8.02.03 – Humus and soil biodiversity

A network of European humus researchers was founded in Trento (Italy) in 2003, gathering 26 specialists from eight European countries. Since then, the group, meanwhile a Unit within the framework of IUFRO and joined by new participants, meets every year in different countries in order to exchange knowledge, discover humus forms in new ecological conditions and making progress in harmonizing humus classification concepts.

In 1992 and 1993 – almost simultaneously – two important humus form classifications were published: one in France (Brethes et al. – Référentiel Pédologique), developed from a long European tradition of research on humus (Kubiena, Duchaufour, Babel, Delecour, etc…); the other in Canada (British Columbia – Green et al.), re-examining the first approximation made by Klinka et al.
Since then, in Europe, several working groups tested these classifications (Fons et al., ...), trying – often – to compare these two methods (Calabrese et al. 1996, …).
However, neither of these proposals is fully applicable on a European scale, since both of them have been elaborated in a limited climatic context:

• The classification of Green et al. correspond to the climate conditions of the pacific North-West and is inadequate for active humus forms (MULLs);
• The French classification has some lacks in describing adequately the less active humus forms that are present in northern Europe.
• None of these two classifications is fully applicable to describe Mediterranean or mountain humus forms.

For this reason, it was thought important to gather some European experts, in order to:

• Pool knowledge and current projects on humus forms in different European regions (latitude, longitude, and variable altitude);
• list all issues that need further research to get an overall understanding of humus forms;
• get to an international research level, which would be useful to find further financing;
• suggest, a internationally accepted classification, on European scale, able to become a working group in World Reference Base of soils.

The European experts met in Italy (Trento 2003, San Vito 2005, Cagliari 2007), Austria (Vienna 2004, 2008), Germany (Freiburg, 2004), and France (Nancy 2006, Paris 2009). They published four important syntheses of their work.