Joint International Conference on Long-term Experiments ...

RESULTS
The effect of treatments on the studied soil characteristics is presented as a mean of the
three years (2003-2005).
Soil moisture content (Figure 1) varied between 12.69 and 14.38 % (mass %) in the
average of three years. In treatments with bentonite, a significant increase was observed
in moisture content, 2-3% higher than in treatments with bentonite composted with
manure.
Moisture content
(mass %)
15
13
11
9
7
5
1 2 3 4 5 6 7 8 9 10
Treatments
Figure 1: The effect of bentonite on soil moisture content
The pH value of soils (Figure 2) increased significantly in both treatment series and
solutions (H2O; KCl). Bentonite treatments increased the pH value more than the
bentonite + manure treatments.
pH
7
6
5
4
3
1 2 3 4 5 6 7 8 9 10
pH (H2O)
Treatments
pH (KCl) y1
18
13
8
3
Hydrolytic
acidity
(y1)
Figure 2: The effect of bentonite on the pH and hydrolytic acidity of soil
A considerable reduction was observed in the hydrolytic acidity (y1) (Figure 2) with
increasing pH. In both treatment series, even small dosages (5 t/ha; 5+9 t/ha) caused a
significant reduction, while the change was smaller in the case of higher dosages.
The NO3-N content of soil (Table 1) reduced, though not always significantly, as a
result of bentonite treatments. This cannot be stated about the bentonite + manure
treatments where NO3-N content increased in proportion to the increase in dosages. As a
249