Humusica 1, article 4 : Terrestrial humus systems and forms-Specific terms and diagnostic horizons

Knowledge of a little number of specific terms is necessary to investigate and describe humipedons. This “new vocabulary” allows individuating and circumscribing particular diagnostic horizons, which are the fundamental bricks of the humipedon. Few “components” defined by specific terms characterize a specific “humipedon horizon”; few “humipedon horizons” compose a given “ humusform” and some similar “ humusforms” are grouped in a functional “ humussystem”. In this article, specific terms and humus horizonsare listed and explained one by one. Field difficulties are illustrated and resolved. The aim of the article is to present in a manner as simple as possible how to distinguish in the field the soil structuresallowing a morpho-functional classification of terrestrial (aerated, not submerged) humipedons.