Divot Resistance of Thick-Cut Sod As Influenced By Pre-Harvest Cultural Practices.

Loss of turf cover via divoting is a primary concern on sand-based athletic playing surfaces. American football is particularly harsh on turf due to players’ size and rapid directional changes. Professional-level fields are frequently replaced with thick-cut sod to produce a safe and immediately playable surface. Turfgrass cultural practices performed at the sod farm warrant study because they play a crucial role in the divot resistance of a recently replaced field.

Experiments were conducted to test the effects of two mowing heights (3.18 or 3.81 cm), two sand topdressing regimes (0.0 or 8.5 kg sand m^-2 split over three applications) and six nitrogen fertilizer programs (ranging from 96-244 kg N ha^-1) on the divot resistance and tensile strength of thick-cut Kentucky bluegrass sod. Sod was harvested 14 months after seeding at a profile thickness of 4.45 cm and evaluated immediately to mimic a newly laid field.

Mowing height and topdressing did not affect divot resistance, but lower N rates produced significantly smaller divots. Plots receiving 146 kg N ha^-1, produced 10% and 27% reductions in divot size compared to plots receiving 195 or 244 kg N ha^-1, respectively. Lower N rates also produced greater below-ground biomass and less thatch than­­ higher N treatments.

Topdressing reduced sod tensile strength by 5%, but all tensile strengths remained well above the minimum harvestable threshold. Adequate tensile strength was maintained under all N rates.

This study suggested nitrogen fertility plays a major role in divot resistance. Topdressing effectively diluted thatch without reducing divot resistance or severely impacting sod tensile strength. Future work should refine N programs and evaluate additional methods of thatch control.