Maybe humans didn't create terra preta soil fertility

A new study suggests that maybe human involvement had nothing to do with the creation of Amazonian Dark Earth (ADE) formation.  Pretty fascinating read suggesting that people in the Amazon may have taken advantage of the ADE soils without having actually created them.  Nature.com study article

From the article:  "The current view of ADE genesis suggests that the artefacts found in nutrient- and charcoal-rich Pretic horizons result from biomass burning and application to the soil. This view has fuelled an entire industry of charcoal production from biomass (i.e. biochar) in which ADEs are described as a model for sustainable agriculture20. Under experimental application, however, biochar alone (or in combination with fertilisers) has proved inadequate to replicate basic characteristics of indigenous ADEs, such as their long-lasting mineral fertility21,22,23. This reveals a lack of understanding that warrants further investigation into the genesis of ADEs."

"This hypothesis implies that pre-Columbian societies understood and exploited natural processes of landscape formation, which led to the unique properties of ADEs, but were not responsible for their genesis. Our findings do not preclude, however, a more recent human effect on the local environment. The wisdom of native populations, manifested for example in the well-documented recent application of waste materials to the soil, may well have further enriched ADE profiles or, at least, countered their otherwise-inevitable degradation."

I'm certain that more and more will be discovered about this topic in the future, and hopefully, aid us in re-creating these incredibly fertile soils.

Interesting! But I don't think a natural fire regime plus deposition fully explains it either, though. Terra preta occurs in concentrated sites and the unaltered soil in the same locality has almost no pyrogenic carbon to speak of. I think it's very possible that the people living there observed enhanced plant growth in these unusual spots and instead of using that knowledge to adopt slash and burn agriculture like in so many other places around the world, they chose to continuously modify soils in a more permanent fashion. The jury is still out on how early the first humans arrived in that neck of the woods, too. 20,000 years is not completely out of the question if the Malpais model is valid...but the scale of alteration is a little hard to imagine being the work of the first wave of settlers.

At this point I guess the whole thing is academic, because the relevance to us is more about what we can do with biochar in the present day.

This is an interesting hypothesis, but not yet a theory.  It is not yet substantiated by a coherent trail of facts.  I guess to me it doesn't matter too much if they discovered this effect, then tried to mimic it in their fields.  We are, after all, trying to mimic what they did.  Perhaps this line of investigation will help us find out more about its origins, and how to make it more effectively.  Cool idea.
John S
PDX OR

With that title, I was hoping "aliens" ;)

M

A follow up -
https://news.mit.edu/2023/ancient-amazonians-intentionally-created-fertile-dark-earth-0920