Corn was grown for green matter in a pot experiment, in which soil was fertilized with composts alone or in combination with 3 g N per pot (urea). The composts were made in wooden boxes, measuring 50×60×60 cm. They were composted for 3.5 months, until the temperature in the composts became stable and equal to the ambient temperature. Rates of the composts were balanced with amounts of added nitroge, such as 6.0 g N per pot. A one-factor experiment was conducted in Kick-Brauckmann pots, kept in a greenhouse at the University of Warmia and Mazury in Olsztyn. After harvest, fresh matter of stems and leaves as well as corn cobs was determined. Next, the plant samples were dried to determine the dry matter content and finally, after mineralisation, the concentration of Cu, Zn and Mn was determined by atomic absorption spectrophotometry. The composts significantly reduced the concentration of zinc and manganese in the vegetative yield of cor (lstems and leaves). Urea applied in combination with the composts very strongly increased the concentration of manganese and, to a lesser degree, the level of zinc and copper in vegetative organs. In corn cobs, the application of urea increased only the content of manganese. Urea had a stronger effect on increasing the weight of cobs rather than the vegetative mass of corn plants. The uptake of Cu, Zn and Mn was more evidently conditioned by the accumulation of these elements in dry matter than by the total weight of corn plants. The extent of the relationship between the uptake of Cu, Zn and Mn and their concentration of corn biomass is expressed the by corresponding correlation coefficients: 0.66, 0.65 and 0.68.