Humusica 2, article 13: Para humus systems and forms

Planet Earth is covered by very common Terrestrial (not submersed), Histic (peats) and Aqueous (tidal) humi- pedons. Beside these typical topsoils there are other more discrete humipedons, generated by the interaction of mineral matter with microorganisms, fungi and small plants (algae, lichens and mosses). In some cases roots and their symbionts can be a driving force of litter biotransformation, in other cases a large amount of decaying wood accommodates particular organisms which interfere and change the normal process of litter decomposition. Particular microorganisms inhabit submerged sediments or extreme environments and can generate specialised humipedons with grey-black or even astonishingly flashing colours. We describe all these common but still unknown humipedons, defining diagnostic horizons and proposing a first morpho-functional classification, which still has to be improved. At the end of the article, the hypothesis of evolving and interconnected Cosmo, Aero, Hydro, Humi, Co, Litho and Geopedons (related to the microbiota) is formulated as a speculative curiosity.