Workshop and exkursion: 13. - 15.09.2019: Initial Humus forms in reclaimed soils of the open cast brown coal mines in Lower Lusatia

By AG Humusformen of the German Soil Science Society and Research Institute for Post-Mining Landscapes

Recultivation of post-mining areas by afforestation leads to the development of soils with significant increase in soil organic matter. The accumulation of soil organic matter in and on the mineral soil is one of the first pedogenic processes in theses soils. In accordance to the predominant soil forming factor an A-layer and different humus form will develop.

On the young soils of the post-mining brown coal area of Lower-Lusatia a time sequence of different humus forms can be observed, proving the dynamic of humus layer in forest soils. 20 years after recultivation only initial humus forms have developed under pine. 50 years after recultivation mull like moder and a typical moder with little finehumus can be observed under sessile oak and pine, respectively. At sites recultivated 80 years ago, a mor like moder have developed under pine trees. These humus forms are comparable to the humus forms which can be observed at undisturbed sites  on fluvio-glacial sands and equivalent vegetation.

Besides the age of the soils, the effect of the forest management, the vegetation and stand development as well as the substrate type on humus form are evident. The influence of base rich dust and ashes originating from the coal processing industry on the humus form can be evaluated with decreasing distance to the factories. Up to date, humus forms developing in ashes of the coal processing industry are not described.

Workshop Humus Forms - Working Group Humusforms

Hardehausen, Ostwestfalen, 6.-8. Juli 2018

The procedure of the description of the humus form varies according to the targeted objective. A form sheet used for the description of humus forms within the National Forest Soils Inventory and a new developed identification key for humus forms were both tested. The form sheet enables a very detailed description of the humus form, with data fields useful scientific information which are not entirely necessary for the deduction of the humus form. The complete description is more time-consuming. The survey with the identification key results in the same humus forms within a shorter time. Testing both procedures indicated, that some changes of the identification key are necessary to improve the accurancy of the outcome.

A general survey of the German stratification of humus forms is downloadable.