Abstract form

Vegetation induced patterns of soil redox conditions and dissolved iron
Zoltán SZALAI* 1,2 , Gergely JAKAB 2 , Klaudia KISS 1 , Katalin FEHÉR 1
1 Department of Environmental and Landscape Geography, Eötvös Loránd University,
Budapest, Hungary
2 Geographical Research Institute, Hungarian Academy of Sciences, Budapest, Hungary
*Corresponding author’s e-mail: szalaiz@iif.hu
Our presentation focuses on spatial differences of soil redox condition, on causes of
theses differences and on effects on seasonal dynamics of dissolved iron. Study areas
are located in a hilly headwater area (Szabadszántók, SW Transdanubia, Hungary) and
in a lowland area (Geje Plain, Danube-Tisza Interfluve, Hungary). Soil temperature,
wind speed (at 1m), incident solar radiation (PAR), soil pH, soil Eh and dissolved iron
were monitored. Measurements have been taken in four different patches in
Szabadszántók, and three different patches in Gerje Plain: sedge (Carex vulpina, Carex
riparia), horsetail (Equisetum arvense), common nettle (Urtica dioica), reed
(Phragmites communis). Measurements focused on differences between core parts of
patches and between edge and core areas. pH and Eh characteristics have been
measured individually in the studied patches. Soil Eh, pH and dissolved iron have
shown seasonal dynamics. Higher redox potentials and higher pH values were measured
between late autumn and early spring in both study areas. The increasing physiological
activity of higher plants causes (directly or indirectly) more acidic and more reductive
soil environment and it leads to higher spatial differences. Iron content of soil solution
also has shown strong correlation with soil redox conditions. Although temperature is
an essential determining factor for Eh and pH, our results suggest that it rather have
indirect effects through plants on wetlands. The spatial patterns of the studied
parameters are influenced by the water regime, micro-topography, and climatic
conditions and by direct and indirect effects of vegetation. The indirect effect can be the
shading, which has influence on soil temperature and on the incident solar radiation
(PAR).
Key words: wetland, redox, dissolved iron, Carex, Phragmites
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