A proposal for including humus forms in the World Reference Base for Soil Resources (WRB-FAO)

Abstract

The morpho-functional classification of humus forms proposed in a previous issue by Zanella and collaborators for Europe has been extended and modified, without any change in diagnostic horizons, in order to embrace a wide array of humus forms at worldwide level and to complete and make more effective the World Reference Base for Soil Resources. For that purpose 31 Humus Form Reference Groups (HFRGs) and a set of prefix and suffix qualifiers are proposed, following the rules erected for the WRB. An exhaustive classification key, respecting the principles of WRB, is suggested and examples of classification are given for some already well known humus forms

Humusica 2, article 10: Histic humus systems and forms – Key of classification

“…Humusica recovers keys of classification published in preceding works (Jabiol et al, 2013;Zanella et al, 2011Zanella et al, , 2009). Here, we have introduced important improvements at the level of vocabulary, précising terms and diagnostic horizons.…”

Humusica 1, article 2: Essential bases—Functional considerations

“…Observing the topsoil of different terrestrial ecosystems in Europe, five main humus systems have been pointed out and called Mull, Moder, Mor, Amphi, and Tangel (Zanella et al, 2011a, b;Jabiol et al, 2013). A key of classification, based on characters of diagnostic horizons, allows us to identify humus systems in the field.…”

The impact of parent material, climate, soil type and vegetation on Venetian forest humus forms: A direct gradient approach

“…The aim was to assess whether the influence of (i) components of climate (temperature, precipitation), elevation, aspect, soil type and substrate (carbonated versus silicated parent materials), known to affect forest humus forms in other North Italian contexts (Carletti et al, 2009;Bonifacio et al, 2011;Ascher et al, 2012), and (ii) vegetation, whose effects have been well-established at a very local level (Schulp et al, 2008;Trap et al, 2011Trap et al, , 2013, could be retrieved in the regional context of Veneto. For that purpose we used for the first time a new classification of humus forms, based on morpho-functional principles previously defined at European level by Zanella et al (2011), then refined by Jabiol et al (2013) …”