Impact of cool‐season legume interseedings or timed nitrogen applications on yield and nutritive value of annual ryegrass

Abstract

AbstractAnnual ryegrass (Lolium multiflorum Lam.) is an essential part of winter grazing systems in the southern United States. Because of an increase in nitrogen (N) cost, producers are considering decreasing fertilizer application rates while incorporating forage‐type legumes as part of their grazing management system. The objectives of this study were to determine optimum management practices including N fertilizer application rate and timing and the incorporation of legume species and to assess changes in yield and nutritive value. ‘Marshall’ ryegrass was planted in a prepared seedbed at a rate of 25 lb pure live seed acre–1 in the fall of 2008, 2009, and 2010. The experiment included nine N fertilization regimes such as the fall and spring application of ammonium nitrate (34‐0‐0). Along with an untreated check (UC), N applications (lb N acre−1 in fall, spring, or both) included the following: 25F‐0S, 0F‐25S, 25F‐25S, 50F‐0S, 0F‐50S, 50F‐25S, 25F‐50S, and 50F‐50S lb N acre–1. Along with fertilization treatments, annual and perennial clover (Trifolium spp.) and hairy vetch (Vicia villosa Roth subsp. villosa) were included in the study. Yields were significantly lower during the 2009–2010 season. Higher yields were observed in the 2010–2011 season when warmer temperatures occurred in the spring. Nitrogen applications produced a slight yield advantage than the clover species. The 75 lb N acre–1 (25F‐50S) application produced the highest forage mean yield. Clover treatments had a higher yield than the UC.