Humusica 1, article 3: Essential bases ‒ Quick look at the classification

International audience; Terms and concepts have been defined in Humusica 1, article 1 and the functioning of humus systems has been discussed in Humusica 1, article 2. Here a short overview of the matter, showing humus systems in their environment, is provided for beginners, before making field investigations. The present work is intended as a part of the field manual (Humusica 1 and 2), an illustrated, easy-to-use application tool for humus systems classification, helpful even for not (yet) expert pedologists. The present article gives also a fast look at the classification, sharing Terrestrial, Histic, Aqueous and Para humus systems, every group being defined by its characteristics set in synthetic tables, and suggests a step-by-step approach allowing everyone to classify and investigate humus systems and forms.