Effect of nitrogen rate, application timing and source on productivity of sodseeded annual ryegrass

Ryegrass (Lolium multiflorum Lam.) is often seeded into warm-season perennial grass swards to extend the grazing season but there is minimal information documenting the response of sodseeded ryegrass to N fertilization, This 3-year field study was conducted to evaluate the effect of N source, N rate, and time of application on forage production from sodseeded ryegrass, Ammonium nitrate and urea were used to supply 50, 100, and 200 Ib N/acre in fall and late winter. Plots receiving each N rate from each source in any one season received 50 Ib N/acre in the other season from ammonium nitrate, Treatments receiving no N at either time or no N in one season and 50 Ib N/acre in the other season were included. Dry forage production in the early season, prior to winter N application, was variable over years and exceeded .5 ton/acre in only one year and then only when at least 100 Ib N/acre had been applied. Forage production during late winter and early spring was more responsive to N application and considerably greater than early season production. The resulting total annual production ranged from approximately .5 ton/acre when no N was applied to over 2 ton/acre when total applied N exceeded 150 lb/acre. Results indicate sodseeded ryegrass can produce a significant amount of forage in late winter and early spring but even high fall N rates will not greatly enhance early season production.