My turfgrass talk column in the May-June issue of GCM China explains how to calculate the amount of irrigation water to apply when one is trying to keep the soil salinity (ECe) from exceeding a threshold value.
The article is available in both Chinese and English.
If the salt is not leached, and accumulates in the soil, the grass can die. To prevent the accumulation of salt, more water than the grass can use must be applied. This causes leaching as the extra water moves below the rootzone, carrying some salt with it.
Good drainage is essential when salt in the irrigation water requires leaching to be done. In the photo below, there is a low area below the drain, and salt accumulation in the soil at that spot prevents grass from growing.
For more on this topic, see the preceding article in this series: Do you know how much salt is in your irrigation water?