C - Lublin

million cells/g soil
25
20
15
10
5
0
Burial place “Abganerovo”, light-chestnut soil
SA NA RM
PS-1 PS-2 PS-3 PS-4 MS
Burial place “Kolobovka”, light-chestnut soil
million cells/g soil
25
20
15
10
5
0
PS-5 PS-6 PS-7 MS
SA – soil agar (microorganisms consuming nutrient elements from poor environment)
NA – nitrite agar (microorganisms consuming humus substances)
RM – rich medium (microorganisms consuming an easily available organic matter)
Fig. 1. Quantity of microorganisms of various trophic clusters in the horizon B2 in
the paleosols (PS) and modern surface soils (MS)
reduction of the first and second parameters, whereas the index of oligothrophicity
grows up. This index expresses the ability of microbial community to use nutrient
elements from poor environment: the poorer nutrient conditions are the higher
index of oligothrophicity is.
The temporary and spatial variability of trophic structure of soil microbial
community in several regions of the steppe zone has been described. For instance,
during the last 3600 years in the saline chestnut soils in the river Esaulovsky Aksay
valley the microorganisms consuming nutrient elements from poor environment
prevailed (74-97%) (Table 1). These microorganisms also prevailed (69-77%) in
the light-chestnut soils developed on the saline loams in the Lower Volga region
under more arid climate. In the light-chestnut soils, developed under conditions of
less saline soil-forming rocks and higher precipitation on the watershed areas of
Ergeny Upland the microorganisms growing on the rich organic medium prevailed.
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