Effect of rockwool and lignite dust on physical state of rehabilitated post-mining soil

Abstract

Anthropogenic impact on the environment causes worldwide problems such as land degradation and increase in waste production. In particular opencast lignite mining results in various environmental disturbances and rehabilitation of this land is necessary. For this purpose some wastes: post-production rockwool and lignite dust can be used. Little is known about the influence of these amendments on physical state of reclaimed soil after opencast lignite mine. The aim of this study was therefore to assess the impact of post-production rockwool and lignite dust on physical properties of a post-mine Technosol considering at the same time the possibility of reuse of these waste materials. Soil samples came from 4 fields after a lignite mine: (1) control; (2) and (3) application of 200 or 400 m3 ha–1 post-production rockwool; (4) application of 1000 Mg ha–1 lignite dust. To achieve our objective we evaluated: gravitational water (GW), water available (AW) and unavailable (UW) for plants, air permeability (AP), saturated hydraulic conductivity (KS), soil water characteristic curves, unsaturated hydraulic conductivity function, pore-size distributions, texture, particle and bulk density, total porosity, TOC, pH, and soil structure. The application of post-production rockwool or lignite dust modified some physical parameters of the studied soil. The soil bulk density decreased to the largest extent resulting in the increase of the total porosity. The soil properties important for plant condition (AW, GW, KS and AP) were favourable. The study showed that the greenhouse post-production rockwool and the lignite dust can be utilized for the reclamation of post-mining soils, what will reduce at the same time their storage in landfills.