GATE 2022 CE (CE1) – Question 34
During a particular stage of the growth of a crop, the consumptive use of water is 2.8 mm/day. The amount of water available in the soil is 50 % of the maximum depth of available water in the root zone. Consider the maximum root zone depth of the crop as 80 mm and the irrigation efficiency as 70 %. The interval between irrigation (in days) will be _________. (round off to the nearest integer)
Practise this question in The GATE Grind →
Show answer and explanation
Correct answer: 14
Explanation
The stated water **already available in the soil** is $0.5(80)=40$ mm. At a consumptive use of 2.8 mm/day, that storage lasts $40/2.8=14.2857$ days, rounded to **14 days**.
Irrigation efficiency determines the gross water needed to replenish the storage, not the rate at which stored soil water is consumed.