Significant yield benefits from honeybee pollination of faba bean (Vicia faba) assessed at field scale

There is growing evidence globally that improved pollination practices can help support higher yield and reduced variability for a wide range of insect pollinated crops. Managed honeybees are provided to pollinate some orchard crops, but they are less commonly used for field crops, in part because of uncertainty as to whether the potential benefits are justified by the costs. This uncertainty comes from a lack of studies conducted at the appropriate scale. In this study we examine the yield benefits from managed honeybees applied to Vicia faba in field scale trials. We provided honeybee hives to 17 fields in South Australia, and observed that bee activity and fruits per stem decreased with increasing distance from hives. We examined the spatial pattern of yield using yield map data collected at harvest and found there was an effect of distance from hives on mean yield (declining with distance) and spatial variability of yield (increasing with distance). The presence of a distance gradient was consistent across all fields, across two years, two V. faba varieties and two different bee-hive management methods. The average benefit is estimated to be an additional 17% yield, 90% of which is attained within 767 m of hives. Our economic analysis indicates that provision of hives is profitable for a wide range of realistic values for crop value (dollars per tonne) and pollination cost (dollars per hive).