Comparing forage yield, quality, and weed pressure in alfalfa monocultures and alfalfa-grass mixtures in the Midwest

Authors: Pope, Julia; Gamble, Joshua; Duff, Alison

Submitted to: Forage Focus
Publication Type: Trade Journal
Publication Acceptance Date: 4/20/2026
Publication Date: 5/15/2026
Citation: Pope, J.K., Gamble, J.D., Duff, A. 2026. Comparing forage yield, quality, and weed pressure in alfalfa monocultures and alfalfa-grass mixtures in the Midwest. Forage Focus. May 2026, pages 6-7..

Interpretive Summary: Alfalfa acreage in the Midwest has declined significantly over the past 25 years, in part due to farmer concerns about winter kill and stand longevity. Alfalfa-grass mixtures may be a solution in northern climates, where inclusion of grass varieties may bolster yield, suppress weeds, and improve stand persistence. We compared yield, forage quality, and weed pressure in alfalfa monocultures and alfalfa-meadow fescue bicultures at the field scale in Wisconsin (WI) and Minnesota (MN). The WI fields were managed in a conventional dairy forage system, while the MN fields were managed in an organic dairy forage system. In WI, forage yield was significantly higher in the biculture field for the second, third, and fourth cuts in 2024, and in the third and fourth cuts in 2025. At the MN site, the biculture yield was significantly lower for the first cut in both years, but not significantly different for any other harvests. The proportion of weeds was significantly lower in the biculture fields across all cuttings, years, and sites. Forage quality analyses are ongoing, but initial results show that for the WI fields, aNDF values were higher in the biculture field only in the third and fourth cuttings, while CP was not significantly different between fields across cuttings. This study will continue through 2026, with additional assessments to include soil health comparisons in the monoculture and biculture fields, as well as an evaluation of how increasing proportions of meadow fescue affect forage quality in the biculture harvest.

Technical Abstract: Alfalfa acreage in the Midwest has declined significantly over the past 25 years, in part due to farmer concerns about winter kill and stand longevity. Alfalfa-grass mixtures may be a solution in northern climates, where inclusion of grass varieties may bolster yield, suppress weeds, and improve stand persistence. We compared yield, forage quality, and weed pressure in alfalfa monocultures and alfalfa-meadow fescue bicultures at the field scale in Wisconsin (WI) and Minnesota (MN). The WI fields were managed in a conventional dairy forage system, while the MN fields were managed in an organic dairy forage system. In WI, forage yield was significantly higher in the biculture field for the second, third, and fourth cuts in 2024, and in the third and fourth cuts in 2025. At the MN site, the biculture yield was significantly lower for the first cut in both years, but not significantly different for any other harvests. The proportion of weeds was significantly lower in the biculture fields across all cuttings, years, and sites. Forage quality analyses are ongoing, but initial results show that for the WI fields, aNDF values were higher in the biculture field only in the third and fourth cuttings, while CP was not significantly different between fields across cuttings. This study will continue through 2026, with additional assessments to include soil health comparisons in the monoculture and biculture fields, as well as an evaluation of how increasing proportions of meadow fescue affect forage quality in the biculture harvest.