Temporal and spatial development of soil solution chemistry and element budgets in different mine soils of the Lusatian lignite mining area |
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Authors: | Schaaf W Gast M Wilden R Scherzer J Blechschmidt R Hüttl R F |
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Abstract: | Lignite and pyrite contents in the dump materials of the Lusatian opencast mining district in East Germany result in high
acidification and salinization potentials. These extreme conditions require considerable amounts of alkaline materials like
ash or lime to enable recultivation and revegetation. Investigations at chronosequence sites on different mining substrates
show characteristic developments of the soil solution chemistry. Processes like weathering of primary and formation of secondary
mineral phases, acid production and buffering, and their impacts on both the solid and the liquid soil phase result in high
temporal and spatial dynamics especially in the initial phase of soil and ecosystem development. To study these processes
we continuously collected soil solutions from different soil depths at seven sites with two representative soil substrates.
All sites were afforested with pine and cover stand ages from 1 to 60 yr. The results show that actual pyrite oxidation occurs
at the youngest sites on lignite and pyrite containing substrates leading to extremely low pH values and high Fen+ and SO4
2- concentrations. The considerable acid production causes weathering of aluminium silicates resulting in high Aln+ concentrations. Ca2+ concentrations are unexpectedly high even at low pH showing no correlation to amelioration amounts or depths. Therefore it
seems most probable that these mining substrates contain geogenic Ca sources. The transport of dissolved weathering products
is limited due to low leaching rates enabling formation of secondary phases which control the actual composition of the soil
solution. Depth gradients of the soil solution composition at the chronosequence sites point to a gradual transport and leaching
of these secondary phases from the soil profiles. Soil solution composition and dynamics at lignite and pyrite free sites
show completely different patterns and have a higher potential for successful sustainable recultivation.
This revised version was published online in June 2006 with corrections to the Cover Date.
This revised version was published online in June 2006 with corrections to the Cover Date.
This revised version was published online in June 2006 with corrections to the Cover Date. |
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Keywords: | Ash application mineral formation mineral weathering Pinus nigra (Arnold) Pinus sylvestris (L ) pyrite |
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