What is water-use efficiency? Describe the role of micro-irrigation in increasing the water-use efficiency.

Water-use efficiency (WUE) is the agricultural output — crop yield or biomass — obtained per unit of water consumed. Higher WUE means 'more crop per drop'. It is critical for India, which supports about 18 percent of the world's population with only around 4 percent of its water resources, and where agriculture consumes the bulk of freshwater.

Micro-irrigation and its role

Micro-irrigation delivers water in a controlled, low-volume manner directly to the plant root zone through drip and sprinkler systems, unlike wasteful flood irrigation.

• Targeted root-zone delivery sharply cuts conveyance, runoff and deep-percolation losses, raising WUE.
• Reduced surface wetting lowers evaporation and suppresses weed growth.
• Fertigation — applying fertiliser through the drip line — improves nutrient-use efficiency alongside water.
• It saves 30-50 percent water while raising yields, and enables cultivation on undulating or water-scarce land.
• Lower water and power use for pumping conserves groundwater and energy.

Conclusion

Micro-irrigation is central to sustainable agriculture. Schemes such as Pradhan Mantri Krishi Sinchayee Yojana with its 'Per Drop More Crop' component promote it to secure both water and food.