Effect of Nitrogen Rate on Turfgrass Quality among Five Cultivars of St. Augustinegrass

Organic nutrient sources for turfgrass fertilization continue to gain acceptance in lawn care practices.  St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kutze] is a common lawn grass of the southern United States.  The goal of this study is to measure growth responses of five St. Augustinegrass cultivars fertilized with organic nutrient sources while implementing water conserving practices.  The St. Augustinegrass cultivars Raleigh, Delmar, Captiva, Palmetto, and Amerishade were installed in a randomized complete block design in fall 2012.  Research plots were installed in Huntsville, Texas on a Falba fine sandy loam (fine, montmorillonitic, thermic Typic Albaqualfs).  An organic fertilizer source will be applied at a rate of 100, 200, and 300 kg N ha^-1 per year split over three applications with the first application in April 2014.  Plots are irrigated by a sprinkler system using seasonal crop coefficients, minus rainfall, for spring, summer, and fall of 0.5, 0.6, and 0.7, respectively. Plots are mowed as needed to maintain a cutting height of 7.6 cm.  Visual ratings of color and density, clipping yield, and soil chemical characteristics will be presented.