A soil sampling recommendation

Our standard recommendation is to sample turfgrass soils to a 10 cm (4 inch) depth. That's a reasonable depth to represent the turfgrass rootzone.

Soil pH changes by depth. So does soil organic matter (SOM). In a sand rootzone, the cation exchange capacity (CEC) is largely controlled by the SOM, so the CEC and consequently the nutrient cations Ca, Mg, and K also are at different levels by depth. Then there are nutrients like P that are relatively immobile in…