Changes in the availability of heavy metals and content of organic carbon in polluted soil after the application of an organic-mineral fertilizer obtained from brown coal

An organic-mineral fertilizer obtained from brown coal, the Rekulter when applied to polluted soil increased the content of the total organic carbon and pHKCl. The content of Cd and Zn soluble in 1M HCl were approximately 80% and for Ni and Pb were about 90% of the total content. The content of soluble Zn, Pb, Cd and Ni in 0.01 CaCl2 decreased when the application rate of the Rekulter was increased. The Rekulter reduced the content of cadmium soluble in 0.01 CaCl2 on average by 62% and nickel by 81% compared to pots not fertilized with this preparation. In the case of lead the decrease was about 2% and for zinc, about 35%.