Agricultural Drainage and Salinity

The Leaching Requirement ($LR$) to maintain root zone salinity below a threshold drainage salinity $EC_{dw}$ is given by:

Options:

• (A) $LR = \frac{EC_{iw}}{EC_{dw}}$
• (B) $LR = \frac{EC_{dw}}{EC_{iw}}$
• (C) $LR = EC_{iw} \times EC_{dw}$
• (D) $LR = EC_{dw} - EC_{iw}$