Evaluation of sainfoin (Onobrychis viciifolia) for forage yield and persistence in sainfoin–alfalfa (Medicago sativa) mixtures and under different harvest frequencies

Abstract

Condensed tannins in sainfoin (Onobrychis viciifolia) improve forage digestion and reduce the risk of ruminant bloat caused by grazing alfalfa (Medicago sativa). The objectives of this study were to evaluate the forage dry matter yield (DMY) and persistence of newer sainfoin cultivars in mixtures with alfalfa, and to determine the impact of harvest frequency on the persistence of sainfoin. Sainfoin cultivars ‘AAC Mountainview’, ‘AAC Glenview’, ‘Delaney’, ‘Shoshone’, and six experimental populations were compared with ‘Nova’ and ‘Melrose’ at Lanigan, SK, from 2016 to 2018. Field plots were seeded in either monocultures of sainfoin at 33 kg·ha−1 or sainfoin–‘AC Grazeland’ alfalfa mixtures at 16:9 kg·ha−1 in alternate rows. Forage DMY was greater (P = 0.001) in mixtures than in sainfoin monocultures in all harvests. The proportion of sainfoin in mixtures at Cut 1 declined from 4.1% to 1.3% of total DMY from 2016 to 2018, and 19.0% to 4.8% in Cut 2, which was less than the recommended level to eliminate ruminant bloat risk. A second field trial was established in 2017 to compare responses of ‘AAC Mountainview’, ‘Nova’, and ‘Shoshone’ sainfoin under one-, two- or three-harvest frequencies in 2018 and 2019. The increase of harvest frequency did not reduce sainfoin stand (%). Stand percentage of ‘AAC Mountainview’ (91%) was greater (P = 0.01) than ‘Nova’ sainfoin (62%). Further agronomic studies focusing on weed control in sainfoin stands and the optimum seeding ratios of sainfoin–alfalfa within the Parkland region of Saskatchewan are needed.