TOLERANCE INDEX AS INDICATOR OF PLANT SENSITIVITY TO SOIL POLLUTION WITH HEAVY METALS IN AGRICULTURAL ECOSYSTEMS

摘要

Sensitivity of two pasture plant species (rye cultivated for green mass and spring barley) on increasing soil pollution with heavy metals, depending on differentiated soil reaction and the content of fraction below 0.02 mm in soil was investigated during 3-year micro-plot field experiments. Sensitivity of plants to heavy metals was evaluated based on the Tolerance index, which is a ratio of growth inhibition of tested plants, cultivated on contaminated soil when compared with control plants. Multicon-tamination of soil with four heavy metals (Zn, Pb, Cd and Cu) resulted in considerable yield reduction in investigated species, proportional to soil pollution with these elements. Plant tolerance for incidence of heavy metals in soil decreased with an increasing level of soil pollution with heavy metals as well as with soil acidification. Sensitivity of plants to exceeding amounts of heavy metals in soils was lower when grown on soils with greater content of fraction below 0.02 mm when compared with light soils with small capacity of sorption complex.