Establishment of Warm-Season Putting Green Cultivars with Nitrogen/Potassium Fertilization Ratios.

Bermudagrasses [Cynodon dactylon (L.) Pers. x C. transvaalensis Burt Davy] were primarily used on golf course greens until improved varieties of seashore paspalum (Paspalum vaginatum Swartz) and zoysiagrass (Zoysia spp.), with claims of reduced fertilizer and water usage, became available.  This study was conducted to determine optimum N:K fertilization rates for establishment of selected warm-season cultivars on USGA-specified sand greens.  The effects of 1.2, 2.4, 3.7, and 4.9 g N m⁻² wk⁻¹, and 39.1 g m⁻² polymer-coated N with 1:1, 1:2, 1:3, and 1:4 N/K ratios on ‘TifDwarf’ and ‘TifEagle’ bermudagrasses, ‘SeaDwarf’ seashore paspalum, and ‘PristineFlora’ zoysiagrass [Zoysia japonica Stued. by Zoysia tenuifolia (L.) Merr.] were evaluated.  SeaDwarf and TifDwarf were fastest to establish and PristineFlora was slowest.  Turfgrass cover for 2.4, 3.7, and 4.9 g N m⁻² wk⁻¹ was similar for all grasses, and additional K was not beneficial.  The 2.4 g N m⁻² wk⁻¹ rate was considered optimal for all grasses, as higher N rates did not improve coverage, and increased potential for non-point source pollution.