Establishment and Production of Alfalfa in Existing Bermudagrass Pasture.

Alfalfa (Medicago sativa L.) planted into existing bermudagrass [Cynodon dactylon (L.) Pers.] pasture may provide N through N fixation, improve forage nutritive value and intake, and extend the grazing season. However, legumes generally have poor seedling vigor and can be difficult to establish. The objectives of this study were aimed at improving alfalfa seedling vigor (establishment) and were to determine the effects of planting date (September, October, and February), seedbed preparation (clean tilled, hayed, and hayed + glyphosate), and fungicide and insecticide seed treatments (UTC, insecticide [Cruiser®], fungicides [Apron® and Maxim®], and fungicide + insecticide mixtures [Cruiser Maxx™, Cruiser + Apron, and Cruiser + Apron + Maxim at the maximum labeled rate] on alfalfa seedling density, forage production, and botanical composition of ‘Alfagraze’ 600RR alfalfa planted into existing ‘Midland 99’ bermudagrass sod at Burneyville, OK in 2012-13 and 2013-14. Hayed and hayed + glyphosate resulted in more alfalfa seedlings that clean tilled when planted in October. More seedlings were present in October and February plantings when insecticide was included. Greatest total forage yield of September planting was obtained in the hayed seedbed (99% bermudagrass), while hayed + glyphosate resulted in the least yield but greatest alfalfa contribution (82%). Alfalfa was the greatest contributor (75%) in the clean tilled seedbed in October planting, while bermudagrass was the greatest contributor in hayed (86%) and hayed + glyphosate (80%). February planting limited alfalfa establishment in all seedbeds (~7% alfalfa). Seed treatment was only effective in October planting, when there was some yield advantage with insecticide. Seedbed preparation and planting date had greater impact on alfalfa establishment and yield than fungicide and insecticide. Future research will evaluate the potential of alfalfa interseeded in bermudagrass under grazing.