Abstract
Bulk density, porosity, water holding capacity, water field capacity, wilting point, clay content, hydraulic conductivity, and soil moisture were studied in unreclaimed sites (5, 15, and 25 years old) and reclaimed sites (20-30 years old) on a post-mining spoil heap near Sokolov, Czech Republic. The unreclaimed sites had been spontaneously colonized by shrubs, and the reclaimed sites had been planted with pine, spruce, oak, alder, or meadow (the meadows were created by the spreading of topsoil and grass seed).
Soil bulk density decreased with site age and was similar in unreclaimed and reclaimed sites except in the meadow sites, where bulk density was highest. Field capacity (in terms of volumetric soil water content) increased with site age and was similar in unreclaimed and reclaimed sites except for the meadow sites, which had the lowest field capacity.
The wilting point (in terms of volumetric soil water content) decreased with age in unreclaimed sites, was higher in reclaimed sites than in unreclaimed sites, and was higher for the meadows than for other sites. Hydraulic conductivity was generally low but was highest in young sites.
Soil moisture content had no clear seasonal pattern in young, unreclaimed sites (which had little vegetation), but decreased in summer in all vegetated sites. Soil moisture was highest in the reclaimed alder sites and was lowest in the reclaimed pine and meadow sites.
Relative to unreclaimed sites, reclaimed sites had a higher ability to hold water but a higher wilting point, such that water availability for plants was similar in both kinds of sites. The water deficit was highest in the reclaimed oak sites followed by the meadow sites.
The latter finding indicates that the spreading of topsoil during reclamation does not result in improved soil moisture conditions 20 years later.