Cover crop effects on maize drought stress and yield

•Grew maize in ambient and drought conditions after functionally diverse cover crops.•Organic system with full inversion tillage; only 1 or 2 preceding cover crops.•Cover crops neither ameliorated nor exacerbated drought stress in the following maize.•Cereal rye reduced maize yield relative to cover crop treatments that contained legumes.•New hypothesis: drought might limit nitrogen supply when relying on organic N sources.