Should I pull up old Kale Plant or leave them

[Mamsoth]

This could be a stupid question but, last year I grew some Cavolo Nero which turned out wonderfully. This year they of course went to seed and all the leaves have shriveled and fallen off. This year I'm going to try some different kales in the raised bed. Should I completely pull the Cavolo up first or could I just cut the stem at soil level and leave the roots to decompose and enrich the soil and help the new Kales out a bit.

I know people say you shouldnt grow the same crops year after year in the same spot but this'll only be the second year and I really want to grow Kale again. : )

Thanks for any input

[ameno]

Pull them out. The stump is basically made of wood. It wont "enrich" the soil; it will just stay there taking ages to rot down.
I wouldn't even recommend putting the stumps on the compost bin, even cut up into pieces, as they just take too long to rot. I would only recommend composting them if you have a shredder you can feed them through.
The fleshier upper half of the stem is a different story, though. That rots quickly enough, so should be cut up and composted.

[Plot70]

I just put brassica stumps bake in the compost bin as a starter for the next batch.

[Mr Bones]

We twist them out so the smaller roots are left behind. The removed stems with stubby roots are then chopped up into about 1 inch sections with loppers and composted. If the woody root sections are cut lengthways as well it helps them break down quicker.
Re growing in the same place, ours are grown in a walk in cage, as soon as they're out peas go in then the peas are followed straight away again with kale. This is in beds that are compost mulched no-dig.