There's a lot of weenies on youtube that just use coarse wood chips (with leaves/needles) and just keep adding to them every couple of years. They keep breaking down and enriching the soil while the top layer mulches and inhibits weeds. My chicken run is on its 4th year with wood chips and when I dig down I can see the white stranded mycorrhizae in the broken down fertile soil. That's probably why the bamboo goes so insane in there...a little chicken poop here and there probably helps too.
I used a horticultural blend mulch (natural mulch + compost) last year in my garden beds, but never actually planted. It all broke down over winter so I'll plant in it this year and add more of the mulch on top. It'll probably go nuts this year.
When you think about it the forest is super fertile and needs no additives. It's just a self sustaining system (as long as we don't mess it up). All you have to do is sorta mimic the forest and let the soil and microorganisms do all of the work on their own.