Subtopic: Leaching requirement and salinity control
Question Statement:
The electrical conductivity of irrigation water is $EC_w = 1.5\text{ dS/m}$. The crop can tolerate an electrical conductivity of the saturation extract up to $EC_e = 6.0\text{ dS/m}$ without yield reduction. Using the FAO equation $LR = \frac{EC_w}{5 EC_e - EC_w}$, the leaching requirement ($LR$) expressed as a percentage is ________ (round off to 1 decimal place).