Yield, quality, and persistence of grazing- and hay-type alfalfa under three harvest frequencies

Producers in the lower Midwest often plant grazing-type alfalfa (Medicago sativa L.) cultivars assuming they can withstand frequent hay harvests. However, little research has examined the long-term effects of frequent hay harvests on grazing-type compared with hay-type alfalfa. Our objective was to determine how cultivar-type and harvest frequency change long-term alfalfa yields, quality, and stand persistence. 'Alfagraze' (grazing-type), 'Pioneer 5373' (modern, multipest resistant hay-type), and 'Cody' (older hay-type) alfalfa were seeded on 1 Apr. 1994, near Mt. Vernon, MO. Cultivars were main plots, and four, five, or six harvests before 15 September (42, 34, and 28 d between harvests, respectively) were subplots in a randomized complete block in a split-plot arrangement. Cumulatively, over 5 yr, Pioneer 5373 produced 6% (2.8 Mg ha(-1)) more forage than Alfagraze and 10% (5.0 Mg ha(-1)) more than Cody. Alfalfa harvested four times yielded 7% (0.8 Mg ha(-1)) more per year than when harvested five times, and 28% (3.1 Mg ha(-1)) more than when harvested six times. Alfagraze and the hay-types yielded equally when harvested six times. Alfagraze usually had equal or lower detergent fiber, and equal or greater crude protein (CP) concentrations than other cultivars. Harvesting more frequently improved forage quality but had little impact on plant density. We concluded that a grazing-type, like Alfagraze, does not show a yield or persistence advantage over a modern hay-type under frequent hay harvest regimes in the lower Midwest. However, the grazing-type used in this study often had superior forage quality.