Nitrogen rate required for acceptable St. Augustinegrass and associated nitrate leaching

Travis W. Shaddox, J. Bryan Unruh, Laurie E. Trenholm, Pauric C. McGroary, John L. Cisar

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The recommended N rates for St. Augustinegrass (Stenotaphrum secundatum [Walt.] Kuntze.) vary in Florida. This research, conducted in Fort Lauderdale, Citra, and Jay, FL, (2006– 2008), aimed to determine the minimum N rate necessary for acceptable St. Augustinegrass and to determine the influence of N and irrigation rate on NO3–N leaching. Urea was applied in Fort Lauderdale, Citra, and Jay at 98, 196, 294, and 588; 49, 196, 343, and 490; and 49, 98, 196, and 294 kg N ha-1 yr-1, respectively, based on best management practices. Irrigation was 2.5 mm d–1 and 13.0 mm three times weekly in Fort Lauderdale; 13 mm twice weekly and 26 mm wk–1 in Citra and Jay. In Fort Lauderdale and Jay, lower than recommended N rates mostly produced acceptable turfgrass. Applications of 196 kg N ha-1 (Fort Lauderdale) and 98 kg N ha-1 (Jay) were the lowest rates producing acceptable turf. In Citra, 65% more N was required for acceptable turf than the recommended minimum . Leaching from all N rates was similar, except when N rates exceeded recommendations or when turfgrass exhibited herbicide stress. The high irrigation rate doubled NO3–N leaching compared to the low rate in Fort Lauderdale; irrigation frequency had no influence on leaching in Citra or Jay. The predicted minimum N rate for acceptable turf in Fort Lauderdale was <98 kg N ha-1 yr-1 (lower than in Citra; more than in Jay). In stressed turf, additional N conferred little benefit to quality and increased leaching.

Original languageEnglish
Pages (from-to)439-451
Number of pages13
JournalCrop Science
Issue number1
StatePublished - Jan 2016

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ASJC Scopus subject areas

  • Agronomy and Crop Science


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