Humus index: An integrated tool for the assessment of forest floor and topsoil properties

A quantitative assessment of forest humus forms is suggested, on the basis of a scale ranging from 1 (Eumull) to 7 (Dysmoder) which is called the humus index. Regression analyses showed that this index was well-correlated with several morphological as well as chemical variables describing forest floors and topsoil profiles: thickness of the Oe horizon, depth of the crumby mineral horizon, Munsell hue, pH(KCl) and pH(H2O), H and Al exchangeable acidity, percentage base saturation, cation-exchange capacity, exchangeable bases, C and N content and available P of the A horizon. The suggested humus index could be used as a cheap and rapid method for the bulk assessment of organic matter accumulation, soil-acidity, and soil biological activity.