Warm-Season Turfgrass Response to Fertilizer Rates and Sources

The objectives of this study were to evaluate effects of natural organic and inorganic fertilizers on various warm-season turfgrass species and to determine if lower rates of natural organic products would provide adequate turfgrass response. Studies were conducted in 2000 and 2001 in two locations in Florida on St. Augustinegrass (Stenotaphrum secundatum Walt. Kuntze) and bermudagrass (Cynodon dactylon x C. transvaalensis Burtt-Davy) cultivars. Each fertilizer product was applied at a low and a high rate throughout the growing season at rates consistent with current University of Florida recommendations for best turfgrass performance and response. In general, highest visual ratings for quality, color, and density were obtained with the higher rate of nitrogen (N), regardless of source, although the low rate of the 27N-1.3P-3.3K fertilizer produced ratings equal to the higher (N) rates from other sources in St. Augustinegrass. Trends were similar for spectral reflectance values, in that best results generally occurred in response to higher N rate, with the exception of the 27N-1.3P-3.3K fertilizer at the lower rate. From the results of this research, it appears that the higher N rate produces better turfgrass responses, regardless of fertilizer source.