Previous Year Question

Water-use efficiency generally represents the crop output obtained per unit of water used. In this question, the options are compared in terms of their seasonal water requirement and ability to tolerate dry conditions.

Sugarcane is a long-duration and highly water-demanding crop. Its long growing period, large leaf area, high biomass production and continuous transpiration create a very high total water requirement.

FAO’s indicative estimates place the total growing-period water requirement of sugarcane at approximately 1,500–2,500 mm. In comparison, sunflower requires approximately 600–1,000 mm, while sorghum/millet requires about 450–650 mm.

Sunflower is a comparatively shorter-duration crop and requires considerably less water than sugarcane.

Pearl millet is drought tolerant. Its deep and extensive root system helps it utilise limited soil moisture, allowing cultivation in low-rainfall regions.

Red gram is also a deep-rooted pulse commonly grown under rainfed and semi-arid conditions. It can tolerate prolonged dry periods better than sugarcane.

Actual crop-water requirements vary with climate, variety, growing period, soil, effective rainfall and irrigation method. Drip irrigation, fertigation and trash mulching can improve sugarcane’s water-use efficiency; nevertheless, among the given options, sugarcane remains the most water-demanding and least water-efficient crop.