Glyphosate Timing Effects on Establishment of Sod‐Seeded Legumes and Grasses¹

Abstract

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‐till 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.

Comparison of Conventional and Minimal Tillage for Low-Input Pasture Improvement

“…2), and glyphosate [N-(phosphonomethyl) glycine] or paraquat (1,1'-dimethyl-4,4'bipyridinium) are the herbicides most commonly used for suppression or destruction of existing pasture. Generally glyphosate was more effective than paraquat and applications 14 to 30 days prior to planting were more effective than those made within a week before planting, or post-planting (27,62,93). Emergence of crops sown by minimal tillage into pasture without prior herbicide application averaged 66% of that obtained when minimal-tillage seeding was preceded by herbicide application, when the most effective herbicide treatments were considered (Fig.…”

“…This damage may be more acute in crops sown by minimal tillage than with conventional cultivation (33,57,74,94), however, Ellis et al (36) noted that the incidence of damage by frit fly ( Oscinella frit L.) was greater in conventional than in no‐till seedings, and attributed this to a dilution of predator effect over both resident and establishing plants. Trimming, desiccation, or burning of crop residues associated with minimal‐tillage seeding will provide a less favorable environment for mollusks, and may enhance establishment (57,93). Fenner (39) observed that the vulnerability of seedlings to snail ( Helix aspersa Müller) predation decreased rapidly with time and increase in seedling size; therefore conditions that slow seedling growth are likely to increase snail predation and reduce seedling survival.…”

“…Pest and disease problems at establishment. Predation by a range of insect (15,74,98) or mollusk (5,15,33,57,93,98) pests may result in less effective establishment and reduced yield of newly-sown forages. This damage may be more acute in crops sown by minimal tillage than with conventional cultivation (33,57,74,94), however, Ellis et al (36) noted that the incidence of damage by frit fly (Oscinella frit L.) was greater in conventional than in no-till seedings, and attributed this to a dilution of predator effect over both resident and establishing plants.…”

Effects of sowing date, placement of seed, vegetation suppression, slugs, and insects upon establishment of no‐till alfalfa in orchardgrass sod†

“…Timing of herbicide spraying was considered critical by Welty et al (1981). They obtained best results in reducing plant competition by spraying glyphosate 28 days before sowing.…”

Alfalfa establishment without tillage as influenced by insecticide and vegetation suppression

“…Paraquat (1,1-dimethyl-4, 4-bipyridinium chloride) and glyphosate (Af-(phosphonomethyl) glycine) have been shown to be effective herbicides for control of existing vegetation before sowing (Taylor et al, 1969;Moshier and Penner, 1978;Welty et al, 1981;Martin et al, 1983). Important factors that may determine degree and comparative success of herbicide include date and rate of herbicide application, and whether herbicide is band or broadcast sprayed.…”