The three-year pot experiment was aimed to show the influence of such fertilizers as fresh and composted sewage sludge (from Siedlce and Łuków), manure, and their mixtures with calcium oxide and brown coal ash on copper and zinc contents in plants and soil. Copper and zinc concentrations were lower in plants fertilized with sewage sludge and manure mixed with CaO and ash than in plants treated with these substances with no additives. Content of heavy metals in maize and sunflower fertilized

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... sludge and manure mixtures with brown coal ash was higher as compared to their mixtures with calcium oxide. The composting of sewage sludge, manure, and their mixtures with CaO and ash reduced the copper content and increased the zinc content in both test plants. The content of these metals in the soil similarly increased after its fertilization with the same sewage sludge and its mixtures with calcium oxide and brown coal ash.