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profiles were typical for catena positions, i.e. the plateau position was the non-eroded
region, the middle slope position was low eroded, the lower slope position was the most
eroded and at the valley the accumulated soil profile was found.
Four soil core samples were taken in each points along the transect from the upper 5 cm
by using 5 cm diameter sampling pots.
RESULTS AND DISCUSSIONS
The results of the laboratory analyses are given in Table 1. The depth of soil organic
matter was 90 cm in the non eroded profile, whereas it was only 10 cm at the highly
eroded site showing high physical degradation. The soil organic carbon (SOC) content
and the cation exchange capacity (CEC) of the soils decreased with increasing erosion
rate. The water soluble carbon (WSC) showed similar tendency. As for the bulk density
(BD), higher values were found in the upper slope positions. Concerning the enzymatic
characterization, less activity of urease (involved in N cycle) and
ß-glucosidase (involved in the C cycle) were experienced in the highly degraded slope
positions, suggesting less biological activity related to degradation.
Table 1: General laboratory parameters of the top horizons
of the four soil profiles along the catena
Profile DH SOC WSC WSCh CaCO3 CEC pH Ure B-Gl Texture BD
(upper h.) cm % ppm ppm % cmol·kg -1
μmols μmols FAO g·cm -3
NE 90 2,2 106,2 2,1 0 30 6,1 0,75 21,14 CL 1,4
LE 40 1,5 103,6 1,4 0 28 6,1 0,66 17,20 CL 1,5
HE 10 0,5 95,5 7,6 12 24 6,1 0,49 12,44 CL 1,3
AP 80 2,5 119,2 6,4 2 40 7,6 1,28 35,61 CL 1,2
Profile designations: NE – Non Eroded, LE – Low Eroded, HE – High Eroded,
AP – Accumulated Profile; DH - depth of humus layer (cm); SOC – Soil organic carbon
(%); WSC - Water soluble carbon (ppm); WSCh - Water soluble carbohydrates (ppm);
CEC - Cation exchange capacity (cmol·kg -1 ); Ure – Urease activity (μmols N-
NH4 + /g.h); B-Gl – B-Glucosidase activity (μmols PNF/g.h); CL- clay loam; BD - Bulk
density (g·cm -3 ).
The degradation of soil fauna was examined by the number and the species compostion
of collembolans along the erosion gradient. Eleven sampling points (Figure 1) were
chosen along the slope along the four soil profiles that were examined in detail. Except
for the highest point (number 0 in Figure 1) in the transect, which might have been a
sampling error, abundances of springtails decreased highly. Concerning the erosion
grades, the soil living springtails showed significant differences in their abundances
(F(2,41)= 9.2, p