Soil fauna of a reclaimed lignite open-cast mine of the Rhineland: improvement of soil quality by surface pattern

Reclaimed lignite open-cast mine areas in the Rhineland are covered by a mi xture of loess and sand deposits containing organic material that originate s from the upper quartary soil which has been taken from the front of the m ining path. Consequently, the soil fauna that has established itself on the reclaimed open-cast mine areas may result from the primary succession and also from species that are carried to the dumping mines and are able to sur vive the dumping process. The reclaimed landscape consists of a regular str uctural pattern of crests and troughs. The troughs provide appropriate habi tats for establishing a rich and diverse fauna with higher densities of alm ost all animal groups investigated, with enhanced microbial activity and hi gher values of available macronutrients. In terms of plant growth, the phys ical and chemical conditions found in the troughs exceeded the conditions f ound on the crests. From laboratory studies we made the following conclusio ns: (1) environmental conditions in the troughs were improved not only by e rosion, but additionally by the soil fauna that directly enhanced microbial activity and indirectly increased the availability of macronutrients; (2) soil animals improved soil quality by increasing the pH-values, increasing the ammonium-nitrogen content and decreasing the contend of aluminium ions; and (3) a multiple-species system is able to improve soil quality more eff ectively than a single-species system. (C) 2001 Elsevier Science B.V. All r ights reserved.