99 Managing alfalfa-bermudagrass mixtures in the Southeastern U.S. to establish livestock grazing recommendations

Abstract

Abstract Recently there has been interest in interseeding high-quality legumes, like alfalfa, into existing bermudagrass stands as a step towards improving forage, animal, and ecosystem stability in the Southeast. Current work evaluating these mixtures has been focused on management and production of stored forages (i.e. dry hay/baleage), and limited work has evaluated the use of alfalfa-bermudagrass mixtures under grazing conditions. It has been noted that both grazing intensity and frequency impact overall stand production over time. The objective of this research is to evaluate the effect of harvest height and frequency of newly established alfalfa interseeded into an existing bermudagrass stand, and begin to develop grazing recommendations for management of these mixtures. In 2018, 36 alfalfa-bermudagrass plots were established at 4 locations across Alabama (Crossville, Shorter) and Georgia (Watkinsville, Tifton), using a randomized complete block design with four replications at each location. Alfalfa varieties were selected for suitability to location and were either ‘Bulldog 505’ or ‘Bulldog 805’ interseeded into existing hybrid bermudagrass sods. Treatments included combinations of harvest frequency (2, 4, or 6 wk) and harvest height (2, 4, 6 inches), and plots were evaluated for their influence on sward yield, persistence, stand density, botanical composition, nutritive value, and change over time. In Georgia, the ‘Bulldog 805’ treatment harvested every 6 weeks at 6 inches had the greatest yield on average (2,453 kg/ha), while ‘Bulldog 505’ treatment harvested every 2 weeks at 6 inches had the lowest yield on average (382 kg/ha) during the 2018 growing season. Additionally, botanical compositions showed that the 6 week, 4-inch had the greatest proportion of alfalfa throughout the growing season, while alfalfa proportions decreased across the growing season in the 2 week, 2-inch harvest treatment. This study is supported by funding from the USDANIFA-Alfalfa Forage Research Program (2017)