Question

In an irrigated plot the net irrigation requirement of crop is found to be 14.9 cm, the application efficiency is 80% and water conveyance efficiency is 70%. What is the gross irrigation requirement (GIR)?

• A. 18.6 cm
• B. 20.5 cm
• C. 23.8 cm
• D. 26.6 cm

Hint:

Always convert efficiency percentages to decimals before using in calculations. Multiply application and conveyance efficiencies to get overall efficiency.

Answer 1

The Correct Option is D

Gross Irrigation Requirement (GIR) is calculated using the formula: \[ \text{GIR} = \frac{\text{Net Irrigation Requirement}}{\text{Water Application Efficiency} \times \text{Water Conveyance Efficiency}} \]
Given:
Net Irrigation Requirement = 14.9 cm
Application Efficiency = 80% = 0.80
Water Conveyance Efficiency = 70% = 0.70
Step 1: Calculate combined efficiency
\[ \text{Overall Efficiency} = 0.80 \times 0.70 = 0.56 \]
Step 2: Calculate GIR
\[ \text{GIR} = \frac{14.9}{0.56} \approx 26.6 \text{ cm} \]
Therefore, the gross irrigation requirement is \( \boxed{26.6 \text{ cm}} \).