Herbicidal Control of Tall Goldenrod in Tall Fescue Hayfields

The addition of several new herbicides labeled for use in pastures or hayfields has led many growers to question their options for weed management. In addition, little is known about the effects of common pasture weeds on total biomass yield or nutritive value in a pasture or hayfield setting. Therefore, field experiments were conducted to evaluate the effect of selected herbicide treatments on tall goldenrod [(Solidago canadensis subsp. altissima (L.)] control and total forage biomass and nutritive values in mixed tall fescue [Lolium arundinacea (Schreb.) S.J. Darbyshire] and legume hayfields. Aminopyralid and aminopyralid plus 2,4-D amine was least effective in controlling tall goldenrod one year after treatment (YAT). Total biomass yields were generally lower in herbicide-treated compared to untreated plots, likely due to the reduction in tall goldenrod and legume density with these treatments. Herbicide-treated biomass yields decreased by an average of 12% 1YAT compared to the untreated control. Nutritive value was also greater in biomass harvested from untreated compared to herbicide-treated forage 1YAT. Results from this study indicate that a variety of herbicide treatments will control tall goldenrod, but that tall goldenrod infestations will not likely decrease the overall yield or nutritive value of the harvested biomass in mixed tall fescue and legume hayfields.