Humusica 1, article 7: Terrestrial humus systems and forms - Field practice and sampling problems

The present paper should be read after the six preceding articles dealing with fundamental concepts, vocabulary, principles and keys of our morpho-functional classification of humus systems and forms, the whole book being conceived as a guide for field studies. It now concerns seven questions which may arise when passing from knowledge to practice or, in other terms, from concepts to real things. In the field, humipedons can differ from reported photographs. Trees, bushes and/or herbs interfere with soil functioning and may generate different humipedons even over a relatively small surface. More generally a researcher must select a few unit plots re- presentative of a given natural floor for defining the frame of his investigation. In this article, authors present some practical and theoretical landmarks and illustrate some solutions for studying humipedons in common natural sites, and replacing them within ecosystem dynamics