The ‘dark earth’ revealing the Amazon’s secrets
by Zaria Gorvett on bbc.com, January 16, 2024
This layer of charcoal-black soil, which can be up to 3.8m (12.5ft) thick, is found in patches across the Amazon basin. It is intensely fertile – rich in decaying organic matter and nutrients essential for growing crops, such as nitrogen, potassium and phosphorus. But unlike the thin, sandy soils typical of the rainforest, this layer was not deposited naturally – it was the work of ancient humans. This rich soil is a relic from a very different time – an era when indigenous groups formed a thriving network of settlements across this rainforest world.