Flowering cover crops can suppress weeds while providing floral resources for beneficial insects

Incorporating cover crops into crop rotations is known to have many benefits to soil health and ultimately crop yield. However, they are often prevented from flowering--which would support pollinators--because of fear that the cover crops will set seed and later become weeds. A recent study published in the journal  Environmental Entomology shows that when some cover crops are allowed to flower, they not only provide important resources for pollinators, but they can also help suppress weeds in future crop rotations. The study compared floral resources, weed diversity, and economic weed abundance in crop fields across five cover-cropping treatments: one without cover crops (fallow), three with different combinations of flowering over crops, and one with non-flowering wheat. The flowering cover-crops provided the most food resources for pollinators, as expected. However, weed diversity was surprisingly highest in the field without cover crops. Weed diversity was lowest in the field with wheat as a cover crop, but wheat did not provide resources for pollinators. Weed diversity was measured at intermediate levels in the flowering cover-crop treatments, and interestingly, there were no differences in weeds of economic concern across the treatments. This indicates that allowing cover crops to flower and provide food for pollinators may not significantly impact crop yield in later rotations, creating a win-win situation for the farmer and biodiversity.


Banner Photo Credit: Julian Hanslmaier; unsplash.com