Not sure why you're being condescending when you're totally uninformed & wrong lol.
> The fertile soil is a result of a long process of bringing organic material and ash and depositing it on the field. Exactly the opposite of what we are doing today
2 minutes of research would tell you that the Terra Preta soil consists of - tiny, broken pottery shards - weathered charcoal - bones/compost/manure
> It is very easy to see how this developed. They probably have noticed that if they keep throwing their leftovers or feces in a particular area, everything starts growing better there. The same if you throw out ash. Which they had lots of beacuse they were burning a lot of wood every day, living in the rainforest and not facing energy price hikes. If you have a village and you hunt and gather every day, if you constantly keep burning wood fire and spread it all around your village for thousands of years -- guess what -- whether you planned it or not you will create those fields because I bet nobody would be trucking the garbage far from the village.
The fact that you keep referring to them as hunter-gatherers when they've clearly developed an advanced fertilizer is hilariously absurd.
They were clearly advanced at farming.