CHANGES IN THE CONTENT OF SOME MACROELEMENTS IN MAIZE (ZEA MAYS L.) AFTER APPLICATION OF FUEL OIL AND DIFFERENT NEUTRALIZING SUBSTANCES TO SOIL

The aim of the present study was to determine the effect of incremental doses of heating oil (0-20 g kg of soil) and neutralizing substances - mineral and organic ones - on the content of some macronutrients in maize (Zea mays L.). The effect of heating oil and neutralizing substances on concentrations of the analyzed macronutrients in maize was varied. The content of phosphorus in maize was positively correlated to incremental doses of heating oil; the accumulation of sodium, calcium and magnesium in maize assumed a parabolic function, while changes in the content of potassium were irregular. All the substances applied to soil had a limiting effect on the content of phosphorus but stimulated (except nitrogen) the accumulation of potassium in maize grown on soil contaminated with heating oil. Out of the tested soil-amending substances, bentonite was the most stimulating one with respect to sodium and the most limiting to calcium in maize. Zeolite and calcium oxide showed a stimulating effect and increased the content of calcium and magnesium in maize. Compost had a similar effect on the content of calcium, whereas nitrogen stimulated the accumulation of magnesium in maize.