Glyphosate Timing Effects on Establishment of Sod-Seeded Legumes and Grasses

Sod-seeding establishment of small-seeded legumes and grasses has great potential for increasing forage production on previously non-tillable lands. However, consistently successful stand establishment has been difficult to achieve via sod-seeding. Even when adequate stands are obtained, they often lack the vigor associated with conventional establishment. A delay between the spraying of a non-selective chemical for sod control and seeding with a minimum-till drill has been suggested to improve sod-seeding stand establishment. We conducted two field experiments to determine the optimum time interval needed between spraying glyphosate [N-(phosphonomethyl) glycine] and sod-seeding various grass and legume species with minimum-ti11 drills. The soils were classified as Cumulic Haploborolls and Ustic Tomfluvents in the first experiment and Udic Haploborolls and Typic Eutrochrepts in the second. A 14 day interval between spraying glyphosate and sodseeding alfalfa (Medicago sativa L.), alsike clover (Trifolium hybridum L.), and tall fescue (Festuca arundinacea Schreb.) with either the John Deere Powr-till drill or the Melroe 701 No-till drill was needed for adequate establishment at Laramie, Wyoming in 1978. In 1979, a 7 to 14 day spray-plant interval was needed for adequate establishment of alfalfa, alsike clover, creeping meadow foxtail (Alopecurus mundinaceus Poir.), and meadow bromegrass (Bromus biebersteinii Roem. & Schult.) when seeding with the John Deere drill. When seeding with the Melroe drill in 1979, no differences among spray-plant intervals were obtained for the same species. At Kalipell, Montana in 1978, a 28 day delay between spraying glyphosate and sod-seeding alfalfa with the John Deere drill was needed for adequate establishment; whereas ladino clover (Trifolium repens L.) required a 14 day interval between spraying and seeding. In 1979 at Kalispell, a 28 day spray-plant interval was needed for adequate establishment of alfalfa. Ladino clover establiihment was very poor for all spray-plant intervals. Inadequate legume establishment was associated with slug (Agriolimax reticulatum Müller) predation. Spraying 28 days prior to seeding allowed sufficient time for grass desiccation. This permitted sunlight to penetrate the canopy which dried out the furrow thereby providing a less favorable slug environment.