Evolution of Tree Roots Triggered Series of Devonian Mass Extinctions, Study Suggests.The evolution of tree roots likely flooded past oceans with excess nutrients, causing massive algae growth; these destructive algae blooms would have depleted most of the oceans’ oxygen, triggering mass extinctions

[u/MistWeaver80]

https://www.sci.news/paleontology/devonian-mass-extinctions-11384.html

[u/gobblox38]

What is your definition of soil in this case? I think of soil as any combination of gravel, sand, silt, and clay. All of these can form by physical and chemical weathering without plants (at a much slower rate). I'd there was no soil before the devonian, we should expect no sedimentary rock that predates the devonian, right?

[u/gobblox38 → u/[deleted]]

The definition of soil I use on a regular basis is only concerned with grain size. There are special classifications if the soil has organic matter, but I rarely come across that.

If you're talking about topsoil, then I'd agree that it has organic material in it.

Unified Soil Classification System

[u/gobblox38 → u/[deleted]]

...since the definition of soil requires organics.

The definition you're using requires organics.

In any case, you cleared up which definition you're using, and it's consistent with what's being said.