Direct and subsequent effect of compost and poultry manure on the bioavailability of cadmium and copper and their uptake by oat biomass

Direct and subsequent influence of added organic materials on changes of cadmium and copper bioavailability in soil and their accumulation in aboveground oat (Avena sativa L.) biomass was studied in a three-year experiment. Mineral NPK, poultry manure and two types of composts were used as fertilizers. The average portion of available cadmium and copper from their total content in soil in all treatments was 0.94% and 0.25%, respectively. After application of poultry manure the concentration of available Cd increased during experimental years, contrary to Cu. The Cd uptake increased proportionally with available Cd content in soil almost in all treatments during experi mental years (correlation coefficient R = 0.54; P < 0.05). The Cu uptake was however different than Cd uptake, ma inly in the second and third year. The lowest uptake of Cu was found in the first experimental year and was in close positive correlation with yields of dry biomass.