Effects of Applying Nitrogen on Yield of Introduced Perennial Summer Grass Cultivars in Oklahoma

A single-location, three-year study (2008-2010) was conducted near Ardmore, OK, to determine the effects of five nitrogen rates (0, 50, 100, 200 and 300 lb N/acre) on yield of seven varieties of bermudagrass and two varieties of old world bluestem (OWB). Four seeded and three vegetatively propagated (hybrid) bermudagrass varieties were tested. Forage yields were affected by N rate, variety, and year. The effect of N rate depended on year. B Dahl OWB outyielded Plains OWB at all N rates except 0 lb N/acre. Common, Cheyenne, and Wrangler had similar yields at all N rates except 300 lb N/acre. Blending Giant with Common increased yields over Common alone at all N rates except 50 lb N/acre. Tifton 85 yielded more than any other variety tested at all N rates. Midland 99 and Coastal had similar yield at all N rates. In general, all hybrid bermudagrass varieties tested and B Dahl OWB outyielded seeded bermudagrass varieties and Plains OWB when N rates of 100 lb/acre or more were applied, and hybrid bermudagrass varieties responded more to higher nitrogen rates than seeded bermudagrass varieties or OWB.