Tropical rain forests tend to have a lot of humus, but the soil in those biomes retain little of it because of leaching. what is leaching?

Natural process by which water soluble substances (such as calcium, fertilizers, pesticides) are washed out from soil or wastes. These leached out chemicals (called leachites) cause pollution of surface and sub-surface water.

Answertaurus is the highest in the sky;

How is this even a question?