Among the following, which one is the least water-efficient crop?
Contents13
- ASugarcane
- BSunflower
- CPearl millet
- DRed gram
Show answer
Answer: (A) Sugarcane
Water efficiency refers to how much water is needed to produce a unit of crop.
Sugarcane requires about 1,500-2,000 litres of water per kg of sugar and needs continuous irrigation over 12-18 months.
Sunflower needs about 7-9 litres per kg.
Pearl millet (bajra) is a dryland crop grown with minimal irrigation.
Red gram (tur dal) is rain-fed, needing only 35-40 cm of water during its entire growth period, usually with no irrigation.
Among these, sugarcane is by far the least water-efficient.
Answer: (a).
Sugarcane consumes 1,500-2,000 litres of water per kg of sugar produced, making it India's most water-intensive crop despite covering only 4% of cultivated area.
Water stress and farmer distress in sugarcane belts like Maharashtra have made crop water efficiency a policy priority, with government push for less water-intensive alternatives.
The question tests understanding of water requirements across crop types - cash crops versus millets versus pulses - which is central to sustainable agriculture policy.
Sugarcane Cultivation & Water Requirements
Indian Economy Sugarcane
Sugarcane: India's Most Water-Intensive Crop
Sugarcane requires 1,500-2,000 litres of water per kg of sugar produced
Needs continuous irrigation over 12-18 months growing period
India is the 2nd largest sugarcane producer globally after Brazil
Major producing states: Uttar Pradesh, Maharashtra, Karnataka
Why Sugarcane is Water-Intensive
Sugarcane is a C4 photosynthesis crop with high biomass production, requiring massive water inputs throughout its extended growing cycle. Unlike seasonal crops, sugarcane remains in the field for over a year, demanding consistent moisture for optimal sugar accumulation.
Water Requirements & Irrigation
Requires 2,500-3,000 mm of water annually (rainfall + irrigation combined)
Needs irrigation every 7-10 days during peak growth period
Flood irrigation is commonly used, leading to water wastage
Drip irrigation can reduce water use by 30-40% but requires high investment
Water stress during grand growth phase (4-8 months) severely reduces yield
Sugarcane vs Other Crops - Water Efficiency
Crop | Water per kg Output | Growing Period | Irrigation Frequency |
|---|---|---|---|
Sugarcane | 1,500-2,000 L/kg sugar | 12-18 months | Every 7-10 days |
Sunflower | 7-9 L/kg | 3-4 months | 2-3 times |
Pearl Millet | 2-3 L/kg | 3-4 months | Rainfed/minimal |
Red Gram | 4-5 L/kg | 6-8 months | Rainfed |
Trap: Don't confuse water requirement per hectare with water efficiency per kg output
UPSC often tests relative water efficiency - sugarcane is always the least efficient among given options
Remember: Commercial crops (sugarcane, cotton) are generally more water-intensive than food grains
Sugarcane's long growing period makes it less water-efficient than crops with similar daily water needs
Dryland Crops & Water Efficiency
Indian Economy Sunflower Pearl millet Red gram
Dryland Crops: Water-Efficient Agriculture
Pearl millet and red gram are primarily rainfed crops requiring minimal irrigation
Sunflower needs only 7-9 litres water per kg of output
These crops have deep root systems and drought tolerance mechanisms
Suitable for semi-arid regions with 500-750mm annual rainfall
Water-Efficient Crop Characteristics
Crop | Water Requirement | Rainfall Dependence | Key Adaptation | Major Regions |
|---|---|---|---|---|
Pearl Millet (Bajra) | 2-3 L/kg | Rainfed | Drought tolerance | Rajasthan, Haryana, Gujarat |
Red Gram (Tur) | 35-40 cm total | Rainfed | Deep taproot | Maharashtra, Karnataka, MP |
Sunflower | 7-9 L/kg | Limited irrigation | Heliotropism | Karnataka, AP, Maharashtra |
Drought Adaptation Mechanisms
These crops survive water stress through various adaptations:
• Pearl millet: CAM-like photosynthesis, waxy leaves reduce transpiration
• Red gram: Deep taproot (up to 2 meters) accesses groundwater
• Sunflower: Heliotropism maximizes photosynthesis, reducing water stress duration
Cultivation Advantages
Require minimal external inputs - suitable for small and marginal farmers
Can grow in marginal lands with low soil fertility
Provide nutritional security in drought-prone areas
Climate resilient - important for climate change adaptation
Red gram improves soil fertility through nitrogen fixation
Dryland Farming Regions
Source: ScienceDirect.com — Identifying prospects and potential areas for introducing ... · www.sciencedirect.com
Don't assume all pulses are water-efficient - some like chickpea need more water than red gram
Sunflower is water-efficient per kg but still needs 2-3 irrigations unlike pure rainfed crops
UPSC may test regional specialization - pearl millet in Rajasthan, red gram in Deccan plateau
Remember: Coarse cereals (bajra, jowar) are generally more water-efficient than fine cereals (rice, wheat)
Crop Water Productivity & Efficiency
Indian Economy water-efficient
Understanding Crop Water Productivity in Indian Agriculture
Water productivity = kg of output per m³ of water consumed
C4 crops (sugarcane, maize) generally less water-efficient than C3 crops per unit output
Commercial crops typically require more water than food grains
Drip irrigation can improve water efficiency by 30-50%
Water Efficiency Metrics
Water efficiency is measured as output per unit of water consumed, not total water requirement. A crop needing less water overall isn't necessarily more efficient if its yield per unit water is lower.
Crop Categories by Water Efficiency
Efficiency Level | Crop Examples | Water Use (L/kg) | Typical Cultivation |
|---|---|---|---|
Most Efficient | Bajra, Jowar, Ragi | 2-4 L/kg | Rainfed dryland |
Moderately Efficient | Wheat, Sunflower, Pulses | 5-15 L/kg | Limited irrigation |
Less Efficient | Maize, Cotton, Soybean | 20-50 L/kg | Regular irrigation |
Least Efficient | Rice, Sugarcane | 100-2000 L/kg | Flood/continuous irrigation |
Factors Affecting Water Efficiency
# Crop Water Efficiency
## Plant Factors
- Photosynthesis type (C3/C4)
- Root depth
- Leaf characteristics
- Growth duration
## Environmental
- Temperature
- Humidity
- Wind speed
- Solar radiation
## Management
- Irrigation method
- Timing of water application
- Mulching
- Variety selection
## Economic
- Market value per kg
- Processing requirements
- Storage needs
- Transport costsDon't confuse total water requirement with water efficiency - rice needs lot of water but is still less efficient
Cash crops are often less water-efficient than subsistence crops per unit output
UPSC tests relative efficiency - among given options, identify the least/most efficient
Processing crops (sugarcane for sugar) show lower efficiency when calculated per unit of final product