Orchardgrass yields more forage mass than mixes containing legumes in silvopasture by subtraction in Wisconsin, USA

Authors: CARTONI CASAMITJANA, STEFANIA - University Of Wisconsin; Duff, Alison; RENZ, MARK - University Of Wisconsin

Submitted to: Agroforestry Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2026
Publication Date: 2/19/2026
Citation: Cartoni Casamitjana, S., Duff, A., Renz, M. 2026. Orchardgrass yields more forage mass than mixes containing legumes in silvopasture by subtraction in Wisconsin, USA. Agroforestry Systems. https://doi.org/10.1007/s10457-026-01456-0.
DOI: https://doi.org/10.1007/s10457-026-01456-0

Interpretive Summary: Silvopasture systems, which include both pasture and tree production, provide both livestock forage and environmental benefits while achieving similar livestock gains to open pastures. However, in the Midwestern USA, little information is available to determine which forage mixtures are appropriate to plant in pastures with trees, and how these mixtures will perform in suppressing weeds and producing livestock forage. We conducted experiments at two locations in Wisconsin to evaluate the establishment and productivity of orchardgrass seeded alone and in grass or grass-legume mixes. We also evaluated how glyphosate application in the fall prior to spring planting affected forage establishment. Glyphosate application reduced the cover of unwanted understory plants and increased the cover of planted grasses 1, 3, and 13 months after planting. Glyphosate application also increased forage mass five times compared to untreated plots 14 months after planting. Orchardgrass seeded alone had greater forage mass and less weed biomass than mixes containing legumes when comparing the total annual productivity of three harvest events. Results suggest farmers should apply glyphosate for weed control int he fall before spring planting, and include orchardgrass as the main component in the silvopasture seed mix.

Technical Abstract: Silvopasture systems can provide forage and environmental benefits while achieving similar livestock daily gains to open pastures. However, in the Midwestern USA, there is little guidance available to select appropriate silvopasture forage mixtures and identify management practices that will suppress weeds and improve forage establishment and production. Experiments were conducted at two locations to evaluate the establishment and productivity of orchardgrass seeded alone or in grass or grass-legume mixes, and the effect of suppressing existing understory vegetation with glyphosate prior to seeding on forage establishment. Glyphosate application reduced cover of unwanted understory plants and increased cover of planted grasses 1, 3, and 13 months after planting. Glyphosate application also increased forage mass five times compared to non-treated plots 14 months after planting. Orchardgrass seeded alone had greater forage mass and less weed biomass than mixes containing legumes when comparing the cumulative total of three within-year harvest events. Results suggest farmers should apply glyphosate for weed control in the fall before spring planting and include orchardgrass as the main component in the seed mix.