Quelle: European Atlas of Soil Biodiversity
Three different humus forms, known as Mull, Moder and Mor
can be viewed as the outcome of three different
“strategies” of terrestrial ecosystems.
• Mull is characterised by an intense mixing of organic matter with
mineral matter (i.e. as the result of earthworm activity). This
results in a crumbly and nutrient-rich organo-mineral horizon.
• Moder is characterised by a less rapid transformation of
litter by litter-dwelling animals and fungi, resulting in the
accumulation of organic humus at or near the soil surface.
• Mor is characterised by the slow transformation and
accumulation of undecayed plant debris, with a sharp, clearly
defined transition from the humus to the mineral soil.