In the fall I sprinkled fall rye in all the garden beds but one. It grew beautifully over the winter. It was time to stir it in and that is when I discovered that fall rye and clay soil is not a good fit. You can't pull the rye out, you can't fork it out and the clay/thick clumps that came with the rye, do not break down. So using shovels and rakes, we ended up throwing most of the rye and clumps of thick soil into the compost bin. Then taking wheelbarrow loads of our precious horse manure and topping the beds up. So all in all it came out beautifully, but it was the work. The backbreaking work.
If I didn't garden in raised beds it would have been easy with a rototiller. So lesson learned. Do not plant fall rye in raised beds with thick dense soil.