Step 1: Understanding the Question:
The question requires arranging different irrigation methods based on their Water Use Efficiency (WUE), from the most efficient to the least efficient.
Water Use Efficiency is defined as the ratio of water utilized by the crop to the total water applied.
Detailed Explanation:
• Pitcher Pot Irrigation (Highest):
This is an ancient localized irrigation method where unglazed porous clay pots are buried in the soil near the plant roots.
Water seeps out slowly due to the matric suction of the dry soil.
It can achieve efficiencies exceeding $90-95\%$ because evaporation losses are nearly zero and water is delivered exactly at the root zone.
• Drip Irrigation:
A modern micro-irrigation system that delivers water drop by drop near the plant base.
Efficiency is very high ($85-95\%$) as it minimizes runoff and deep percolation.
In many comparative studies, Pitcher pot and Drip are close, but Pitcher pot is often cited as slightly more efficient in small-scale desert farming due to zero pressurized losses.
• Sprinkler Irrigation:
Water is sprayed into the air and allowed to fall like rain.
Efficiency is moderate to high ($70-85\%$).
It loses more water than drip due to wind drift and evaporation while the droplets are in the air.
• Surface Irrigation (Lowest):
Includes flooding, furrow, or basin irrigation.
Efficiency is low ($40-60\%$) because a large amount of water is lost to surface runoff and deep drainage beyond the root zone.
Step 2: Final Answer:
The order of decreasing efficiency is Pitcher pot $>$ Drip $>$ Sprinkler $>$ Surface.