Evaluation of an attempt to cultivate shrubs and trees on a heap of a potash mine

Starting at the end of November 1993, the Dr. Kahl GmbH has attempted to grow shrubs (Amorpha: Amorpha fructuosa and snow-berry: Symphoricarpos rivularis) and trees (poplar hybrid ‘University of Idaho’ Populus deltoides and Eleagnus angustifolia), on the heap of the potash mine Sondershausen/Harz (Free state of Thuringia). Patented water-saving planting method was used. A flexible planting container made of polyethylene was first filled with 50 g polyacrylamide (also called ‘hydrogel’) and after that with about 40 kg of a mixture of anhydrite (CaSO4) — the mean soil of the heap — and dried sewage sludge, respectively, composted sewage sludge on top of the hydrogel. After placing the container into the ground, one-year-old seedlings of the shrubs or trees were planted into the containers. Five years after planting investigations on the plants and soil were started. The results until now show that, using the planting method, Amorpha, the poplar ‘University of Idaho’ and the Eleagnus are able to grow under the poor conditions of the heap.