Effects of Nitrogen Rate and Mowing Height on Six Varieties of St. Augustinegrass.

St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze] is a popular turfgrass species used for residential and commercial landscapes throughout the Southeastern United States. ‘Captiva’ is a new cultivar now available and marketed for use in Florida. There is very little information available regarding the management of Captiva or how it compares to older, better known cultivars. A field experiment was conducted in 2007 and 2008 to evaluate the effects of nitrogen rate and mowing height on three St. Augustinegrass cultivars (Captiva, ‘Floratam’, and Seville’). The treatments were arranged in a strip split plot design with three replications plant in a Candler Sand (Hyperthermic, Uncoated, Typic Quartzipsamments). The cultivars were split into two mowing heights (6.4 and 8.9 cm) applied as strips across cultivars. Within each mowing height, fertility treatments consisted of 97.6, 195.2, and 292.8 kg N ha^-1 yr^-1 applied as 24.4, 48.8, and 73.2 kg N ha^-1 in 60 day intervals. Plots were rated visually using a one to nine scale for color, density and turf quality from April to Dec. 2007. Ratings occurred on a monthly basis. In 2007, Floratam maintained acceptable ratings (> 5) for color, density and turf quality for all months rated and at all nitrogen levels. Seville and Captiva maintained acceptable color, density and turf quality for all months at the 97.6 kg N ha^-1 yr^-1 rate except for color and density during June. Higher N-rates resulted in a loss of color and turf quality late in the growing season for both Seville and Captiva. 2007 results indicate that 97.6 kg N ha^-1 yr^-1 can provide acceptable turfgrass performance for the three cultivars studied in north-central Florida.