soil - Lublin

REDOX RELATIONS IN A LOESS SOIL ON ERODED HILL SLOPE
Gliński P., Stępniewska Z.
INTRODUCTION
Loess soils are among the group of silty formations with a chemical composition
differentiated with relation to the intensity of erosion processes [Boardmann
et.al., 1994; Gliński and Dębicki, 2000 a, b; Mazur et. al., 1972; Ziemnicki and
Łoś, 1979]. They contain clay minerals from the montmorillonite group, or mixed
montmorillonite-illite structures. Loess soils are characterized by a high level of
water retention (Haplic Luvisos and Eutric Combisols) [Michalczyk, 1998]. Typologically,
they are classified among the grey-brown podzolic (lessive) soils and the
brown soils [Turski et.al, 1993]. Topside gleying that is sometimes encountered in
lessive soils indicates periodic disturbances in the water-air relations in the soils.
Soil redox relations, expressed by means of the Eh index (mV), determine the
stage of processes of the reduction or oxidation of soil components [Carter,1980;
Gliński and Stępniewska 1986; Gliński et. al.,2000].
Under the conditions of insufficient oxygenation of soil, caused by eg. excessive
soil moisture content, reduction of oxidized forms takes place, successively, of
nitrates, manganese oxides, iron and sulfur, in the course of which the Eh index
may even assume negative values [Patrick, 1981; Patrick and Jugsujinda].
Soils developed from loess formations are among the most susceptible to the
lowering of Eh value under the conditions of insufficient oxygenation [Stępniewska,
1996], and therefore to rapid reduction of the oxidized forms of their
components. The process, in the case of eroded areas, may result, under specific
weather conditions, in the migration of such components downhill and on to the
water course. Water economy in basins in agricultural regions is one of the current
problems related to the phenomenon of recurring floods [Mioduszewski, 1997,
1998; Walczak et. al., 1998].
The objective of the study was to investigate predicted changes in the Eh of
soils on an eroded loess hill slope, under assumed moisture and temperature conditions.
The results presented herein constitute a fraction of a larger work concerned
with predicted changes in the redox processes and their effects, studied on the example
of a small basin under intensive agricultural use, characteristic for the loess
areas of the Lublin Upland region.
OBJECT AND METHOD OF THE STUDY
The object of the study was an eroded loess hill slope at the locality of Baszki
near Lublin, located in the Ciemięga river basin in the north-east part of the Nałęczów
Plateau, a sub-region of the Lublin Upland.
The hill slope, with an angle of slope of about 4°, is covered with grey-brown
podzolic and brown soils (Tab. 1) with the granulometric composition of loamy
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