There is an old garden bed at the house I just moved into, and it’s covered with clover. If I pull out the clover, what are the chances that it has distributed any nitrogen into the soil? Does the clover have to be dead for it to release the nitrogen bulbs at the end of its roots? How would clover go about dying? I am very uncertain and very interested in learning more about this stage of nitrogen fixation!
I assume that you have a garden of White Clover that has taken over.
Here is a link that will help you with the removal.
This link will help you understand the process of White Clover as a cover crop.