Healthy soil is the hidden ingredient

Humans can figure out a lot given enough time. While all the hype for us is finance, management, machines, electronics and software etc it is not unthinkable a previous civilization went all in on soil. Terra Preta seems to be quite sophisticated.

https://en.m.wikipedia.org/wiki/Terra_preta

South America was pretty advanced. The oldest evidence we have of widespread metallurgy comes from the tip of South America around approximately 5000 BC. Which predates metallurgy in Eurasia by thousands of years. Copper smelting was particularly important

https://en.wikipedia.org/wiki/Metallurgy_in_pre-Columbian_Am...

On the ecological side, some anthropologists argued that humans actually played a major role in transitioning Amazonia from mostly grasslands to the rainforest it is today around 10,000 years ago.

The distribution of many plant species is inexplicable without looking at human settlement patterns. So much so that other anthropologists have called the Amazon a "manufactured landscape".

https://sci-hub.ru/https://link.springer.com/chapter/10.1007...

>> Terra Preta - literally "black soil"

Terra Preta is noble savage fiction [1] created because charcoal stains the soil quite deep. (Similar to how the OP 'spotlight' is mostly fiction)

Biochar enthusiasts show the staining in soil cutouts after a few years.

I do a lot of biochar (100+ liters a week) but it has mixed results in the scientific journals, meta studies don't show a lot of improvement.

[1] The Amazonian cutting down of forests and burning it for quick release of nutrients works, but unless a third of your babies die you will run out of forest.

you can also say the Saharan desert played a major role on turning what Amazon is...

now, wow, calling it a grassland before humans 10,000 years ago is to smoke too much pot before reading/making papers. 5,000,000 AD then yes, maybe... /s but Terra Preta and other indigenous interferences is not even 10% of Amazon territory. various other animals are responsible for spreading diversity be it by shitting seed or just moking stuff around to make nests or impress some partner. the rainforest are also there because mountains changing courses of rivers.

[0] "Geology and geodiversity of the Amazon: Three billion years of history" https://www.theamazonwewant.org/wp-content/uploads/2022/05/C...

[1] the grassland hypothesis (somewhere in the text) and other curiosities about its biodiversity https://www.science.org/content/article/feature-how-amazon-b...

There is a lot of research showing that terra preta works and that Amazonion tribes create it.

Biochar is just the first step in making Terra preta so it's not a surprise that it doesn't work as well as the final product.

> The oldest evidence we have of widespread metallurgy comes from the tip of South America around approximately 5000 BC. Which predates metallurgy in Eurasia by thousands of years.

There are archaeological finds in Europe dating smelting in the region back as early as 5500 BC.

https://en.wikipedia.org/wiki/Pločnik_(archaeological_site)

This is common knowledge. Even the Wikipedia page states:

> There is evidence that there have been significant changes in the Amazon rainforest vegetation over the last 21,000 years through the last glacial maximum (LGM) and subsequent deglaciation.

https://en.wikipedia.org/wiki/Amazon_rainforest

Also, there's this:

https://www.discovermagazine.com/planet-earth/10-800-years-a...

the Wiki citation doesn't even have a source, nor is calling that indigenous people made it

your last link is about Llanos de Moxos, which isn't in Amazon. you don't seen to understand even basic geography... even if Llanos was 100% man-made (and isn't) and it was part of the Amazon (and not a region that borders it) it would be the equivalent of 2.6% of the whole Amazon area. concluding such a thing because 3% of an area that benefited (soil quality wise) from billions of years of geologic events and was partly modified by humans is ignorant but again, Llanos isn't even Amazon

it was common knowledge among middle age that Earth was flat. doesn't seem an argument to me

There were elephants there that humans hunted to extinction, elephants typically keep forests down and create grasslands. So it seems likely it happened, and that humans was the cause (by killing the elephants).

Edit: So it is likely that the change happened and had nothing to do with the soil change.

Have we not gone all in on soil? Your CPU and GPU comes from the soil. The electrical batteries powering all your electronic device comes from the soil. Take a hard look around you, almost everything "artificial" you can see and touch came from the ground.

Lots of things come from the earth for sure, but I think soil is worth distinguishing from the sources of silicon wafers and lithium batteries.

Soil is a living, breathing, hospitable community of earth, fungi, insects, water, and countless other organisms. You can’t make silicon wafers from it, but it’s the cornerstone of entire ecosystems. It might be one of the most precious yet overlooked natural resources

I never said Amazonian grasslands was manmade. Reread your own comment to understand the context

The Wikipedia source was to back up the claim that Amazonia was largely grasslands about 10-20k years ago. That is what is common knowledge.

Yes but I said "widespread" metallurgy. There are evidence of metallurgy that is even older than 5000 BC in South America but it's not widespread enough for me to point it out. We even have evidence of copper processing 10,000BC in the Near East but I also didn't think that was worth pointing out

https://www.sciencedaily.com/releases/2017/09/170901113607.h...

why are almost all your comments "dead"? weird

>it was common knowledge among middle age that Earth was flat. doesn't seem an argument to me

And you don't seem to know basic history, casting doubt on other things you say. Nobody serious in the middle ages (or since much further back than that either) thought seriously that the Earth was flat.

actually i meant "geocentrism" but it was too late to edit but you are right, middle age didn't thought Earth was flat

now if you are defending this absurd commentary that Amazonia was a grassland 10,000 years ago and turned out to be what's because humans, i think you both are on the level of flat earth 21° century people

No, not defending that, since evidence points to it having been a forest, but that a place like the Amazon could form from grassland in the span of a few thousand years is absolutely possible.

the western part once turned into a huge wetland, after the Andes emerged from the ocean. that was more than 10 Ma ago although. that was also what made the western Amazonia part differ on its biodivesity

humans may altered the biodiversity of Amazonia by breeding only wanted species. but we don't have too much evidence of that (yet). but if it was, the biodiversity of pre-humans was probably richer, as indigenous apparently managed the forests with fire and farmed hyperdominant cultures [0]

[0] https://portal.amelica.org/ameli/journal/181/1813954027/html...

Depends, there’s elephants in the Congo forest, they’re just not too easy to see.

The trees grow faster than the elephants can wreck them. But in areas with less rain fall elephants keep the grasslands more open.

As did Mammoths in the northern forests.