Long‐term effects of low N rates on St. Augustinegrass cultivars

Current recommended nitrogen fertilization rates for St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze] in South Florida range from 4 to 6 lb N per 1,000 ft2 yr, applied throughout the year. Nevertheless, strict fertilizer ordinances are being passed by multiple counties Florida, setting limits amount of that can be turfgrass areas, and establishing summer blackout periods applications; hence, there is a need identify minimum sustain quality. A 4-yr study was conducted at University Florida's Fort Lauderdale Research Education Center assess quality four cultivars (‘CitraBlue’, ‘Floratam’, ‘Palmetto’, ‘Raleigh’) grown on Hallandale fine sand (siliceous, isohyperthermic Lithic Psammaquents) fertilized either 2.5 or 5 yr. Plots were evaluated monthly visual quality, yearly genetic color, leaf texture, spring green-up, density. CitraBlue had highest Differences rarely detected among other three cultivars. Nitrogen an effect only density, suggesting with 3.4% organic matter could managed less than currently without detrimental effects.