Intercropping industrial hemp with cowpea increases productivity of pollinator dependent-crops

Industrial hemp (Cannabis sativa) has recently gained importance because it is a multipurpose crop that can be grown for fiber, grain, and cannabidiol (CBD). Hemp produces large amounts of pollen which may probably have an ecological value to pollinators in cropping systems. Field research was conducted to determine if intercropping industrial hemp (Joey [IH]), cowpea (Pinkeye Purple Hull [PPH]), and squash (SQ) [yellow Tempest] in a polyculture system would increase pollinator abundance and crop yield. Experiments were set up in a RCBD with five treatments (IH-PPH, SQ-PPH, PPH-SQ, and IH-SQ), and the control plots (without intercropping) were planted ~9 m from the intercropped plots. Planting dates were staggered to synchronize flowering. Data was collected from direct visual counts, pan traps, and vacuum sampling. A total of 2,767 pollinators (bumble bees, carpenter bees, honeybees, sweat bees, and wasps) were recorded. The abundance of pollinators in all intercropped treatments (1717) was greater than the control (504). Pollinator abundance was higher on the intercropped treatments as follows CP-SQ (153) >IH-SQ (81.25) >IH-CP (72) and lowest on the controls. Industrial hemp and cowpea intercrop treatments recorded more pollinators than controls. Squash intercropped with cowpea, and industrial hemp had a higher yield than the control. Our results indicate that cowpea and industrial hemp attracts pollinators which benefitted squash. Therefore, intercropping industrial hemp and cowpea with crops dependent on pollinators may be an effective way to attract pollinators into the cropping system for increased crop production.