Joint International Conference on Long-term Experiments ...

Ca and Mg content (mg/kg)
1400
1200
1000
800
600
400
200
0
2001 2004 2005 2001 2004 2005
Ca content Mg content
Control 200 kg/ha
Figure 2: The effect of K fertilization on the Ca and Mg content of winter wheat
samples
DISCUSSIONS
In the calcerous chernozem soils in Iregszemcse and Nagyhörcsök the applied N
increased the Mg and Mn content of the wheat grain samples in dry years and decreased
in humid years. We cannot draw the same conclusion from the results of the meadow
chernozem soil with salt in the deeper layers in Karcag. The increase of the Mnconcentration
is probably related to the decrease of soil pH in consequence of nitrogenapplying.
The application of N fertilizer increased the Ca content of the wheat grain
samples in all three research sites in every statistically proved case. The unique Caincreasing
effect might be the result of the considerable amount of Ca as additional
element in the fertilizer.
As regards phosphorus fertilization, we found that its effect on the nutrient content
depends on the production site and the soil type. In Nagyhörcsök and Iregszemcse, the
application of phosphorus increased the Mg and Mn content of the wheat grain samples
in every statistically proved cases, while in Karcag it had no effect on the concentration
of these elements.
The K content of the soil was sufficient in Karcag, while in Nagyhörcsök and
Iregszemcse it was medium, therefore we expected that the effect of K fertilization
would have higher effect at these cropping sites. Contrary, the nutrient-increasing effect
of K fertilization was proved only in Nagyhörcsök. At the Iregszemcse research site,
although the K supply was only medium, the K fertilization had no effect on the nutrient
content probably due to other soil-chemical factors.
The results of the analysis conducted in our accredited laboratory demonstrate that
the effect of the K and P fertilizers on the Mg and Mn concentration depends rather on
the production site, while the effect of the N fertilizer depends on the crop year.
260