The aim of this study was to test the hypothesis that a combined treatment of copper contaminated acid soil with lime and a coal powder decreases copper toxicity due to a synergetic effect of pH increase and association of Cu2+ ions in organo-mineral complexes. A two-year-long pot experiment with alfalfa was carried out on a pseudopodzolic soil contaminated with four Cu levels in the range 0-900 mg kg-1 soil. The amendments applied were lime, coal powder and a precomposted mixture of lime and coal powder. The compost and lime application increased yield and decreased copper content in plants at all levels of copper pollution. Coal powder alone depressed plant growth. The combined application of lime and coal powder maintained soil pH in the optimum range (5.1-5.6) during the whole experiment and had a pronounced effect on yield of the second and next crops, depending on the level of liming.