In the context of India, which of the following is/are considered to be practice(s) of eco-friendly agriculture? 1) Crop diversification 2) Legume intensification 3) Tensiometer use 4) Vertical farming Select the correct answer using the code given below:

The correct answer is D. All four practices are recognised as eco-friendly agriculture, and the question tests whether you can see the common thread: lower chemical input, better water use, and healthier soil.

• 1) Crop diversification: Growing a mix of crops or rotating them breaks pest and disease cycles, reduces dependence on synthetic pesticides, and spreads soil nutrient demand. This is the core of sustainable farming.
• 2) Legume intensification: Pulses host Rhizobium bacteria that fix atmospheric nitrogen, so they reduce the need for urea and improve soil fertility for the next crop. Pulse-based cropping systems are promoted under the national pulses missions.
• 3) Tensiometer use: It measures soil moisture tension, so the farmer irrigates only when the crop actually needs water. This prevents over-irrigation, waterlogging and salinity, and supports water conservation.
• 4) Vertical farming: Stacking crops in controlled environments, often hydroponic or aeroponic, uses far less land and water per unit of produce. Its energy use is high, which is a caveat for the Mains answer on its overall sustainability.

The concept links to climate-resilient and sustainable agriculture, which features in the GS-III food security and environment syllabus. A Mains answer on sustainable agriculture should name these practices along with their input-saving logic.

Trap: Aspirants often reject vertical farming as not really agriculture or too technological to count as eco-friendly, or they treat the tensiometer as a mere gadget rather than an irrigation practice.