Cover crops provide multifunctional benefits for agroecosystems. In addition to protecting soil between cash crop plantings, cover crops can also feed livestock and supply valuable forage for pollinators. Here we evaluated three flowering cover crops for their potential to provision floral resources for pollinators while providing nutritive forage for ruminant livestock. We assessed winter camelina, a cool season crop planted in the fall and harvested the following spring, as well as buckwheat and sunflower, both warm season crops planted and harvested within the same growing season. For each cover crop, we measured flowering, insect visitation, visitor types, and forage yield. We also modeled potential energy provided to dairy and beef cattle and predicted milk yield of lactating dairy cows fed diets incorporating each crop. We found that winter camelina flowered and had the most insect visitation in mid-spring, buckwheat reached peak flowering and visitation mid-summer, and sunflower achieved peak flowering and visitation in late summer. Cover crops attracted mostly non-bee visitors followed by small and large dark bees. When added to modeled diets, all three crops provided enough energy for growth in dairy cows but only buckwheat and sunflower increased caloric gains for beef cattle. While diets with buckwheat or sunflower provided enough energy for milk production in lactating cows, diets with camelina were inadequate for milk production. Our findings demonstrate that flowering cover crops can provide forage resources for pollinating insects and supply cattle with adequate energy for growth and milk production when incorporated into traditional diets. • Cover crops may provide multifunctional ecosystem services in agricultural systems. • Flowering cover crops can supply forage for pollinators and feed for livestock. • Cover crops may fill gaps in spring and summer resources for various pollinators. • Harvested cover crops may increase caloric intake in dairy and beef cattle diets. • Cover crop forage value varies with crop phenology and agroecosystem context.
Gambel et al. (Wed,) studied this question.