Subtopic: Leaching requirement and salinity control
Question Statement:
An agricultural plot requires a net irrigation depth $D_{net} = 90\text{ mm}$. If the leaching requirement is $LR = 0.10$, the total depth of irrigation water $D_{irr}$ in millimeters that must be applied to satisfy both crop evapotranspiration and leaching is ________ (answer in integer).
Answer Key:
100
Step-by-Step Solution & Explanation
The relationship between total irrigation depth $D_{irr}$, net irrigation requirement $D_{net}$, and leaching requirement $LR$ is:
$D_{irr} = \frac{D_{net}}{1 - LR}$
Given $D_{net} = 90\text{ mm}$ and $LR = 0.10$:
$D_{irr} = \frac{90}{1 - 0.10} = \frac{90}{0.90} = 100\text{ mm}$