Using pennycress, camelina, and canola cash cover crops to provision pollinators

Abstract

As pollinator decline continues, the need to provide high value forage for insects increases. Finding agricultural crops to diversify the landscape and provide forage is one way to improve pollinator health. Three winter industrial oilseed crops (pennycress, winter camelina, and winter canola) were grown in Morris, Minnesota, and Brookings, South Dakota, during the winters of 2012–2013 and 2013–2014. Each of the three crops has pollinator-friendly flowers and value as winter cover crops and cash seed crops. The crops were evaluated for pollinator use, nectar production, green cover, and yield. Pennycress, camelina, and canola flowers had high insect activity with maximum visitation rates of 67±11.5, 22±3.1, and 61±6.8 insects min−1. Cumulative nectar produced by pennycress, camelina, and canola was 13, 100, and 82kg of sugar ha−1 during the 2014 anthesis period, providing an important food resource to pollinators during early spring when there is little else on the agricultural landscape that is blooming. Green cover in early spring ranged from 0 to 60% amongst the three crops, with camelina providing >25% green cover across all four site-years. Maximum seed yields were 1.1±0.04, 1.4±0.05, and 1.2±0.19Mgha−1 for pennycress, camelina, and canola, respectively, which are economically viable harvests. Of the three crops, winter camelina provided the highest combined agroecosystem value through pollinator resources, green cover, and seed yields.