Agronomic responses of tall fescue interseeded with crabgrass and buckhorn plantain

Tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.; TF] is widely used in temperate pastures, but its production and nutritive value may be improved through the interseeding of complementary species such as crabgrass (Digitaria sanguinalis L.; CG) and buckhorn plantain (Plantago lanceolata L.; PL). This study aimed to evaluate the effects of TF in monoculture, TF+CG, TF+PL, and TF+CG+PL during four harvests, focusing on botanical composition, forage mass (FM), and nutritive value in Spring Hill for 2 years. Weed proportion varied throughout the study, but it was lowest (∼20%) in the TF+CG and TF+CG+PL treatments due to the increased proportion of CG observed during the third (24%) and fourth (61%) harvests. In 2022, the TF+PL and TF+CG treatments showed greater FM (2041 and 1958 dry matter [DM] lbs acre⁻¹, respectively). In 2023, the TF+CG+PL treatment recorded the lowest FM (1673 DM lbs ac⁻¹) compared to the other treatments (∼1746 DM lbs acre⁻¹). The fourth harvest showed the greatest FM in 2022 (2372 DM lbs acre⁻¹), and in 2023, both the first and fourth harvests produced the greatest FM (2154 and 1947 DM lbs acre⁻¹, respectively). Overall, there were few differences in nutritive value across treatments; however, the third harvest in both years showed greater crude protein concentration (∼14.9%) and increased neutral detergent fiber digestibility in 2022 (34.7%), with no significant differences in 2023. This study highlights the benefits of interseeding plant species with diverse traits into forage systems to enhance biodiversity. Among the species tested, CG demonstrated superior qualities, including effective weed suppression, greater FM, and improved nutritive value.