Roller-crimping an overwintered cover crop is an sound alternative to herbicide termination. In this video, Scott Shriver explains how roller crimping works on his Jefferson, IA organic farm. Roller-crimping should occur at anthesis or pollen-shed of the rye.
For plenty of biomass and better weed suppression, Scott typically drills two to three bushels/acre of cereal rye in the fall. He has had success with ND Gardner rye, which accumulates a lot of biomass before roll-down. Scott has also been recommended Danko rye, which has early anthesis and rolls-down effectively.