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Nitrogen Management Strategies for Warm-Season Turfgrass in the Southern United States
Abstract
There is growing importance in developing more sustainable agronomic management strategies and enhancing resource use efficiency in warm-season turfgrass systems. Two multi-year field studies were conducted in College Station, TX to 1) Evaluate St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) cultivar performance under low-input regimes and 2) Determine best practices for late-season nitrogen applications in hybrid bermudagrass (Cynodon dactylon x C. transvaalensis Burt. Davy) turf systems. The first study focused on evaluating the responses of St. Augustinegrass cultivars 'ProVista', 'Raleigh', 'Palmetto', and 'Floratam' to standard (14.7 g N m^-2 yr^-1) and reduced (4.9 g N m^-2 yr^-1) nitrogen (N) inputs as well as standard (7 day) and infrequent (14 day) mowing regimes. The study was conducted under a 14-d restricted irrigation frequency. Results of the study showed that Floratam maintained the highest turf quality and percent green cover during mid-summer months while ProVista showed the darkest green color across all rating dates. Shoot elongation rates differed among cultivars, with ProVista showing the least vertical elongation of all cultivars. Despite this, all St. Augustinegrass cultivars maintained adequate turf quality and green cover under the reduced inputs and there was no benefit to applying more than 4.9 g N m^-2 yr^-1. In the second study, effects of late-season nitrogen application timing (early fall, mid fall, late-fall, fall split applied, winter spoon feeding) approaches and N source (urea, methylene urea, urea formaldehyde, and 50/50 combination of urea/methylene urea) on winter color and spring green-up were evaluated. Results showed that Urea or 50/50 (blend of Urea/MU) generally provided superior bermudagrass quality, color, and spring shoot N compared to other N sources. The Winter Spoon-Feeding timing regime of monthly, low-rate N applications also led to higher overall quality and color throughout winter than the single, higher-rate fall applications. Collectively, these data offer guidance to turf managers for improving performance and environmental sustainability of managed turfgrass systems.
Subject
NitrogenCitation
Cherry, Graeme Douglas (2023). Nitrogen Management Strategies for Warm-Season Turfgrass in the Southern United States. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /199993.