Joint International Conference on Long-term Experiments ...

NPK
7:20:30
Table 2. Influences of fertilization (spring 2003) on soil characteristics
The experiment Korenicani: 0-30 cm of soil depth
(sampling 20 October 2005)
NH4Acetate-EDTA extraction (pH 4.65): concentrations in mg kg -1 of soil
kg ha -1 P2O5 K2O Ca Mg S Fe Mn Zn Cu Cd
a) 0
b) 1250
c) 2500
d) 3750
64.7
62.7
154.3
155.0
100.4
109.7
147.0
153.3
1835
1764
2100
2067
299
298
365
357
7.9
7.8
9.2
8.6
448
421
597
590
261
245
269
267
2.68
2.65
3.19
3.23
3.59
4.49
4.39
4.21
0.077
0.073
0.089
0.091
LSD5% 74.9 34.0 ns ns ns 78 ns ns ns ns
Mean 109.2 127.6 1942 330 8.4 2.94 261 514 4.17 0.082
General agrochemical soil test
pH AL-method: mg g -1 %
a) 0
b) 1250
c) 2500
d) 3750
H2O KCl P2O5 K2O Humus
6.45
6.46
6.87
6.82
5.12
5.12
5.64
5.53
84.7
96.3
164.7
172.0
85.0
99.3
149.7
176.7
1.94
1.92
1.99
1.94
LSD5% 0.23 0.36 28.6 24.0 n.s.
Mean 6.65 5.35 129.4 127.7 1.95
The applied fertilization had the most influences on maize nutritional status in the first
year of testing (2003) because significant differences for P, K, Mn (increasing trend)
Ca, Mg, Mn and Zn as well (decreasing trend) were found. In the second year (2004)
non-significant differences were found, while in the third year (2005) significant
differences were found for P, K and Mg only (Table 3). It is important that cadmium
status in maize plant was independent on applied fertilization because there are
examples in literature that application of the high P rates are mainly in conncetion with
increases of Cd concentrations in plant (Bergmann, 1992; Mengel and Kirkby, 2001).
Ameliorative fertilization had mainly low influences on maize grain composition
because only in the third year of testing significant differences for K, Mg (increases)
and Zn (decrease) status were found. Cd concentrations in maize grain were under
detectable range of the applied analytical procedure (Table 4).
Loncaric et al. (2005) applied 500 and 1000 kg ha -1 P2O5 and K2O alone and in
their combination on standard fertilization. Although low levels of P and K were found
by the soil test (AL-method), maize yields were similar for applied treatments in both
years. For this reason, in question is scientific application of AL-method in
interpretation of soil nutritional status for this and similar soil types. Probably acid
reaction of soil could be responsible for low influences of ameliorative fertilization on
maize yield in our study and in the study Loncaric et al. (2005).
Also, with aim of more precise prediction of soil nutritional status it is need
inclusion soil testing by application of different extraction methods.
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