Joint International Conference on Long-term Experiments ...

ABSTRACT
THE EFFECT OF NITROGEN SUPPLY, LIMING AND NICKEL
CONTAMINATION ON THE PRODUCTIVITY OF RYEGRASS
(Lolium perenne L.) IN A GREENHOUSE EXPERIMENT
Marianna Sipos, Imre Vágó
University of Debrecen, Faculty of Agriculture
Department of Agricultural Chemistry and Soil Science
H-4015 Debrecen, P.O.Box 36.
It is well known that the dry matter production of plants is determined by the nutrient
and water supply and calcium carbonate content of soils and the amount of toxic
materials (besides their genetic potential). However, it is not known how the
anthropogenic pollutions (e. g. the heavy metal ion content of sewage) modify the effect
of these factors.
For studying this phenomenon, experiments were carried out on two extremely
different soils (leached calcareous chernozem with good fertility and acidic shifting
sand soil with low buffering capacity and humus content). In the pot experiment, the
effect of four factors (soil, nitrogen supply, nickel loading and CaCO3 treatment) on the
dry matter production of perennial ryegrass (Lolium perenne L.) was studied.
In the experiment, the dry matter yield of plants was measured in the different
treatments and treatment combinations.
On chernozem soil, nitrogen had the greatest effect on yield. In the sum of cuts,
lime had a yield-increasing effect, while nickel had no significant effect on yielding
capacity.
On shifting sand soil significant differences were found in the effect of treatments
on yield: nitrogen and lime, and nickel ion have exerted their positive and negative
effect, respectively; under high Ni-loading chlorotic symptoms could be observed
visually on plants. The yield-reducing effect of nickel was striking mainly in the
treatments without lime, while in limed variants the yield-depressing effect of Ni
contamination was more moderate.
Calcium carbonate had a stronger influencing effect on dry matter formation than
nitrogen treatments. These results indicate that improving the pH value of acidic soils is
important since in addition to improving yielding-capacity, it also limits the depressing
effect of toxic elements.
Keywords: Nitrogen, calcium carbonate, nickel contamination, productivity of ryegrass
INTRODUCTION
Nowadays, environmental considerations, study of environmental pollution and
mitigation of damages are becoming increasingly important. Anthropogenic pollution
represents a serious burden for the living and non-living environment. It might happen
that our striving to protect the environment and reduce the pollution will not be efficient
enough without satisfactory knowledge on the sources of danger. A good example of
this is the heavy metal pollution from sewage sludge applications, which can limit the
favourable yield-increasing effect of sewage or can even reduce yields.
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