In this experiment the effects of lead and lead-free petrol applied at the following doses of: 0, 2, 4 and 6 cm(3) . kg(-1) of soil on growth and development of triticale and biochemical properties of the soil were studied. For detoxication of petrol organic amendment with barley straw was applied. The experiment was performed in two experimental series with and without triticale cover.
It was found that soil contamination by petrol adversely affected growth and development of tested crops. Barley straw appeared to be ineffective in detoxication of the contaminated soil. Lead and lead-free petrol (irrespective of plant cover and application of straw) adversely affected activity of soil dehydrogenases and urease. Straw application and growing of triticale positively affected biochemical properties of the soil. These positive effects were diminished by petrol, irrespective of the lead addition. Biochemical index of soil fertility calculated on the basis of enzymatic activity and carbon content was negatively correlated with the level of soil contamination by petrol and positively with triticale yield.