Joint International Conference on Long-term Experiments ...

Relatív termés (100 NP/NPK), %
3.A. Alfalfa 3.B. Alfalfa
Y’ = 100 (1-10 –cx ); n = 23; Y’ = 1/(ax+b); n = 23
c: = 0.0109; r = 0.80 a = 0.03; b = 0.94; r = 0.74
100
4.0
80
60
40
20
0
0 100 200 300 400 500
AL-K2O, mg/kg
Terméstöbblet (NPK-NP), t/ha
3.0
2.0
1.0
0.0
0 100 200 300 400 500
AL-K2O, mg/kg
Figure 3. Relationship between the AL-K 2O contents of K control (NP) plots and responses of
alfalfa to K fertilization, calculated from the database of Hungarian field trials on K
fertilization, 1960–2000, using the Bray-Mitscherlich approach
The AL- (ammonium-lactate) (Egner, Riehm and Domingo 1960) soluble K indicated
the natural K- supplying power of the different soils adequately. With higher soil clay
contents in the trials, the original K supplying capacity of the soils was usually better.
Maize (and wheat) responses to K showed a better correlation with the soil clay
contents, than with the clay mineral compositions, resp.
Table 1. The effect of soil texture on responses to K application in Hungarian field trials with
maize, set up between 1960 and 2000
Soil
texture
groups
Number
of trials
(n)
homok h. vályog vályog a. vályog agyag
K A * AL-K 2 O
mg/kg
(NP)
K 2 O dose
kg/ha**
(K-control)
Grain yield
on NP plots
(NP/NPK)
Relative
yield,%
(NPK-NP)
Surplus,
t/ha
(NPK-NP)
Sands 13 29 80 120 4,27 71 1,91
S. loams 8 36 128 100 5,54 88 0,71
Loams 20 39 159 54 6,17 93 0,43
C. loams 27 45 187 33 6,26 97 0,19
Clay soils 5 55 206 0 7,81 100 0,00
Mean 73 40 155 59 5,90 90 0,61
*Upper limit of plasticity, according to Arany (similar to the US plasticity index).
** K 2 O doses needed for maximum economic yields (~ 95% of maximum yield)
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