Seeded bermudagrass establishment as affected by nitrogen source, rate, and application frequency

Seeded bermudagrass (Cynodon dactylon L.) cultivars are a popular choice for many athletic fields and golf course areas throughout the transition zone and southern United States, but the nitrogen (N) needs to optimize turf coverage are not well defined, and N is likely often applied in excess of actual plant needs. A field study was conducted to compare a controlled release versus readily soluble N-source, total N-rate, and application frequency for seeded bermudagrass establishment on a native soil in the northern transition zone. ‘Rio’ bermudagrass was seeded in June 2020 and 2021 to evaluate eight granular N-fertilizer programs using either ammonium sulfate or polymer-coated urea (PCU). Total N ranged from 0.0 to 6.0 lb N 1,000 ft⁻² among three application frequencies, including applications only at planting (PCU only), or applications at planting with repeat applications every 7 or 14 days following bermudagrass germination. Time to 50% green coverage ranged from 20 to 24 and 23 to 30 days in Year 1 and 2, respectively, and varied by N-program. Applying PCU at planting, 2 lb N 1,000 ft⁻², resulted in similar number of days to 90% green coverage compared with other fertilization programs in both study years but with less overall N and fewer applications. These results indicate that applying more than 3 lb N 1,000 ft⁻² over the first 60 days of establishment provided no measurable benefit in terms of time to maximum turf coverage.