The Phosphorus Saturation Index Revisited

Phosphorus runoff and leaching to surface water is a growing concern. In this Update, we take a look at the Phosphorus Saturation Index, a measurement that can help you monitor and improve soil phosphorus management. The bottom line is that current phosphorus sufficiency guidelines may be too high.

The term phosphorus saturation index (PSI), sometimes also known as the phosphorus saturation ratio (PSR), has been used to determine the risk of phosphorus surface runoff or phosphorus leaching through the soil…