It takes only a few hours for most nutrients from dead plants or animals to be taken up by bacteria and other tiny organisms. Some of those are eaten, so their nutrients go to animals. Others convert nutrients and carry them to plant roots. Chains of living organisms pass nutrients on, like firemen buckets of water. This keeps rain forests healthy in such poor environments.
Tropical people get their food from such soils.
Since long, they understood recycling. Tropical ways to practice agriculture were sustained during thousands of years, for example in Mexico, Indonesia or Ethiopia. Tropical rain forests produce food for no more than two or three people per square kilometre. Forests can only keep human groups alive if converted, partly into crop fields and partly into village forest gardens. Till this day, successful tropical agricultural cycles imitate the recycling and biological diversity of the original forests.