Inpedology,leaching is the removal of soluble materials from one zone in soil to another via water movement in theprofile.[1] It is a mechanism ofsoil formation distinct from the soil forming process ofeluviation, which is the loss of mineral and organiccolloids. Leached and eluviated materials tend to be lost fromtopsoil and deposited insubsoil. Asoil horizon accumulating leached and eluviated materials is referred to as a zone ofilluviation.
Laterite soil, which develops in regions with high temperature and heavy rainfall, is an example of this process in action.