Forgive me for reviving a year old thread, but While I can create the worldconfig, it doesn't seem to work after I've made it and I'm unable to edit afterwards unless I completely redo the /worldconfigcreate command.
Doing /worldconfig cropGrothRateMul will read out the set value, but if I try to change it, it simply reads out "No such config found: cropGrowthRateMul" and seems to not work at all when reloading the world. I can't find anywhere if this still even works hence why I'm throwing my hands up and reviving this thread in desperation since it's one of the only ones I can even find on it.