How is the diversion water requirement calculated?

The calculation of the diversion water requirement is fundamentally about determining how much water needs to be diverted to meet the needs of the crops while accounting for factors such as losses that occur during irrigation. The choice reflecting the subtraction of application losses from the farm water requirement accurately captures this concept.

The farm water requirement represents the total amount of water that crops need to grow effectively. However, not all the water that is applied will be used by the plants due to losses that occur through evaporation, deep percolation, or runoff during the irrigation process. Therefore, by subtracting the application losses from the farm water requirement, one can effectively determine the actual volume of water that needs to be diverted in order to meet the crop’s needs.

Understanding this calculation is crucial for efficient water management in agricultural practices, ensuring that sufficient water is available for crops while minimizing waste. Other options do not reflect the correct methodology for calculating the diversion water requirement as they either disregard the importance of accounting for application losses or involve unrelated factors such as rainfall or soil moisture.