Question

The consumptive use of water for a crop during a particular stage of growth is 2.0 mm/day. The maximum depth of available water in the root zone is 60 mm. Irrigation is required when the amount of available water is 50% of the maximum available water in the root zone. Frequency of irrigation should be

• A. 10 days
• B. 15 days
• C. 20 days
• D. 25 days

Answer 1

The correct option is B 15 days

Consumptive use of water
= 2 mm/day
Maximum depth of water in the root zone
= 60 mm
Irrigation is required at 50% deficit
$\frac{50}{100}\times 60=30mm$

Frequency of irrigation
$=\frac{\text{Allowable deficit}}{\text{Consumptive use}}=\frac{30}{2}$

= 15 days