I used these slides for a presentation about irrigation water quality at the Sustainable Turfgrass Management in Asia 2017 conference. I then showed various calculations of the daily soil water balance.

calculate the leaching requirement (LR). Second, calculate the quantity of water to apply. Let's imagine we have a water with a TDS of 1,500 ppm. And we expect the grass to use (ETc ) 4 mm. How much water is required for irrigation?