Joint International Conference on Long-term Experiments ...

ABSTRACT
BIOLOGICAL INVESTIGATION ON AN EROSION CATENA
B. Szeder 1 , B. Simon 1 , M. Dombos 2 , T. Szegi 1
1 Szent István University, Department of Soil Science and Agrochemistry,
2103 Gödöllő, Páter K. u. 1. Hungary
2 Research Institute of Soil Science and Agrochemistry,
Budapest, Herman O. U. 15. Hungary,
Biological investigations were carried out on an erosion catena on Szent István
University Experimental Farm, north central Hungary. Four soil profiles (Chernozems
and Calcisols) were examined in detail for the general physical, chemical parameters.
The aim was to find out quantitative relationship between the physical and the
biological (and biochemical) degradation processes. The level of physical degradation
was expressed by the moisture retention capacity and the depth of humus rich horizon.
The degradation of soil fauna was examined by the number and the species composition
of collembolans along the transect in eleven sampling points. The physical degradation,
biochemical and biological parameters showed strong relationship: with increasing
erosion and decreasing depth of the humus layers most investigated parameters showed
degradation. The number and the abundance of Collembola had significant decreasing
tendency with increasing level of degradation. The results suggest that soil degradation,
decreasing moisture holding conditions affect strongly the collembolan community. The
physical, chemical parameters seemed to be more resistant to changes in soils compared
to the biological aspects, thus, it is assumed that the biological parameters can be used
as early indicators.
Keywords: degradation, biological indicators, Collembola, erosion catena
INTRODUCTION
Loss of soil organic matter is a global problem related to soils and the environment.
Most of the fertile Chernozems of agricultural soils in Hungary developed on calcareous
loess. Chernozems have been cultivated for several centuries in Hungary (Stefanovits,
1999). However, most of the Chernozem soils in the country has experienced some kind
of soil degradation, including decrease in organic matter, compaction, erosion and/or
structural degradation, mainly due to inappropriate land use practices. These
degradation processes are generally accompained by biological degradation, i.e. loss of
species richness. Soil fauna is essential in the decomposition processes of biomass,
synthesis of humus, mixing soil particles, development of soil structure and it influences
several other soil characteristics that determine normal soil functions. Soil degradation
processes influence the composition, population size and activity of the soil fauna
(Larsen, 2004; Bíró, 2005; Veisz, 2004).
Soil quality can be evaluated by using several soil parameters, depending on the
scale and objective of the evaluation. These parameters can be, for instance, the soil
organic matter and soil aggregate stability (Gardi et al., 2002). In case of an erosion
risk, soil quality can be characterized by using different parameters, such as organic
matter content, aggregate stability, and enzyme activities. However, these parameters
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