Oxisols
Oxisol soil is low in nutrient minerals and exists in tropical and subtropical areas with ample precipitation. Little organic nutrients accumulate on the forest floor because the leaves and twigs are rapidly decomposed. The A-horizon has lots of humus from the decayed litter. The B-horizon is quite thick but is highly leached and nutrient poor. Although rainforests appear to be very fertile, all of the nutrients are locked up in the vegetation rather than the soil. As soon as plants or animals die and begin to decay, the nutrients are rapidly absorbed by plants.