The contents of the exchangeable, reducing and oxydising fractions of lead, cadmium, zinc and nickel were researched in the soil in partly controlled conditions. The solutions of 100 ppm of Cd, and 1000 ppm of each Zn and Ni were intorduced to the soil of approximately homogeneouseous physical and chemical characteristics, which was held in the containers. Compared to the control, the greatest differences in the exchangeable and reducing fractions were measured for cadmium. Zinc had an increase of the exchangeable fraction, and the decrease of the reducing and oxydising fractions. Nickel had the lowest changes of the contents of exchangeable, reducing and oxydising fractions. Compared to the control, the heights of the clone Populus x euramericana EA8 and the clone Populus deltoides PD5 were greater in the tested soil samples.