Consider a maize field of 3 hectares. The crop requires 600 mm of water over the growing season and the irrigation system has an efficiency of 70 %. Calculate the volume of water in cubic metres that must be supplied by the irrigation system.

Step-by-step solution

1. Convert field area to square metres: $3$ ha = $3\times 10,000=30,000$ m${}^2$.
2. Convert water requirement to metres: $600$ mm = $0.6$ m.
3. Compute required volume: $0.6\times 30,000=18,000$ m${}^3$.
4. Adjust for 70 % efficiency: $\frac{18,000}{0.70}=25,714.29$ m${}^3$.
5. Round to nearest whole number: $25,714$ m${}^3$.

Concept tested: Irrigation water calculation

Published 4 October 2026 · How this solution was prepared and checked