Thursday, November 5, 2009: 8:30 AM
Convention Center, Room 403-404, Fourth Floor
‘Empire’ Zoysiagrass (Zoysia japonica Steud.) and ‘Floratam’ St. Augustinegrass (Stenotaphrum secundatum Walt. Kuntze) were established as sod in the spring of 2005 and 2008 (Empire) and 2006 and 2007 (Floratam) at the University of Florida Plant Science Research and Education Unit in Citra, FL. Nitrogen (N) treatments were applied the day that sod was planted at rates of 24.5, 49, and 98 kg N ha-1 as quick release urea. Half of the plots received an additional N treatment at the same rates 30 days after planting. Two irrigation treatments were imposed; one was a graduated program where applications were reduced and amount of water increased over a 3-wk. period and the other treatment applied 1.3 cm irrigation daily. Experimental design had irrigation treatments nested within blocks with N treatments randomized within. There were three replications. Evaluations taken included total nitrate leached, turf visual quality and color, and multispectral reflectance. Leachate samples were collected and frozen until analysis from 2005-2007. In 2008, samples were acidified and sampled within 28 days. Nitrate leached from Empire ranged from 4865 to 8951 mg m-2 over the 60-day evaluation period, or 31 to 70% of the applied N. Nitrate leached from Floratam ranged from 1921 to 5152 mg m-2 over the 60-day evaluation period, or 37 to 54% of the applied N. Irrigation treatments did not generally result in differences in nitrate leaching. Visual quality ratings differed due to N rate on some evaluation dates, but were above a minimal acceptance level of 6.0 at all N rates. From the results of this experiment, we would recommend that no N fertilizer be applied to newly established turf for the first 30-60 days following sodding.