Joint International Conference on Long-term Experiments ...

Western Canadian hard red spring wheat crops were characterized for cadmium, copper,
iron, manganese, selenium and zinc by Gawalko et al. (2002). Samples were received
from crop districts in Manitoba, Saskatchewan and Alberta for the 1996, 1997 and 1998
crops. Year-to-year variations in grain chemistry are small for Cd, Mn, Se and Zn, but
Cu and Fe contents show 12% and 9% decreases respectively over the three years. The
overall variability for the plant-essential trace elements, Cu, Fe, Mn and Zn, is low in
comparison with Cd and Se. It is demonstrated that the spatial variation in crop
chemistry across the Canadian Prairie wheat producing region is greater than the year to
year variations.
To compare the effects of organic manuring and inorganic fertilization, the
contents of trace elements in wheat harvested from a field experiment were analysed.
Inorganic fertilization compared to organic manuring increased the content of
manganese in wheat. Kirkham (1983) studied the effect of the sewage sludge on the
non-essential elements (Cd, Cr, Ni, Pb), as well as nine essential elements (N, P, K, Ca,
Mg, Cu, Fe, Mn, Zn) content of wheat samples in Manhattan, Kansas. Soil and winter
wheat were sampled in 1980 after a total of 128 t ha −1 of sludge (dry-weight basis) had
been added to the soil (32 t ha −1 year −1 ) since 1976. Soil in sludge-fertilized fields had
more N, P, K, Mg, Fe, Cu, Mn, Zn, Cd, Cr and Ni than did soil from the control fields.
In general, concentrations of essential elements in plants grown on sludge were similar
to concentrations of essential elements in plants grown with inorganic fertilizer.
Based on the results of long-term field trials, Kádár (1991) found that after
fertilization the following proved changes occurred in the concentrations of the
individual elements: N fertilization increased the Al and Mn content; P fertilization
increased the following: Al, B, Ca, P, Sr and decreased Zn content. K fertilization
increased the Ba and K content and decreased Mg content.
The nitrogen fertilizers decrease the soil pH (Debreczeni and Debreczeniné, 1994)
and it is affect the uptake of mineral elements with special regard to the Mn-uptake.
MATERIALS AND METHODS
The assay demonstrates the results of the researches in different soils in Hungary within
the framework of the National Long-term Field Trials. Field trials started in 5 fields in
1966 and in 4 fields in 1967. The fundamental conception was to use 4-year crop
rotation: winter wheat – corn – corn – peas, and winter wheat – corn – corn – winter
wheat, out of which peas were excluded in 2000. The researches are done in split-splitspot
arrangement, in four repetitions.
The analyzed winter wheat grain samples are from the corn – corn - winter wheat -
winter wheat crop rotation. Out of the different fertilization doses we used the results of
the nutrients in the control and high-dose plots in our calculations. The applied fertilizer
doses were the following: 0 – 150 – 200 kg/ha N, 0 – 100 – 120 kg/ha P, 0 – 100 – 200
kg/ha K, the other two active substances remained the same. When applying the
fertilizer, we have to consider that besides active substances additional elements are
given as well. The following includes the quantity of the additional elements in
Ammonium-nitrate, Superphosphate and Potassium-chloride fertilizers that are
important in our analysis (mg/kg; %):
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