IAS Prelims Geography GQ-4 – 2021 | Agriculture: Water Use Efficiency
Authentic Classroom Explanation by IAS Monk
📍 The Question
Among the following, which one is the least water-efficient crop?
(a) Sugarcane
(b) Sunflower
(c) Pearl millet
(d) Red gram
✅ Correct Answer: (a) Sugarcane
🎯 Theme of the Question
Indian Geography | Agriculture | Cropping Patterns | Water Footprint
This is a resource-efficiency question, testing awareness of water consumption in crops, a recurring UPSC focus in the context of water stress and sustainability.
🧠 Classroom Explanation
Let us compare the water requirements of each crop.
🔹 Sugarcane ❌ (Least water-efficient)
- Requires very large quantities of water
- Approximate water footprint:
- ~200–250 litres of water per kg of sugarcane
- Long-duration crop (10–18 months)
- Heavy irrigation requirement, especially in tropical regions
✔️ Sugarcane is one of the most water-intensive crops in India.
🔹 Sunflower ✅ (More water-efficient)
- Requires moderate irrigation
- Approximate water use:
- 7–9 litres per kg
- Often grown under semi-arid conditions
🔹 Pearl millet (Bajra) ✅
- A drought-resistant millet
- Thrives in dry and semi-arid regions
- Minimal irrigation requirement
- High water-use efficiency
🔹 Red gram (Pigeon pea) ✅
- Mostly a rain-fed pulse crop
- Requires about 35–40 cm rainfall during its entire growth period
- Irrigation needed only at critical stages (flowering, pod formation)
📊 Final Assessment
| Crop | Water Requirement |
|---|---|
| Sugarcane | Very high (least efficient) ❌ |
| Sunflower | Moderate |
| Pearl millet | Very low |
| Red gram | Low |
👉 Correct answer: (a) Sugarcane
🧩 Memory Hook
“Sweet crop, thirsty roots — sugarcane drinks the most.”
🧠 Prelims Strategy Insight
UPSC often:
- Links cropping choices with sustainability
- Tests awareness of hidden water footprints
- Sugarcane & paddy = default high-water traps
🧭 IAS Monk Whisper
Not every green field is sustainable —
some drink tomorrow’s water today.