Finer topdressing sand affects creeping bentgrass quality and surface characteristics

Abstract

Routine application of topdressing sand is widely practiced to manage putting green surfaces. Topdressing with finer sand and/or at minimal rates can enhance incorporation, greatly reducing the concerns of interference. A 7-year field study investigated the effects of topdressing and cultivation practices on turf quality and surface characteristics of creeping bentgrass (Agrostis stolonifera L.) grown on a sand-based rootzone. A 3 × 2 × 2 factorial design evaluated sand size (medium-coarse, medium-fine, and fine-medium), rate of topdressing during mid-season (0.24 or 0.49 kg m⁻² every 10–14 days), and cultivation (hollow tine cultivation [HTC] plus backfilled with medium-coarse sand or noncultivated). Sand size and topdressing rate significantly affected turf quality, surface volumetric water content (VWC), and surface hardness, with their effects dependent on cultivation. Without HTC, VWC increased as the topdressing sand size became finer. However, when HTC was applied, VWC was not increased by topdressing with medium-fine sand during any year. The practice of HTC also offset the effect of fine-medium sand increasing VWC during the first 4 years, but not Years 5 through 7. Therefore, caution is needed when considering fine-medium sand for topdressing putting greens. Additionally, after 5 years of treatment, the lower topdressing rate led to a wetter surface compared to the higher rate in the absence of cultivation, but not when HTC was applied. The major drawback of HTC was disruption of the turf surface, which resulted in better turf quality on noncultivated plots throughout the trial.