soil - Lublin

silts. The content of C org in the humus horizons varies from 1.4 to 2.72%, with the
lowest value in the middle part of the eroded hill slope. In that part of the slope, the
sub-humus horizon is characterized by a similar content of C org (2.04%), as opposed
to the sub-humus horizons in the upper (0.35%) and the lower (1.16%) parts
of the slope. The total specific surface area, characterizing jointly the granulometric
composition and the humus content, indicates a certain differentiation – higher
values (40.44 i 39.78 m 2 g -1 ) were observed in the soil on the slope, and lower values
in the soil on the upper and the lower parts of the slope (27.6-37.3 m 2 g -1 ). The
values of the external specific surface area tend to decrease in the soils from the
upper part of the slope (15.31 m 2 g -1 ), through the middle part (10.88 m 2 g -1 ) towards
the lower part of the slope (8.97 m 2 g -1 ). The reaction of the soils studied is neutral,
and even alkaline in the soils on the upper part of the slope.
Table 1.
Basic soil properties
granulometric composition
Corg. S H
(% of fraction in mm)
2 O S N 2
Location
pH H
0.1– 0.05– 0.02– 0.005– <
2 0
1–0.1
% m 2 g -1 m 2 g -1
0.05 0.02 0.005 0.002 0.002
A 6 9 53 21 3 8 2.28 36.78 15.31 8.11
1
B 2 10 50 23 6 9 0.35 37.30 14.92 8.14
2
3
A 4 13 50 20 5 8 1.94 40.44 10.88 7.06
B 4 10 50 21 6 9 2.04 39.78 12.55 7.01
A 8 14 58 13 2 5 2.72 35.36 8.97 7.60
B 3 13 54 19 4 7 1.16 27.60 9.44 7.91
4 A 6 17 58 6 8 5 2.28 34.02 6.40 7.88
The moisture relations of the soils on the hill slope under study [Orlik, 1979]
are affected by atmospheric precipitation, the average annual sum of which is 570
mm with a predominance in the summer season (Gliński and Dębicki, 2000b) when
daily precipitation of up to 30 mm are a frequent occurrence. This causes surface
runoff of the soil, the infiltration coefficient of which is much higher in the upper
(2.30 cm h -1 ) than in the lower part of the slope (1.66 cm h -1 ) [Gliński and Dębicki,
2000a].
In 2003, soil samples for laboratory analyses were taken from three places on
the slope studied (upper part -1, middle part -2 and lower part -3 and 4) from the
humus horizon (A 0-20 cm) and the sub-humus horizon (B 20-40 cm). The soil
samples were flooded with distilled water (at the ratio of 1:1) and incubated at 5,
10 and 20° C. In the course of the incubation, at different time intervals depending
on the incubation temperature, Eh was measured in the soil suspension by means of
PIONer meter made by Radiometer.
Values obtained from the measurements (n = 20) permitted the determination
of the dynamics of Eh in the course of the incubation process, and the determina-
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