Removal of Coarse Sand from Topdressing Applied to Putting Green Turf.

Sand topdressing of putting greens during the season is often limited to avoid interference to play and excessive dulling of mower blades. This study evaluated the effects of eliminating coarse particles from topdressing sand on the surface wetness and turf quality of a creeping bentgrass (Agrostis stolonifera) turf. This trial was initiated in May 2016 on a 19-month-old ‘Shark’ creeping bentgrass maintained at 2.8-mm on a sand-based root zone. A 3 x 2 x 2 factorially arranged randomized complete block design with four replications included the factors of sand size (medium-coarse, medium-fine, fine-medium), quantity of mid-season topdressing (2,440 and 4,880 kg ha-1 every 2 weeks), and cultivation (non-cultivated or core cultivation plus backfill). Two non-topdressed controls (at both levels of cultivation) were included for comparisons resulting in 14 total treatments. Turf quality was visually rated June through October. Volumetric water content of the surface 0- to 76-mm depth zone was monitored routinely. Core samples were collected before and one-year after treatment initiation to characterize the thickness of the thatch-mat layer and content of sand and organic matter. Mower clippings were collected from each plot to determine the quantity and particle size distribution of sand collected during mowing. Better turf quality was observed on topdressed plots than non-topdressed plots, regardless of sand size or topdressing rate. Medium-coarse and medium-fine sand produced a drier surface compared to plots topdressed with fine-medium sand; however, this sand size effect on surface wetness frequently was not observed in cultivated plots (sand size factor interacted with cultivation factor). The mat layer was thickest in topdressed plots compared to the nontopdressed plots and the greater topdressing rate had a thicker mat layer than the low topdressing rate. Data on