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

Core Ideas Better N management may be required for endophyte‐free fescue forage production. Knifed N may result in greater fescue yield and N uptake, especially when fall applied. Tall fescue yield increases were diminished as N rate approached 150 lb/acre. Average N uptake by fescue was linear to N rate, with ∼ 25% apparent recovery.Nitrogen fertilizer management affects forage production of tall fescue [ Schedonorus arundinaceus (Schreb.) Dumort.], but data are limited regarding yield and N uptake of endophyte‐free tall fescue on claypan soil of the eastern Great Plains. A 3‐yr study was conducted to determine the effects of N fertilizer timing (late fall or late winter), N placement (surface broadcast, spoke [point injection at 3‐inch depth], and knife [subsurface band at 4‐inch depth]), and N rate (0, 50, 100, 150, and 200 lb/acre) on endophyte‐free tall fescue yield and N uptake. Each harvest (E2, R4, and stubble hay) was taken from individual, nonoverlapping subareas in each plot. In Year 1, subsurface placement (knife or spoke) increased yield by up to 34% above N broadcast. In Year 2, applying N in late winter instead of late fall resulted in greater E2 and R4 yields. In Year 3, broadcasting N in late winter or knifing N in late fall improved R4 hay yield, whereas stubble hay yield was >10% greater with knifing because average agronomic N use efficiency was >30% greater. Forage yield increased with low N rates, but the response diminished or plateaued as rates approached 150 lb N/acre. Nitrogen uptake in the R4 and stubble hay harvests, however, increased linearly with N rate, averaging 26 and 23% apparent N recovery, respectively. Nitrogen management for endophyte‐free tall fescue may be complex and variable by year, but yield and N uptake may be increased with knife applications, especially when fall applied.