Long-term weed dynamics and crop yields under diverse crop rotations in organic and conventional cropping systems in the Canadian prairies

•Long-term impacts of organic and conventional rotations on weed dynamics were studied.•Reduced inputs in conventional systems did not affect weed abundance or yields.•Organic systems had high weed abundance and low crop yields.•High diversity rotations did not provide benefits in weed management or in increasing yields.•All systems showed an increase in yields despite an increase in weed abundance.