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| Titel |
Development of biological soil crusts and their influence on soil hydrology in the recultivation area of lignite open-cast mining district in Lower Lusatia (Germany) |
| VerfasserIn |
R. Spröte, M. Veste, T. Fischer, T. Raab, O. Bens, R. F. Hüttl |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250064246
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| Zusammenfassung |
| Cyanobacteria, green algae, mosses and lichens are often the first colonizers of substrate and
initial soil surfaces. They are an important factor of initial soil formation as they stabilize the
substrate and decrease erosion processes. Biological soil crusts accumulate the initial soil
organic matter and provide nitrogen fixation. Once settled, the crusts influence the soil water
regime by delaying or limiting infiltration through enhanced water repellency. Aim of this
study was to compare the influence of biological soil crusts on soil hydrology under
conditions on various substrates and of different ages in recultivated areas of the open-cast
mining district of Lower Lusatia (Brandenburg, NE Germany) with various recultivation
aims.
In Brandenburg (NE Germany), where the climate is transitional between oceanic and
continental and the summers are characterized by generally low of precipitation (mean annual
rainfall 559 mm, mean annual temperature 9.3Ë C) open landscapes provide ideal conditions
for biological soil crusts, e. g. on mobile sand dunes in former military training areas and in
recultivation areas related to open-cast mining with initial soil development. Here biological
soil crusts are commonly found (Spröte et al., 2010). At five study sites in recultivation areas
with different reclamation approaches (natural development, pine reforestation, birch
reforestation) we defined four types of biological soil crusts: i) cyanobacterial and green
algae crusts on the soil surface with no vegetation where dominating sand grains were
physically stabilized in their contact zones by this crust type (type 1), ii) cyanobacteria and
green algae partially filled in the matrix pores and enmeshed sand grains between sparse
vegetation cover (type 2), iii) biological soil crusts with mosses which covered
most of the surface between the vegetation (type 3) and (iv) with soil lichens (type
4).
We investigated the development of the amount of chlorophyll a which is an indicator for
biomass productivity and depends from the species composition and crust type, and the water
repellency index which shows the influence of biological soil crusts on hydrological
parameters. Additionally, organic matter content (dry combustion) as well as soil pH (soil:
H2O = 1:2.5) were determined. Texture was analysed by wet sieving and fractionation pipette
method.
At all study sites and for all crust types soil pH ranged between 7.2 to 4.7 and decreased
from type 1 to type 4. Soil organic matter and chlorophyll a concentrations ranged from 0.3
and 1.7% and from 0.95 to 16.44 mg m-2, respectively, and increased from type 1 to type 4.
With few exceptions, water repellency indices ranging between 1.0 and 1.85, followed this
trend. Constrarily, infiltration rates decreased from type 1 to type 4. The cause for limited
infiltration is the swelling of extracellular polysaccharides in the biological soil
crusts (Fischer et al., 2010) and the influence of the particle size distribution and
porosity of the substrate with a relatively high content of silt and clay at some study
sites.
Fischer, T., Veste, M., Wiehe, W. & Lange, P. (2010): Water repellency and pore clogging
at early succesional stages of microbiotic crusts on inland dunes, Brandenburg, NE Germany.
– Catena, 80, 47-52.
Spröte, R.,Fischer, T., Veste, M., Raab, T., Wiehe, W., Lange, P., Bens, O., Hüttl, R.F.
(2010): Biological topsoil crusts at early successional stages on Quaternary substrates
dumped by mining in Brandenburg, NE Germany. Géomorphologie: relief, processus,
environnement 4/2010: 359-370. |
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