EFFECTS OF SLOW-RELEASE FERTILIZERS ON TURF QUALITY IN A TURF MIXTURE

A 2-year field study was conducted to determine the influence of the timing of application and different slow release nitrogen (N) sources with different nitrogen rates on the growth and quality of a turfgrass mixture. Three different timings were used for nitrogen application: annually, once every 3 months, and once every 6 months. Three nitrogen sources (ammonium nitrate and two slow-release fertilizers, Entec and Osmocote) were used in the trial. Annually applications were carried out at rates of 0 (control) g m(-2), 30 g m(-2), 60 g m(-2), 90 g m(-2). Results of this study showed that both slow-release fertilizers had significantly higher ratings of color and quality and significantly higher clipping yields compared with the control (ammonium nitrate) during the fall and winter seasons. During the other seasons, the slow-release fertilizers produced equal, slightly higher or slightly lower color and quality ratings and clipping yields, compared with the control. It should be noted that an acceptable color rating and turf quality were obtained in the fall and winter seasons with 60 and 90 g N m(-2) yr(-1) of slow release fertilizers.