Pollinators and other beneficial insects within two brassicaceous oilseeds and a cover crop mix under evaluation as fallow surrogates for dryland production systems of the northern Great Plains

Authors: Campbell, Joshua; Rand, Tatyana; Allen, Brett; Jabro, Jalal - Jay; Rana Dangi, Sadikshya; West, Natalie; Morphew, Alexandra

Submitted to: Journal of Kansas Entomological Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2023
Publication Date: 4/9/2024
Citation: Campbell, J.W., Rand, T.A., Allen, B.L., Jabro, J.D., Rana Dangi, S., West, N.M., Morphew, A.R. 2024. Pollinators and other beneficial insects within two brassicaceous oilseeds and a cover crop mix under evaluation as fallow surrogates for dryland production systems of the northern Great Plains. Journal of Kansas Entomological Society. 96(3):78-92. https://doi.org/10.2317/0022-8567-96.3.78.
DOI: https://doi.org/10.2317/0022-8567-96.3.78

Interpretive Summary: Growing wheat is usually done in alternating years with fallow (random grasses and other weedy plants) allowed to grow in between years. Some farmers are attempting to grow an economically valuable crop instead of fallow. Oilseed and various cover crops are being explored. Due to native pollinator declines, we sweep netted for bees and other pollinators off two oilseed plants and a cover crop mix that can be grown successfully in the Northern Great Plains. We found that all three fallow replacement crops attract a diverse pollinator community. Thus, growing oil seed plants or a cover crop mix may provide pollinating insects with valuable nectar and pollen that fallow may not provide.

Technical Abstract: Dryland wheat farming commonly uses a rotation of wheat to fallow between years but growers have begun to diversify crop rotations for a variety of environmental and economic reasons. Ethiopian mustard (Brassica carinata A.) and camelina (Camelina sativa L.), two oil seed crops, can be successfully grown in the Northern Great Plains (NGP) and could be a suitable fallow replacement. Native bees have declined in abundance and richness primarily due to conversion of natural habitat to row crops and honey bees have become increasingly difficult to manage in recent years. Thus, it is important to determine how flower visiting insects utilize novel crops. We collected flower visiting insects via weekly sweep netting events during two growing seasons to determine abundance and richness of bees and other insect pollinators on B. carinata, C. sativa, and a ten species cover crop. Overall, numerous native bees and other flower visiting insects were collected off all three potential fallow replacements. These crops may provide important floral resources for bees and other pollinators and could be used to improve pollinator resources within cropping systems of the NGP.