Nitrogen Management for Seed Production from Endophyte‐Free Tall Fescue Grown on Claypan Soil

Core Ideas Pastures may be replanted with endophyte‐free seed to avoid harmful alkaloids. Better N management may be required for endophyte‐free fescue seed production. Nitrogen fertilizer placement has little effect on endophyte‐free seed production. Fescue seed yield may be maximized with 150 lb N/acre applied in late winter.Nitrogen fertilization affects tall fescue [ Schedonorus arundinaceus (Schreb.) Dumort.] forage production, but data are limited regarding seed production from endophyte‐free tall fescue grown on the claypan soils of the eastern Great Plains. A field study was conducted from fall 1998 to spring 2001 to determine the effects of N fertilizer timing (late fall or late winter), N placement (surface broadcast, spoke [point injection at 3 inches deep], and knife [subsurface band at 4 inches deep]), and N rate (0, 50, 100, 150, and 200 lb/acre) on endophyte‐free tall fescue seed yield, yield components, and harvested seed germination. The soil was a Parsons silt loam (fine, mixed, thermic Mollic Albaqualf), which is a typical claypan soil of the area. Seed yield response to N rates to 100 lb N/acre was similar regardless of application timing, but in two of three years, greater N rates applied in late fall improved seed production to about 400 lb/acre. Even though all components of seed yield responded to N fertilization, panicles/ft 2 had the highest correlation ( r = 0.83) with seed yield and showed greater response in 1999 to N applied in late fall at a higher rate compared with fewer panicles/ft 2 at lower rates of N applied in late winter. The effect of N fertilization on germination of harvested seed was small. Fertilizer N placement had little effect on measured variables. In summary, increasing N rate to 150 lb/acre and applying it in late winter has the potential to maximize production of endophyte‐free tall fescue seed.