R. Wilden et al., Soil solution chemistry of two reclamation sites in the Lusatian lignite mining district as influenced by organic matter application, PLANT SOIL, 213(1-2), 1999, pp. 231-240
Due to a large reclamation (recultivation) demand in the Lusatian lignite m
ining district, efficient strategies for the rehabilitation of abandoned mi
ne sites are needed. A field study was conducted for comparing the effects
of three different fertilizer treatments (mineral fertilizer, sewage sludge
and compost) on soil solution chemistry of both a lignite and pyrite conta
ining spoil as well as a lignite and pyrite free spoil. The lignite and pyr
ite containing spoil was ameliorated with fly ash from a lignite power plan
t (17-21 t ha(-1) CaO), whereas the lignite and pyrite free site received 7
.5 t ha(-1) CaO in form of limestone. Fertilizer application rates were: mi
neral fertilizer 120 N, 100 P and 80 K kg ha(-1). 19 t ha(-1) sewage sludge
and 22 t ha(-1) compost were applied. Soil solution was sampled in 20, 60
and 130 cm depth for the period of 16 months. Solution was collected every
fortnight and analysed for pH, EC, Ca2+, Mg2+, K+, Na+, Fen+, Aln+, Mn2+, Z
n2+, NO3-, NH4+, SO42-, Cl-, PO43-, C-inorg and DOC. Lignite and pyrite con
taining spoil differed clearly from lignite and pyrite free spoil regarding
soil solution concentrations and composition. Acidity (H+) produced by pyr
ite oxidation led to an enhanced weathering of minerals and, therefore, to
at least 10 fold higher soil solution concentrations compared to the lignit
e and pyrite free site. Major ions in solution of the lignite and pyrite co
ntaining site were Ca2+, Mg2+, Fen+, Aln+ and SO42-, whereas soil solution
at the lignite and pyrite free site was dominated by Ca2+, Mg2+ and SO42-.
At both sites application of mineral fertilizer led to an immediate but sho
rt term (about 1 month) increase of NO3-, NH4+ and K+ concentrations in soi
l solution down to a depth of 130 cm. Application of sewage sludge caused a
long term (about 16 months) increase of NO3- in the topsoil, whereas NO3-
concentrations in the subsoil were significantly lower compared to the mine
ral fertilizer plot. Compost application resulted in a strong long-term inc
rease of K+ in soil solution, whereas NO3- concentrations did not increase.
Concentrations of PO43- in soil solution depend on solution pH and were no
t correlated with any treatment.