longer, which adds biomass. Contour bunds hold back runoff and soil, so the carbon in the topsoil is not washed away.

• ✓ 1. Contour bunds slow runoff and cut soil loss on slopes. Erosion directly reduces soil carbon stocks, so checking erosion keeps carbon stored in the soil.
• ✓ 2. Relay cropping is a form of intercropping in which the next crop is sown before the earlier one is harvested. This keeps the land under crop cover for longer. It adds biomass above and below ground, which improves carbon sequestration.
• ✓ 3. Zero tillage leaves the soil undisturbed, so less organic matter is oxidised and lost as CO2. Soil carbon has been found to rise by 10–30 percent when conventional tillage is replaced by no-till.
• ✗ (b) This option credits only zero tillage. Contour bunding (by preventing carbon loss through erosion) and relay cropping (by adding biomass) also help store carbon in the soil.
• ✗ (d) This option says that none of the practices helps. That is wrong, because each of the three conserves or adds soil carbon.

Remember · Soil carbon is built by minimum disturbance (zero tillage), more biomass and continuous cover (relay or intercropping), and erosion control (bunds, contour farming).

Question: UPSC Civil Services (Preliminary) 2012, General Studies paper. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). · Report an error