Management of perennial forbs sown with or without self-regenerating annual clovers for forage and nectar sources in a low-input dryland production system

Forage systems can be designed to produce high quality feed for ruminant livestock while providing habitat for insect pollinators. We compared forage productivity, nutritive value, and selenium uptake as well as late summer nectar production of perennial forage species; alfalfa (Medicago sativa), birdsfoot trefoil (Lotus corniculatus), red clover (Trifolium pratense), sainfoin (Onobrychis viciifolia), and chicory (Cichorium intybus) as monocultures and intercropped with either subterranean clover (Trifolium subterraneum) or balansa clover (Trifolium michelianum) for two successive years in Oregon. Red clover intercropped with balansa clover out-performed other stands, producing over 11 t DM ha⁻¹ in 2019 and 9.4 t DM ha⁻¹ in 2020. Birdsfoot trefoil and sainfoin mixtures were dominated by subterranean clover, negatively affecting total forage yield and flower abundance. Chicory intercropped with subterranean clover formed a more balanced mixture with improved DM yield and nutritive value relative to chicory monocultures. Chicory was most responsive to Se-fertilisation in both years, having a higher concentration of Se relative to the other perennial species. Chicory also had high levels of condensed tannins (18.1–43.3 mg/g DM) relative to the other forages (1.8–17.5 mg/g DM). Red clover had the most consistent bloom in 2019, with 170 inflorescences per square meter at peak bloom and yielded an estimated total of 16.9 kg ha⁻¹ sucrose. Birdsfoot trefoil produced the most inflorescences during peak bloom in 2020 at 279 inflorescences per square meter. However, alfalfa had a higher estimated sucrose yield in 2020 at 241 kg ha⁻¹.