Annual Ryegrass Response to Increased Seeding Rate and Nitrogen Fertilization

An experiment of nitrogen fertilization and seeding rates of overseeded annual ryegrass (Lolium multiflorum Lam.) into bermudagrass [Cynodon dactylon (L.) Pers.] on early fall and total forage production was conducted. A 3 × 4 factorial arrangement of 1×, 2×, and 3× the recommended annual ryegrass broadcast rate of 30 lb/acre and 0, 25, 50, and 75 lb N per acre applied in the fall and spring for a total of 0, 50, 100, and 150 lb N per acre were arranged in a randomized complete block experimental design in the 2004-2005 (2005) and 2005-2006 (2006) seasons. Across treatments, total annual ryegrass yields ranged from 1998-3895 and 2607-3406 lb/acre in 2005 and 2006, respectively. A N effect (P < 0.001) occurred at all harvests in 2005, but not 2006. Total yield increased (P < 0.001) with N in 2005, but not 2006 (P = 0.0502). Seedling density increased (P < 0.05) in proportion to seeding rate. Cumulative yield of the first two harvests was 14% to 19% of total and were greater (P < 0.05) at 2× and 3× compared to the 1× seeding rate in 2005, but not in 2006 (P = 0.94). Seeding rate had no effect (P = 0.81 and 0.30 for 2005 and 2006, respectively) on total yields. Increasing annual ryegrass seeding rates is not a reliable strategy for increasing early season or total forage production.